GooglyPlusPlus: Win Probability using Deep Learning and player embeddings

In my last post ‘GooglyPlusPlus now with Win Probability Analysis for all T20 matches‘ I had discussed the performance of my ML models, created with and without player embeddings, in computing the Win Probability of T20 matches. With batsman & bowler embeddings I got much better performance than without the embeddings

  • glmnet – Accuracy – 0.73
  • Random Forest (RF) – Accuracy – 0.92

While the Random Forest gave excellent accuracy, it was bulky and also took an unusually long time to predict the Win Probability of a single T20 match. The above 2 ML models were built using R’s Tidymodels. glmnet was fast, but I wanted to see if I could create a ML model that was better, lighter and faster. I had initially tried to use Tensorflow, Keras in Python but then abandoned it, since I did not know how to port the Deep Learning model to R and use in my app GooglyPlusPlus.

But later, since I was stuck with a bulky Random Forest model, I decided to again explore options for saving the Keras Deep Learning model and loading it in R. I found out that saving the model as .h5, we can load it in R and use it for predictions. Hence, I rebuilt a Deep Learning model using Keras, Python with player embeddings and I got excellent performance. The DL model was light and had an accuracy 0.8639 with an ROC_AUC of 0.964 which was great!

GooglyPlusPlus uses data from Cricsheet and is based on my R package yorkr

You can try out this latest version of GooglyPlusPlus at gpp2023-1

Here are the steps

A. Build a Keras Deep Learning model

a. Import necessary packages

import pandas as pd
import numpy as np
from zipfile import ZipFile
import tensorflow as tf
from tensorflow import keras
from tensorflow.keras import layers
from tensorflow.keras import regularizers
from pathlib import Path
import matplotlib.pyplot as plt

b, Upload the data of all 9 T20 leagues (BBL, CPL, IPL, T20 (men) , T20(women), NTB, CPL, SSM, WBB)

# Read all T20 leagues 
df1=pd.read_csv('t20.csv')
print("Shape of dataframe=",df1.shape)

# Create training and test data set
train_dataset = df1.sample(frac=0.8,random_state=0)
test_dataset = df1.drop(train_dataset.index)
train_dataset1 = train_dataset[['batsmanIdx','bowlerIdx','ballNum','ballsRemaining','runs','runRate','numWickets','runsMomentum','perfIndex']]
test_dataset1 = test_dataset[['batsmanIdx','bowlerIdx','ballNum','ballsRemaining','runs','runRate','numWickets','runsMomentum','perfIndex']]
train_dataset1

# Set the target data
train_labels = train_dataset.pop('isWinner')
test_labels = test_dataset.pop('isWinner')
train_dataset1

a=train_dataset1.describe()
stats=a.transpose
a

c. Create a Deep Learning ML model using batsman & bowler embeddings

import pandas as pd
import numpy as np
from keras.layers import Input, Embedding, Flatten, Dense
from keras.models import Model
from keras.layers import Input, Embedding, Flatten, Dense, Reshape, Concatenate, Dropout
from keras.models import Model

# Set seed
tf.random.set_seed(432)

# create input layers for each of the predictors
batsmanIdx_input = Input(shape=(1,), name='batsmanIdx')
bowlerIdx_input = Input(shape=(1,), name='bowlerIdx')
ballNum_input = Input(shape=(1,), name='ballNum')
ballsRemaining_input = Input(shape=(1,), name='ballsRemaining')
runs_input = Input(shape=(1,), name='runs')
runRate_input = Input(shape=(1,), name='runRate')
numWickets_input = Input(shape=(1,), name='numWickets')
runsMomentum_input = Input(shape=(1,), name='runsMomentum')
perfIndex_input = Input(shape=(1,), name='perfIndex')

# Set the embedding size as the 4th root of unique batsmen, bowlers
no_of_unique_batman=len(df1["batsmanIdx"].unique()) 
no_of_unique_bowler=len(df1["bowlerIdx"].unique()) 
embedding_size_bat = no_of_unique_batman ** (1/4)
embedding_size_bwl = no_of_unique_bowler ** (1/4)


# create embedding layer for the categorical predictor
batsmanIdx_embedding = Embedding(input_dim=no_of_unique_batman+1, output_dim=16,input_length=1)(batsmanIdx_input)
batsmanIdx_flatten = Flatten()(batsmanIdx_embedding)
bowlerIdx_embedding = Embedding(input_dim=no_of_unique_bowler+1, output_dim=16,input_length=1)(bowlerIdx_input)
bowlerIdx_flatten = Flatten()(bowlerIdx_embedding)

# concatenate all the predictors
x = keras.layers.concatenate([batsmanIdx_flatten,bowlerIdx_flatten, ballNum_input, ballsRemaining_input, runs_input, runRate_input, numWickets_input, runsMomentum_input, perfIndex_input])

# add hidden layers
# Use dropouts for regularisation
x = Dense(64, activation='relu')(x)
x = Dropout(0.1)(x)
x = Dense(32, activation='relu')(x)
x = Dropout(0.1)(x)
x = Dense(16, activation='relu')(x)
x = Dropout(0.1)(x)
x = Dense(8, activation='relu')(x)
x = Dropout(0.1)(x)

# add output layer
output = Dense(1, activation='sigmoid', name='output')(x)
print(output.shape)

# create a DL model
model = Model(inputs=[batsmanIdx_input,bowlerIdx_input, ballNum_input, ballsRemaining_input, runs_input, runRate_input, numWickets_input, runsMomentum_input, perfIndex_input], outputs=output)
model.summary()

# compile model
optimizer=keras.optimizers.Adam(learning_rate=.01, beta_1=0.9, beta_2=0.999, epsilon=1e-07, decay=0.0, amsgrad=True)

model.compile(optimizer=optimizer, loss='binary_crossentropy', metrics=['accuracy'])

# train the model
history=model.fit([train_dataset1['batsmanIdx'],train_dataset1['bowlerIdx'],train_dataset1['ballNum'],train_dataset1['ballsRemaining'],train_dataset1['runs'],
           train_dataset1['runRate'],train_dataset1['numWickets'],train_dataset1['runsMomentum'],train_dataset1['perfIndex']], train_labels, epochs=40, batch_size=1024,
          validation_data = ([test_dataset1['batsmanIdx'],test_dataset1['bowlerIdx'],test_dataset1['ballNum'],test_dataset1['ballsRemaining'],test_dataset1['runs'],
           test_dataset1['runRate'],test_dataset1['numWickets'],test_dataset1['runsMomentum'],test_dataset1['perfIndex']],test_labels), verbose=1)

plt.plot(history.history["loss"])
plt.plot(history.history["val_loss"])
plt.title("model loss")
plt.ylabel("loss")
plt.xlabel("epoch")
plt.legend(["train", "test"], loc="upper left")
plt.show()

Model: "model_5"
__________________________________________________________________________________________________
 Layer (type)                   Output Shape         Param #     Connected to                     
==================================================================================================
 batsmanIdx (InputLayer)        [(None, 1)]          0           []                               
                                                                                                  
 bowlerIdx (InputLayer)         [(None, 1)]          0           []                               
                                                                                                  
 embedding_10 (Embedding)       (None, 1, 16)        75888       ['batsmanIdx[0][0]']             
                                                                                                  
 embedding_11 (Embedding)       (None, 1, 16)        55808       ['bowlerIdx[0][0]']              
                                                                                                  
 flatten_10 (Flatten)           (None, 16)           0           ['embedding_10[0][0]']           
                                                                                                  
 flatten_11 (Flatten)           (None, 16)           0           ['embedding_11[0][0]']           
                                                                                                  
 ballNum (InputLayer)           [(None, 1)]          0           []                               
                                                                                                  
 ballsRemaining (InputLayer)    [(None, 1)]          0           []                               
                                                                                                  
 runs (InputLayer)              [(None, 1)]          0           []                               
                                                                                                  
 runRate (InputLayer)           [(None, 1)]          0           []                               
                                                                                                  
 numWickets (InputLayer)        [(None, 1)]          0           []                               
                                                                                                  
 runsMomentum (InputLayer)      [(None, 1)]          0           []                               
                                                                                                  
 perfIndex (InputLayer)         [(None, 1)]          0           []                               
                                                                                                  
 concatenate_5 (Concatenate)    (None, 39)           0           ['flatten_10[0][0]',             
                                                                  'flatten_11[0][0]',             
                                                                  'ballNum[0][0]',                
                                                                  'ballsRemaining[0][0]',         
                                                                  'runs[0][0]',                   
                                                                  'runRate[0][0]',                
                                                                  'numWickets[0][0]',             
                                                                  'runsMomentum[0][0]',           
                                                                  'perfIndex[0][0]']              
                                                                                                  
 dense_19 (Dense)               (None, 64)           2560        ['concatenate_5[0][0]']          
                                                                                                  
 dropout_19 (Dropout)           (None, 64)           0           ['dense_19[0][0]']               
                                                                                                  
 dense_20 (Dense)               (None, 32)           2080        ['dropout_19[0][0]']             
                                                                                                  
 dropout_20 (Dropout)           (None, 32)           0           ['dense_20[0][0]']               
                                                                                                  
 dense_21 (Dense)               (None, 16)           528         ['dropout_20[0][0]']             
                                                                                                  
 dropout_21 (Dropout)           (None, 16)           0           ['dense_21[0][0]']               
                                                                                                  
 dense_22 (Dense)               (None, 8)            136         ['dropout_21[0][0]']             
                                                                                                  
 dropout_22 (Dropout)           (None, 8)            0           ['dense_22[0][0]']               
                                                                                                  
 output (Dense)                 (None, 1)            9           ['dropout_22[0][0]']             
                                                                                                  
==================================================================================================
Total params: 137,009
Trainable params: 137,009
Non-trainable params: 0
__________________________________________________________________________________________________
Epoch 1/40
937/937 [==============================] - 11s 10ms/step - loss: 0.5683 - accuracy: 0.6968 - val_loss: 0.4480 - val_accuracy: 0.7708
Epoch 2/40
937/937 [==============================] - 9s 10ms/step - loss: 0.4477 - accuracy: 0.7721 - val_loss: 0.4305 - val_accuracy: 0.7833
Epoch 3/40
937/937 [==============================] - 9s 10ms/step - loss: 0.4229 - accuracy: 0.7832 - val_loss: 0.3984 - val_accuracy: 0.7936
...
...
937/937 [==============================] - 10s 10ms/step - loss: 0.2909 - accuracy: 0.8627 - val_loss: 0.2943 - val_accuracy: 0.8613
Epoch 38/40
937/937 [==============================] - 10s 10ms/step - loss: 0.2892 - accuracy: 0.8633 - val_loss: 0.2933 - val_accuracy: 0.8621
Epoch 39/40
937/937 [==============================] - 10s 10ms/step - loss: 0.2889 - accuracy: 0.8638 - val_loss: 0.2941 - val_accuracy: 0.8620
Epoch 40/40
937/937 [==============================] - 10s 11ms/step - loss: 0.2886 - accuracy: 0.8639 - val_loss: 0.2929 - val_accuracy: 0.8621

d. Compute and plot the ROC-AUC for the above model

from sklearn.metrics import roc_curve

# Select a random sample set
tf.random.set_seed(59)
train = df1.sample(frac=0.9,random_state=0)
test = df1.drop(train_dataset.index)
test_dataset1 = test[['batsmanIdx','bowlerIdx','ballNum','ballsRemaining','runs','runRate','numWickets','runsMomentum','perfIndex']]
test_labels = test.pop('isWinner')

# Compute the predicted values
y_pred_keras = model.predict([test_dataset1['batsmanIdx'],test_dataset1['bowlerIdx'],test_dataset1['ballNum'],test_dataset1['ballsRemaining'],test_dataset1['runs'],
           test_dataset1['runRate'],test_dataset1['numWickets'],test_dataset1['runsMomentum'],test_dataset1['perfIndex']]).ravel()

# Compute TPR & FPR
fpr_keras, tpr_keras, thresholds_keras = roc_curve(test_labels, y_pred_keras)

fpr_keras, tpr_keras, thresholds_keras = roc_curve(test_labels, y_pred_keras)
from sklearn.metrics import auc

# Plot the Area Under the Curve (AUC)
auc_keras = auc(fpr_keras, tpr_keras)
plt.figure(1)
plt.plot([0, 1], [0, 1], 'k--')
plt.plot(fpr_keras, tpr_keras, label='Keras (area = {:.3f})'.format(auc_keras))
plt.xlabel('False positive rate')
plt.ylabel('True positive rate')
plt.title('ROC curve')
plt.legend(loc='best')
plt.show()

The ROC_AUC for the Deep Learning Model is 0.946 as seen below

e. Save the Keras model for use in Python

from keras.models import Model
model.save("wpDL.h5")

f. Load the model in R using rhdf5 package for use in GooglyPlusPlus

library(rhdf5)
dl_model <- load_model_hdf5('wpDL.h5')

This was a huge success for me to be able to create the Deep Learning model in Python and use it in my Shiny app GooglyPlusPlus. The Deep Learning Keras model is light-weight and extremely fast.

The Deep Learning model has now been integrated into GooglyPlusPlus. Now you can check the Win Probability using both a) glmnet (Logistic Regression with lasso regularisation) b) Keras Deep Learning model with dropouts as regularisation

In addition I have created 2 features based on Win Probability (WP)

i) Win Probability (Side-by-side – Plot(interactive) : With this functionality the 1st and 2nd innings will be side-by-side. When the 1st innings is played by team 1, the Win Probability of team 2 = 100 – WP (team1). Similarly, when the 2nd innings is being played by team 2, the Win Probability of team1 = 100 – WP (team 2)

ii) Win Probability (Overlapping) – Plot (static): With this functionality the Win Probabilities of both team1(1st innings) & team 2 (2nd innings) are displayed overlapping, so that we can see how the probabilities vary ball-by-ball.

Note: Since the same UI is used for all match functions I had to re-use the Plot(interactive) and Plot(static) radio buttons for Win Probability (Side-by-side) and Win Probability(Overlapping) respectively

Here are screenshots using both ML models with both functionality for some random matches

B) ICC T20 Men World Cup – Netherland-South Africa- 2022-11-06

i) Match Worm wicket chart

ii) Win Probability with LR (Side-by-Side- Plot(interactive))

iii) Win Probability LR (Overlapping- Plot(static))

iv) Win Probability Deep Learning (Side-by-side – Plot(interactive)

In the 213th ball of the innings South Africa was slightly ahead of Netherlands. After that they crashed and burned!

v) Win Probability Deep Learning (Overlapping – Plot (static)

It can be seen that in the 94th ball of both innings South Africa was ahead of Netherlands before the eventual slump.

C) Intl. T20 (Women) India – New Zealand – 2020 – 02 – 27

Here is an interesting match between India and New Zealand T20 Women’s teams. NZ successfully chased the India’s total in a wildly swinging fortunes. See the charts below

i) Match Worm Wicket chart

ii) Win Probability with LR (Side-by-side – Plot (interactive)

iii) Win Probability with LR (Overlapping – Plot (static)

iv) Win Probability with DL model (Side-by-side – Plot (interactive))

v) Win Probability with DL model (Overlapping – Plot (static))

The above functionality in plotting the Win Probability using LR or DL with both options (Side-by-side or Overlapping) is available for all 9 T20 leagues currently supported by GooglyPlusPlus.

Go ahead and give gpp2023-1 a try!!!

Do also check out my other posts’

  1. Deep Learning from first principles in Python, R and Octave – Part 7
  2. Big Data 6: The T20 Dance of Apache NiFi and yorkpy
  3. Latency, throughput implications for the Cloud
  4. Design Principles of Scalable, Distributed Systems
  5. Cricpy adds team analytics to its arsenal!!
  6. Analyzing performances of cricketers using cricketr template
  7. Modeling a Car in Android
  8. Using Linear Programming (LP) for optimizing bowling change or batting lineup in T20 cricket
  9. Introducing QCSimulator: A 5-qubit quantum computing simulator in R
  10. Experiments with deblurring using OpenCV
  11. Using embeddings, collaborative filtering with Deep Learning to analyse T20 players

To see all posts click Index of posts

Computing Win-Probability of T20 matches

I am late to the ‘Win probability’ computation for T20 matches, but managed to jump on to this bus with this post. Win Probability analysis and computation have been around for some time and are used in baseball, NFL, soccer hockey and others. On T20 cricket, the following posts from White Ball Analytics & Sports Data Science were good pointers to the general approach. The data for the Win Probability computation is taken from Cricsheet.

My initial Machine Learning models could not do better than 62% accuracy. I created a data set of ~830 IPL matches which roughly came to about 280,000 rows of ball-by-ball match data but I could not move beyond 62%. Addition of T20 men moved the needle to 64% accuracy. I spent time tuning Deep Learning networks using Tensorflow and Keras. Finally, I added T20 data from 9 T20 leagues – IPL, T20 men, T20 women, BBL, CPL, NTB, PSL, WBB, SSM. I had one large data set of 1.2 million rows of ball by ball data. The data frame looks like

I created a data frame for each match from ball Num 1 to ballNum ~240 for the 1st and 2nd innings of the match. My initial set of features were ballNum, runs, runRate, numWickets. The target variable isWinner= {0,1} depending on whether the team has won or lost the match.

The features

  • ballNum – ball number for 1 ~ 240+ in data frame. 1 – 120+ for 1st innings and 120+ – 240+ in 2nd innings including noballs, wides etc.
  • runs = cumulative runs scored at the ball count
  • runRate = cumulative runs scored/ ballNum (for 1st innings) and runs= required runs/ball Num for 2nd innings
  • numWickets = wickets lost

The target variable isWinner can take values {0,1} depending whether the team won or lost

With this initial dataframe, even though I had close to 1.2 million rows of ball by ball data of T20 matches my best performance with vanilla Logistic regression & SVM in Python was about 64% accuracy.

# Read all the data from 9 T20 leagues
# BBL,CPL, IPL, NTB, PSL, SSM, T20 Men, T20 Women, WBB
df1=pd.read_csv('matchesT20M.csv')
df2=pd.read_csv('matchesIPL.csv')
df3=pd.read_csv('matchesBBL.csv')
df4=pd.read_csv('matchesCPL.csv')
df5=pd.read_csv('matchesNTB.csv')
df6=pd.read_csv('matchesPSL.csv')
df7=pd.read_csv('matchesSSM.csv')
df8=pd.read_csv('matchesT20W.csv')
df9=pd.read_csv('matchesWBB.csv')

# Create one large dataframe
df10=pd.concat([df1,df2,df3,df4,df5,df6,df7,df8,df9])
print("Shape of dataframe=",df10.shape)
print("#####################################")
stats=check_values(df10)
print("#####################################")
model_fit(df10)
#norm_model_fit(df,stats)
svm_model_fit(df10)

Shape of dataframe= (1206901, 6)
#####################################
Null values: False
It contains 0 infinite values

Accuracy of Logistic regression classifier on training set: 0.63
Accuracy of Logistic regression classifier on test set: 0.64
Accuracy: 0.64
Precision: 0.62
Recall: 0.65
F1: 0.64


Accuracy of Linear SVC classifier on training set: 0.52
Accuracy of Linear SVC classifier on test set: 0.52

With Tensorflow/Keras the performance was about 67%. I tried several things

  • Normalisation
  • Tried different learning rates
  • Different optimisers – SGD, RMSProp, Adam
  • Changed depth and width of Neural Network

However I did not get much improvement. Finally I decided to do some Feature engineering. I added 2 new features

a) Runs Momentum : This feature is based on the fact that more the wickets in hand, the more freely the batsmen can make risky strokes, hence increasing the momentum of the runs, This is calculated as

runsMomentum = (11 – numWickets)/balls remaining

b) Performance Index: This feature is the product of the run rate x wickets in hand. In other words, if the strike rate is good and fewer wickets lost at the point in the match, then the performance index is higher at that point in the match will be higher

The final set of features chosen were as below

I had also included the balls Remaining in the innings. Now with this set of features I decided to execute Tensorflow/Keras and do a GridSearch with different learning rates, optimisers. After a couple of hours of computation I got an accuracy of 0.73. I needed to be able to read the ML model in R which required installation of Tensorflow, reticulate and Keras in RStudio and I had several issues. Since I hit a roadblock I moved to regular R models

I performed WIn Probability computation in the following ways

A) Win Probability with Vanilla Logistic Regression (R)

With vanilla Logistic Regression in R using the ‘glm’ package I got an accuracy of 0.67, sensitivity of 0.68 and specificity of 0.65 as shown below

library(dplyr)
library(caret)
library(e1071)
library(ggplot2)

# Read all the data from 9 T20 leagues
# BBL,CPL, IPL, NTB, PSL, SSM, T20 Men, T20 Women, WBB
df1=read.csv("output2/matchesBBL2.csv")
df2=read.csv("output2/matchesCPL2.csv")
df3=read.csv("output2/matchesIPL2.csv")
df4=read.csv("output2/matchesNTB2.csv")
df5=read.csv("output2/matchesPSL2.csv")
df6=read.csv("output2/matchesSSM2.csv")
df7=read.csv("output2/matchesT20M2.csv")
df8=read.csv("output2/matchesT20W2.csv")
df9=read.csv("output2/matchesWBB2.csv")

# Create one large dataframe
df=rbind(df1,df2,df3,df4,df5,df6,df7,df8,df9)

# Helper function to split into training/test
trainTestSplit <- function(df,trainPercent,seed1){
  ## Sample size percent
  samp_size <- floor(trainPercent/100 * nrow(df))
  ## set the seed 
  set.seed(seed1)
  idx <- sample(seq_len(nrow(df)), size = samp_size)
  idx
  
}

train_idx <- trainTestSplit(df,trainPercent=80,seed=5)
train <- df[train_idx, ]

test <- df[-train_idx, ]
# Fit a generalized linear logistic model, 
fit=glm(isWinner~.,family=binomial,data=train,control = list(maxit = 50))

a=predict(fit,newdata=train,type="response")
# Set response >0.5 as 1 and <=0.5 as 0
b=as.factor(ifelse(a>0.5,1,0))
# Compute the confusion matrix for training data

confusionMatrix(
  factor(b, levels = 0:1),
  factor(train$isWinner, levels = 0:1)
)

Confusion Matrix and Statistics

          Reference
Prediction    
  0      1
         0 339938 160336
         1 154236 310217
                                         
               Accuracy : 0.6739         
                 95% CI : (0.673, 0.6749)
    No Information Rate : 0.5122         
    P-Value [Acc > NIR] : < 2.2e-16      
                                         
                  Kappa : 0.3473         
                                         
 Mcnemar's Test P-Value : < 2.2e-16      
                                         
            Sensitivity : 0.6879         
            Specificity : 0.6593         
         Pos Pred Value : 0.6795         
         Neg Pred Value : 0.6679         
             Prevalence : 0.5122         
         Detection Rate : 0.3524         
   Detection Prevalence : 0.5186         
      Balanced Accuracy : 0.6736         
                                         
       'Positive' Class : 0      

# This can be saved and loaded as    
saveRDS(fit, "glm.rds")
ml_model <- readRDS("glm.rds")    

Using the above ML model on Deccan Chargers vs Chennai Super on 27-04-2009 the Win Probability as the match progresses is as below

The Worm wicket graph of this match shows it was a closely fought match

B) Win Probability using Random Forests with Tidy Models – R

Initially I tried Tidy models with tuning for glmnet. The best I got was 0.67. However, I got an excellent performance using TidyModels with Random Forests. I am using Tidy Models for the first time and I have been blown away with how logically it is constructed, much like dplyr & ggplot2.

library(dplyr)
library(caret)
library(e1071)
library(ggplot2)
library(tidymodels)  

# Helper packages
library(readr)       # for importing data
library(vip) 
library(ranger)
# Read all the data from 9 T20 leagues
# BBL,CPL, IPL, NTB, PSL, SSM, T20 Men, T20 Women, WBB

df1=read.csv("output2/matchesBBL2.csv")
df2=read.csv("output2/matchesCPL2.csv")
df3=read.csv("output2/matchesIPL2.csv")
df4=read.csv("output2/matchesNTB2.csv")
df5=read.csv("output2/matchesPSL2.csv")
df6=read.csv("output2/matchesSSM2.csv")
df7=read.csv("output2/matchesT20M2.csv")
df8=read.csv("output2/matchesT20W2.csv")
df9=read.csv("output2/matchesWBB2.csv")

# Create one large dataframe
df=rbind(df1,df2,df3,df4,df5,df6,df7,df8,df9)

dim(df)
[1] 
1205909       8

# Take a peek at the dataset
glimpse(df)
$ ballNum        <int> 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28…
$ ballsRemaining <int> 125, 124, 123, 122, 121, 120, 119, 118, 117, 116, 115, 114, 113, 112, 111, 110, 109, 108, 107, 106, 1…
$ runs           <int> 1, 1, 2, 3, 3, 3, 4, 4, 5, 5, 6, 7, 13, 14, 16, 18, 18, 18, 24, 24, 24, 26, 26, 32, 32, 33, 34, 34, 3…
$ runRate        <dbl> 1.0000000, 0.5000000, 0.6666667, 0.7500000, 0.6000000, 0.5000000, 0.5714286, 0.5000000, 0.5555556, 0.…
$ numWickets     <int> 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3,…
$ runsMomentum   <dbl> 0.08800000, 0.08870968, 0.08943089, 0.09016393, 0.09090909, 0.09166667, 0.09243697, 0.09322034, 0.094…
$ perfIndex      <dbl> 11.000000, 5.500000, 7.333333, 8.250000, 6.600000, 5.500000, 6.285714, 5.500000, 6.111111, 5.000000, …
$ isWinner       <int> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,…

df %>% 
  count(isWinner) %>% 
  mutate(prop = n/sum(n))

set.seed(123)
df$isWinner = as.factor(df$isWinner)

# Split the data into training and test set in 80%:20%
splits      <- initial_split(df,prop = 0.80)
df_other <- training(splits)
df_test  <- testing(splits)

# Create a validation set from training set in 80%:20%
set.seed(234)
val_set <- validation_split(df_other, 
                            prop = 0.80)
val_set

# Setup for Random forest using Ranger for classification
# Set up cores for parallel execution
cores <- parallel::detectCores()
cores

#Set up Random Forest engine
rf_mod <- 
  rand_forest(mtry = tune(), min_n = tune(), trees = 1000) %>% 
  set_engine("ranger", num.threads = cores) %>% 
  set_mode("classification")

rf_mod
# The Random Forest engine includes mtry which is number of predictor 
# variables required at each decision  tree with min_n the minimum number # of 
Random Forest Model Specification (classification)

Main Arguments:
  mtry = tune()
  trees = 1000
  min_n = tune()

Engine-Specific Arguments:
  num.threads = cores

Computational engine: ranger


# Setup the predictors and target variable
# Normalise all predictors. Random Forest don't need normalization but
# I have done it anyway
rf_recipe <-
  recipe(isWinner ~ ., data = df_other) %>% 
  step_normalize(all_predictors())

# Create workflow adding the ML model and recipe
rf_workflow <- 
  workflow() %>% 
  add_model(rf_mod) %>% 
  add_recipe(rf_recipe)

# The tune is done for 5 different values of the tuning parameters.
# Metrics include accuracy and roc_auc
rf_res <- 
  rf_workflow %>% 
  tune_grid(val_set,
            grid = 5,
            control = control_grid(save_pred = TRUE),
            metrics = metric_set(accuracy,roc_auc))

$ Pick the best of ROC/AUC
rf_res %>% 
  show_best(metric = "roc_auc")

We can see that when mtry (number of predictors) is 5 or 7 the ROC_AUC is 0.834 which is quite good

# A tibble: 5 × 8
   mtry min_n .metric .estimator  mean     n std_err .config             
  <int> <int> <chr>   <chr>      <dbl> <int>   <dbl> <chr>               
1     5    26 roc_auc binary     0.834     1      NA Preprocessor1_Model5
2     7    36 roc_auc binary     0.834     1      NA Preprocessor1_Model3
3     2    17 roc_auc binary     0.833     1      NA Preprocessor1_Model4
4     1    20 roc_auc binary     0.832     1      NA Preprocessor1_Model2
5     5     6 roc_auc binary     0.825     1      NA Preprocessor1_Model1


# Select the model with highest accuracy
rf_res %>% 
  show_best(metric = "accuracy")
   mtry min_n .metric  .estimator  mean     n std_err .config             
  <int> <int> <chr>    <chr>      <dbl> <int>   <dbl> <chr>               
1     7    36 accuracy binary     0.737     1      NA Preprocessor1_Model3
2     5    26 accuracy binary     0.736     1      NA Preprocessor1_Model5
3     1    20 accuracy binary     0.736     1      NA Preprocessor1_Model2
4     2    17 accuracy binary     0.735     1      NA Preprocessor1_Model4
5     5     6 accuracy binary     0.731     1      NA Preprocessor1_Model1

# The model with mtry (number of predictors) is 7 has the best accuracy. 
# Hence the best model has mtry=7 and min_n=36

rf_best <- 
  rf_res %>% 
  select_best(metric = "accuracy")

# Display the best model
rf_best
# A tibble: 1 × 3
   mtry min_n .config             
  <int> <int> <chr>               
1     7    36 Preprocessor1_Model3


rf_res %>% 
  collect_predictions()
   id         .pred_class  .row  mtry min_n .pred_0  .pred_1 isWinner .config             
   <chr>      <fct>       <int> <int> <int>   <dbl>    <dbl> <fct>    <chr>               
 1 validation 1               1     5     6 0.497   0.503    0        Preprocessor1_Model1
 2 validation 1               9     5     6 0.00753 0.992    1        Preprocessor1_Model1
 3 validation 0              10     5     6 0.627   0.373    0        Preprocessor1_Model1
 4 validation 0              16     5     6 0.998   0.002    0        Preprocessor1_Model1
 5 validation 1              18     5     6 0.270   0.730    1        Preprocessor1_Model1
 6 validation 0              23     5     6 0.899   0.101    0        Preprocessor1_Model1
 7 validation 1              26     5     6 0.452   0.548    1        Preprocessor1_Model1
 8 validation 0              30     5     6 0.657   0.343    1        Preprocessor1_Model1
 9 validation 0              34     5     6 0.576   0.424    0        Preprocessor1_Model1
10 validation 0              35     5     6 1.00    0.000167 0        Preprocessor1_Model1

rf_auc <- 
  rf_res %>% 
  collect_predictions(parameters = rf_best) %>% 
  roc_curve(isWinner, .pred_0) %>% 
  mutate(model = "Random Forest")

autoplot(rf_auc)

I

The Final Model

# Create the final Random Forest model with mtry=7 and min_n=36
# engine as "ranger" for classification
last_rf_mod <- 
  rand_forest(mtry = 7, min_n = 36, trees = 1000) %>% 
  set_engine("ranger", num.threads = cores, importance = "impurity") %>% 
  set_mode("classification")


# the last workflow is updated with the final model
last_rf_workflow <- 
  rf_workflow %>% 
  update_model(last_rf_mod)

set.seed(345)
last_rf_fit <- 
  last_rf_workflow %>% 
  last_fit(splits)

# Collect metrics
last_rf_fit %>% 
  collect_metrics()
  .metric  .estimator .estimate .config             
  <chr>    <chr>          <dbl> <chr>               
1 accuracy binary         0.739 Preprocessor1_Model1
2 roc_auc  binary         0.837 Preprocessor1_Model1

The Random Forest model gives an accuracy of 0.739 and ROC_AUC of .837 which I think is quite good. This is roughly what I got with Tensorflow/Keras

# Get the feature importance 
last_rf_fit %>% 
  extract_fit_parsnip() %>% 
  vip(num_features = 7)

Interestingly the feature that I engineered seems to have the maximum importancce namely Performance Index which is a product of Run rate x Wicket in Hand. I would have thought numWickets would be important but in T20 match probably is is not.

 generate predictions from the test set
test_predictions <- last_rf_fit %>% collect_predictions()
> test_predictions
# A tibble: 241,182 × 7
id               .pred_0 .pred_1  .row .pred_class isWinner .config             
<chr>              <dbl>   <dbl> <int> <fct>       <fct>    <chr>               
  1 train/test split   0.496   0.504     1 1           0        Preprocessor1_Model1
2 train/test split   0.640   0.360    11 0           0        Preprocessor1_Model1
3 train/test split   0.596   0.404    14 0           0        Preprocessor1_Model1
4 train/test split   0.287   0.713    22 1           0        Preprocessor1_Model1
5 train/test split   0.616   0.384    28 0           0        Preprocessor1_Model1
6 train/test split   0.516   0.484    36 0           0        Preprocessor1_Model1
7 train/test split   0.754   0.246    37 0           0        Preprocessor1_Model1
8 train/test split   0.641   0.359    39 0           0        Preprocessor1_Model1
9 train/test split   0.811   0.189    40 0           0        Preprocessor1_Model1
10 train/test split   0.618   0.382    42 0           0        Preprocessor1_Model1


# generate a confusion matrix
test_predictions %>% 
  conf_mat(truth = isWinner, estimate = .pred_class)

          Truth
Prediction     0     1
         0 92173 31623
         1 31320 86066

# Create the final model on the train/test data
final_model <- fit(last_rf_workflow, df_other)

# Final model
final_model
══ Workflow [trained] ════════════════════════════════════════════════════════════════════════════════════════════════════════
Preprocessor: Recipe
Model: rand_forest()

── Preprocessor ──────────────────────────────────────────────────────────────────────────────────────────────────────────────
1 Recipe Step

• step_normalize()

── Model ─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
Ranger result

Call:
 ranger::ranger(x = maybe_data_frame(x), y = y, mtry = min_cols(~7,      x), num.trees = ~1000, min.node.size = min_rows(~36, x),      num.threads = ~cores, importance = ~"impurity", verbose = FALSE,      seed = sample.int(10^5, 1), probability = TRUE) 

Type:                             Probability estimation 
Number of trees:                  1000 
Sample size:                      964727 
Number of independent variables:  7 
Mtry:                             7 
Target node size:                 36 
Variable importance mode:         impurity 
Splitrule:                        gini 
OOB prediction error (Brier s.):  0.1631303

The Random Forest Model’s performance has been quite impressive and probably requires further exploration.

# Saving and loading the model
save(final_model, file = "fit.rda")
load("fit.rda")

#Predicting the Win Probability of CSK vs DD match on 12 May 2012

Comparing this with the Worm wicket graph of this match we see that DD had no chance at all

C) Win Probability with Tensorflow/Keras with Grid Search – Python

I spent a fair amount of time tuning the hyper parameters of the Keras Deep Learning Network. Finally did go for the Grid Search. Incidentally I did ask ChatGPT to suggest code snippets for GridSearch which it promptly did!!!

import pandas as pd
import numpy as np
from zipfile import ZipFile
import tensorflow as tf
from tensorflow import keras
from tensorflow.keras import layers
from tensorflow.keras import regularizers
from sklearn.model_selection import GridSearchCV

# Define the model
def create_model(optimizer='adam'):
    tf.random.set_seed(4)
    model = tf.keras.Sequential([
        keras.layers.Dense(32, activation=tf.nn.relu, input_shape=[len(train_dataset1.keys())]),
        keras.layers.Dense(16, activation=tf.nn.relu),
        keras.layers.Dense(8, activation=tf.nn.relu),
        keras.layers.Dense(1,activation=tf.nn.sigmoid)
    ])

    # Since this is binary classification use binary_crossentropy
    model.compile(loss='binary_crossentropy',
                    optimizer=optimizer,
                    metrics='accuracy')
    return(model)

    # Create a KerasClassifier object
model = keras.wrappers.scikit_learn.KerasClassifier(build_fn=create_model)

# Define the grid of hyperparameters to search over
batch_size = [1024]
epochs = [40]
learning_rate = [0.01, 0.001, 0.0001]
optimizer = ['SGD', 'RMSprop', 'Adagrad', 'Adadelta', 'Adam', 'Adamax', 'Nadam']

param_grid = dict(dict(optimizer=optimizer,batch_size=batch_size, epochs=epochs) )
# Create the grid search object
grid_search = GridSearchCV(estimator=model, param_grid=param_grid, cv=3)

# Fit the grid search object to the training data
grid_search.fit(normalized_train_data, train_labels)

# Print the best hyperparameters
print('Best hyperparameters:', grid_search.best_params_)
# summarize results
print("Best: %f using %s" % (grid_search.best_score_, grid_search.best_params_))
means = grid_search.cv_results_['mean_test_score']
stds = grid_search.cv_results_['std_test_score']
params = grid_search.cv_results_['params']
for mean, stdev, param in zip(means, stds, params):
    print("%f (%f) with: %r" % (mean, stdev, param))

The best worked out to be the optimiser ‘Nadam’ with a learning rate of 0.001

import matplotlib.pyplot as plt
# Create a model
tf.random.set_seed(4)
model = tf.keras.Sequential([
    keras.layers.Dense(32, activation=tf.nn.relu, input_shape=[len(train_dataset1.keys())]),
    keras.layers.Dense(16, activation=tf.nn.relu),
    keras.layers.Dense(8, activation=tf.nn.relu),
    keras.layers.Dense(1,activation=tf.nn.sigmoid)
  ])

# Use the Nadam optimiser
optimizer=keras.optimizers.Nadam(learning_rate=.001, beta_1=0.9, beta_2=0.999, epsilon=1e-07, decay=0.0)

# Since this is binary classification use binary_crossentropy
model.compile(loss='binary_crossentropy',
                optimizer=optimizer,
                metrics='accuracy')

# Fit 
#history=model.fit(
#  train_dataset1, train_labels,batch_size=1024,
#  epochs=40, validation_data=(test_dataset1,test_labels), verbose=1)
history=model.fit(
  normalized_train_data, train_labels,batch_size=1024,
  epochs=40, validation_data=(normalized_test_data,test_labels), verbose=1)

Epoch 37/40
943/943 [==============================] - 3s 3ms/step - loss: 0.4971 - accuracy: 0.7310 - val_loss: 0.4968 - val_accuracy: 0.7357
Epoch 38/40
943/943 [==============================] - 3s 3ms/step - loss: 0.4970 - accuracy: 0.7310 - val_loss: 0.4974 - val_accuracy: 0.7378
Epoch 39/40
943/943 [==============================] - 4s 4ms/step - loss: 0.4970 - accuracy: 0.7309 - val_loss: 0.4994 - val_accuracy: 0.7296
Epoch 40/40
943/943 [==============================] - 3s 3ms/step - loss: 0.4969 - accuracy: 0.7311 - val_loss: 0.4998 - val_accuracy: 0.7300
plt.plot(history.history["loss"])
plt.plot(history.history["val_loss"])
plt.title("model loss")
plt.ylabel("loss")
plt.xlabel("epoch")
plt.legend(["train", "test"], loc="upper left")
plt.show()

Conclusion

So, the Keras Deep Learning Network gives about the same performance of Random Forest in Tidy Models. But I went with R Random Forest as it was easier to save and load the model for use with my data. Also, I am not sure whether the performance of the ML model can be improved beyond a point. However, I will continue to explore.

Watch this space!!!

Also see

  1. Natural language processing: What would Shakespeare say?
  2. Revisiting World Bank data analysis with WDI and gVisMotionChart
  3. The mechanics of Convolutional Neural Networks in Tensorflow and Keras
  4. Deep Learning from first principles in Python, R and Octave – Part 4
  5. Big Data-4: Webserver log analysis with RDDs, Pyspark, SparkR and SparklyR
  6. Latency, throughput implications for the Cloud
  7. Practical Machine Learning with R and Python – Part 4
  8. Pitching yorkpy…swinging away from the leg stump to IPL – Part 3
  9. Experiments with deblurring using OpenCV
  10. Design Principles of Scalable, Distributed Systems

To see all posts click Index of posts

References

  1. White Ball Analytics
  2. Twenty20 Win Probability Added
  3. Tidy models – A predictive modeling case study
  4. Tidymodels: tidy machine learning in R
  5. A gentle introduction to Tidy models
  6. How to Grid Search Hyperparameters for Deep Learning Models in Python with Keras
  7. ChatGPT

Using embeddings, collaborative filtering with Deep Learning to analyse T20 players

There is a school of thought which considers that total runs scored and strike rate for a batsman, or total wickets taken and economy rate for a bowler, do not tell the whole story. This is true to a fair extent. The runs scored or the wickets taken could have been against weaker teams and hence the runs, strike rate or the wickets and economy rate alone do not capture all the performance details of the batsman or bowler. A technique to determine the performance of batsmen against different bowlers and identify the batsman’s possible performance even against bowlers he/she has not yet faced could be done with collaborative filtering. Collaborative filtering, with embeddings can also be used to group players with similar characteristics. Similarly, we could also identify the performance of bowlers versus different batsmen. Hence we need to look at average runs, SR and total wickets, ER with the lens of batsmen, bowlers against similar opposition. This is where collaborative filtering is useful.

The table below shows the performance of all batsman against all bowlers in the table below. The row in the table below is the batsman and the column is the bowler, with the value in the cell is the total Runs scored by the batsman against the bowler in all matches. Note the values are 0 for batsmen who have not yet faced specific bowlers. The table is fairly sparse.

Table A

Similarly, we can compute the performance of all bowlers against all batsmen as in the table below. Here the row is the bowler, the column batsman and the value in the cell is the number of times the bowler got the batsman’s wicket. As before the data is sparsely populated

This problem of computing batsman’s performance against bowlers or vice versa, is identical to the user vs movie rating problem used in collaborative filtering. For e.g we could consider

This above problem depicted could be computed using collaborative filtering with embeddings. We could assign sequential numbers for the batsmen from 1 to M, and for the bowlers from 1 to N. The total runs scored could be represented only for the rows where there are values. One way to solve this problem in Machine Learning is to use One Hot Encoding (OHE), where we assign values for each row and each column and map the values of the table with values of the cell for each combination. But this would take a enormous computation time and memory. The solution to this is use vector embeddings. Here embeddings could be used for capturing the sparse tensors between the batsmen, bowlers, runs scored or vice versa between bowlers against batsmen and the wickets taken. We only need to consider the cells for which values exist. An embedding is a relatively low-dimensional space, into which you can translate high-dimensional vectors. An embedding captures some of the semantics of the input by placing semantically similar inputs close together in the embedding space.

a) To compute bowler performances and identify similarities between bowlers the following embedding in the Deep Learning Network was used

To compute batsmen similarities a similar Deep Learning network for bowler vs batsmen is used

I had earlier created another post Player Performance Estimation using AI Collaborative Filtering for batsman and bowler recommendation, using R package Recommender Lab. However, I was not too happy with the results I got with this R package. When I searched the net for material on using embeddings for collaborative filtering, most of material on the web on movie lens or word2vec are repetitive and have no new material. Finally, this short video lecture from Developer Google on Embeddings provided the most clarity.

I have created 4 Colab notebooks to identify player similarities (recommendations)

a) Batsman similarities IPL

b) Batsman similarities T20

c) Bowler similarities IPL

d) Bowler similarities T20

For creating the model I have used all the data for T20 and IPL from so that I get the best results. The data is from Cricsheet. I have also used Google’s Embeddings Projector to display batsman and bowler embedding to and to group similar players

All the Colab notebooks and the data associated with the code are available in Github. Feel free to download and execute them. See if you get better performance. I tried a wide variety of hyperparameters – learning rate, width and depth of nodes per layer, number of layers, gradient methods etc.

You can download all the code & data from Github at embeddings

A) Batsman Recommender IPL (BatsmanRecommenderIPLA.ipynb)

Steps for creating the model

a) Upload bowler vs batsmen with times wicket was taken for batsman. This will be a sparse matrix

b) Assign integer indices for bowlers, batsmen

c) Add additional input features balls, runs conceded and Economy rate

d) Minimise loss for wickets taken for the bowler using SGD

e) Display embeddings of similar batsmen using Tensorboard projector

a) Upload data

Upload data file
2. Remove rows where wickets = 0

from google.colab import files
import io
uploaded = files.upload()
df2 = pd.read_csv(io.BytesIO(uploaded['bowlerVsBatsmanIPLE.csv']))
print(df2.shape)
df2 = df2.loc[df2['wicketTaken']!= 0]
print(df2.shape)

uploaded = files.upload()
df6 = pd.read_csv(io.BytesIO(uploaded['bowlerVsBatsmanIPLAll.csv']))
df6
     


Out[14]:

bowler1batsman1ballsrunsConcededER
0A Ashish ReddyDJG Sammy100.000000
1A Ashish ReddyG Gambhir101710.200000
2A Ashish ReddyJEC Franklin200.000000
3A Ashish ReddyLRPL Taylor567.200000
4A Ashish ReddyMA Agarwal3714.000000
8550Z KhanVishnu Vinod4812.000000
8551Z KhanVS Malik3510.000000
8552Z KhanW Jaffer732.571429
8553Z KhanYK Pathan22359.545455
8554Z KhanYuvraj Singh12126.000000

b) Create integer dictionaries for batsmen & bowlers

bowlers = df3["bowler1"].unique().tolist()
bowlers
# Create dictionary of bowler to index
bowlers2index = {x: i for i, x in enumerate(bowlers)}
bowlers2index
#Create dictionary of index tp bowler
index2bowlers = {i: x for i, x in enumerate(bowlers)}
index2bowlers


batsmen = df3["batsman1"].unique().tolist()
batsmen
# Create dictionary of batsman to index
batsmen2index = {x: i for i, x in enumerate(batsmen)}
batsmen2index
# Create dictionary of index to batsman
index2batsmen = {i: x for i, x in enumerate(batsmen)}
index2batsmen

#Map bowler, batsman to respective indices
df3["bowler"] = df3["bowler1"].map(bowlers2index)
df3["batsman"] = df3["batsman1"].map(batsmen2index)
df3
num_bowlers =len(bowlers2index)
num_batsmen = len(batsmen2index)
df3["wicketTaken"] = df3["wicketTaken"].values.astype(np.float32)
df3
# min and max ratings will be used to normalize the ratings later
min_wicketTaken = min(df3["wicketTaken"])
max_wicketTaken = max(df3["wicketTaken"])

print(
    "Number of bowlers: {}, Number of batsmen: {}, Min wicketsTaken: {}, Max wicketsTaken: {}".format(
        num_bowlers, num_batsmen, min_wicketTaken, max_wicketTaken
    )
)

c) Concatenate additional features

df3
df6
df31=pd.concat([df3,df6],axis=1)
df31

d) Create a Tensorflow/Keras deep learning mode. Minimise using Mean Squared Error using Stochastic Gradient Descent. I used ‘dropouts’ to regularise the model to keep validation loss within limits

tf.random.set_seed(4)
vector_size=len(batsmen2index)

df4=df31[['bowler','batsman','wicketTaken','balls','runsConceded','ER']]
df4
train_dataset = df4.sample(frac=0.9,random_state=0)
test_dataset = df4.drop(train_dataset.index)

train_dataset1 = train_dataset[['bowler','batsman','balls','runsConceded','ER']]
test_dataset1 = test_dataset[['bowler','batsman','balls','runsConceded','ER']]
train_stats = train_dataset1.describe()
train_stats = train_stats.transpose()
#print(train_stats)

train_labels = train_dataset.pop('wicketTaken')
test_labels = test_dataset.pop('wicketTaken')

# Create a Deep Learning model with keras
model = tf.keras.Sequential([
    tf.keras.layers.Embedding(vector_size,16,input_length=5),
    tf.keras.layers.Flatten(),
    keras.layers.Dropout(.2),
    keras.layers.Dense(16),
 
    keras.layers.Dense(8,activation=tf.nn.relu),
    
    keras.layers.Dense(4,activation=tf.nn.relu),
    keras.layers.Dense(1)
  ])

# Print the model summary
#model.summary()
# Use the Adam optimizer with a learning rate of 0.01
#optimizer=keras.optimizers.Adam(learning_rate=.0009, beta_1=0.5, beta_2=0.999, epsilon=None, decay=0.0, amsgrad=True)
#optimizer=keras.optimizers.RMSprop(learning_rate=0.01, rho=0.2, momentum=0.2, epsilon=1e-07)
#optimizer=keras.optimizers.SGD(learning_rate=.009,momentum=0.1) - Works without dropout
optimizer=keras.optimizers.SGD(learning_rate=.01,momentum=0.1)

model.compile(loss='mean_squared_error',
                optimizer=optimizer,
                )

 # Setup the training parameters
#model.compile(loss='binary_crossentropy',optimizer='rmsprop',metrics=['accuracy'])
# Create a model
history=model.fit(
  train_dataset1, train_labels,batch_size=32,
  epochs=40, validation_data = (test_dataset1,test_labels), verbose=1)

e) Plot losses

f) Predict wickets that will be taken by bowlers against random batsmen


df5= df4[['bowler','batsman','balls','runsConceded','ER']]
test1 = df5.sample(n=10)
test1.shape
for i in range(test1.shape[0]):
      print('Bowler :', index2bowlers.get(test1.iloc[i,0]), ", Batsman : ",index2batsmen.get(test1.iloc[i,1]), '- Times wicket Prediction:',model.predict(test1.iloc[[i]]))
1/1 [==============================] - 0s 90ms/step
Bowler : Harbhajan Singh , Batsman :  AM Nayar - Times wicket Prediction: [[1.0114906]]
1/1 [==============================] - 0s 18ms/step
Bowler : T Natarajan , Batsman :  Arshdeep Singh - Times wicket Prediction: [[0.98656166]]
1/1 [==============================] - 0s 19ms/step
Bowler : KK Ahmed , Batsman :  A Mishra - Times wicket Prediction: [[1.0504484]]
1/1 [==============================] - 0s 24ms/step
Bowler : M Muralitharan , Batsman :  F du Plessis - Times wicket Prediction: [[1.0941994]]
1/1 [==============================] - 0s 25ms/step
Bowler : SK Warne , Batsman :  DR Smith - Times wicket Prediction: [[1.0679393]]
1/1 [==============================] - 0s 28ms/step
Bowler : Mohammad Nabi , Batsman :  Ishan Kishan - Times wicket Prediction: [[1.403399]]
1/1 [==============================] - 0s 32ms/step
Bowler : R Bhatia , Batsman :  DJ Thornely - Times wicket Prediction: [[0.89399755]]
1/1 [==============================] - 0s 26ms/step
Bowler : SP Narine , Batsman :  MC Henriques - Times wicket Prediction: [[1.1997008]]
1/1 [==============================] - 0s 19ms/step
Bowler : AS Rajpoot , Batsman :  K Gowtham - Times wicket Prediction: [[0.9911405]]
1/1 [==============================] - 0s 21ms/step
Bowler : K Rabada , Batsman :  P Simran Singh - Times wicket Prediction: [[1.0064855]]

g) The embedding can be visualised using Google’s Embedding Projector, which identifies other batsmen who have similar characteristics. Here Cosine Similarity is used for grouping similar batsmen of IPL

The closest neighbor for AB De Villiers in IPL is SK Raina, then Rohit Sharma as seen in the visualisation below

B. Bowler Recommender T20 (BowlerRecommenderT20M1A.ipynb)

Similar to how batsman was set up,

The steps are

a) Upload data for T20 Batsman vs Bowler with Total runs scored. This will be a sparse matrix

b) Create integer dictionaries for batsman & bowler

c) Add additional features like fours, sixes and strike rate

d) Minimise loss for wicket taken

e) Display embeddings of bowlers using Tensorboard Embeddings Projector

Minimizing the loss for wicket taken using SGD

tf.random.set_seed(4)
vector_size=len(batsman2index)

#Normalize target variable
df4=df31[['bowler','batsman','totalRuns','fours','sixes','ballsFaced']]
df4['normalizedRuns'] = (df4['totalRuns'] -df4['totalRuns'].mean())/df4['totalRuns'].std()
print(df4)
train_dataset = df4.sample(frac=0.8,random_state=0)
test_dataset = df4.drop(train_dataset.index)
train_dataset1 = train_dataset[['batsman','bowler','fours','sixes','ballsFaced']]
test_dataset1 = test_dataset[['batsman','bowler','fours','sixes','ballsFaced']]

train_labels = train_dataset.pop('normalizedRuns')
test_labels = test_dataset.pop('normalizedRuns')
train_labels
print(train_dataset1)

# Create a Deep Learning model with keras
model = tf.keras.Sequential([
    tf.keras.layers.Embedding(vector_size,16,input_length=5),
    tf.keras.layers.Flatten(),
    keras.layers.Dropout(.2),
    keras.layers.Dense(16),
 
    keras.layers.Dense(8,activation=tf.nn.relu),
    
    keras.layers.Dense(4,activation=tf.nn.relu),
    keras.layers.Dense(1)
  ])

# Print the model summary
#model.summary()
# Use the Adam optimizer with a learning rate of 0.01
#optimizer=keras.optimizers.Adam(learning_rate=.0009, beta_1=0.5, beta_2=0.999, epsilon=None, decay=0.0, amsgrad=True)
#optimizer=keras.optimizers.RMSprop(learning_rate=0.001, rho=0.2, momentum=0.2, epsilon=1e-07)
#optimizer=keras.optimizers.SGD(learning_rate=.009,momentum=0.1) - Works without dropout
optimizer=keras.optimizers.SGD(learning_rate=.01,momentum=0.1)

model.compile(loss='mean_squared_error',
                optimizer=optimizer,
                )

 # Setup the training parameters
#model.compile(loss='binary_crossentropy',optimizer='rmsprop',metrics=['accuracy'])
# Create a model
history=model.fit(
  train_dataset1, train_labels,batch_size=32,
  epochs=40, validation_data = (test_dataset1,test_labels), verbose=1)
model.predict(train_dataset1[1:10])
df5= df4[['batsman','bowler','fours','sixes','ballsFaced']]
test1 = df5.sample(n=10)
model.predict(test1)
#(model.predict(test1)* df4['totalRuns'].std()) + df4['totalRuns'].mean()
for i in range(test1.shape[0]):
        print('Batsman :', index2batsman.get(test1.iloc[i,0]), ", Bowler : ",index2bowler.get(test1.iloc[i,1]), '- Total runs Prediction:',(model.predict(test1.iloc[i])* df4['totalRuns'].std()) + df4['totalRuns'].mean())
1/1 [==============================] - 0s 396ms/step
1/1 [==============================] - 0s 112ms/step
1/1 [==============================] - 0s 183ms/step
Batsman : G Chohan , Bowler :  Khawar Ali - Total runs Prediction: [[1.8883028]]
1/1 [==============================] - 0s 56ms/step
Batsman : Umar Akmal , Bowler :  LJ Wright - Total runs Prediction: [[9.305391]]
1/1 [==============================] - 0s 68ms/step
Batsman : M Shumba , Bowler :  Simi Singh - Total runs Prediction: [[19.662743]]
1/1 [==============================] - 0s 30ms/step
Batsman : CH Gayle , Bowler :  RJW Topley - Total runs Prediction: [[16.854687]]
1/1 [==============================] - 0s 39ms/step
Batsman : BA King , Bowler :  Taskin Ahmed - Total runs Prediction: [[3.5154686]]
1/1 [==============================] - 0s 102ms/step
Batsman : KD Shah , Bowler :  Avesh Khan - Total runs Prediction: [[8.411661]]
1/1 [==============================] - 0s 38ms/step
Batsman : ST Jayasuriya , Bowler :  SCJ Broad - Total runs Prediction: [[5.867449]]
1/1 [==============================] - 0s 45ms/step
Batsman : AB de Villiers , Bowler :  Saeed Ajmal - Total runs Prediction: [[15.150892]]
1/1 [==============================] - 0s 46ms/step
Batsman : SV Samson , Bowler :  J Little - Total runs Prediction: [[10.44426]]
1/1 [==============================] - 0s 102ms/step
Batsman : Zawar Farid , Bowler :  GJ Delany - Total runs Prediction: [[1.9770675]]

Identifying similar bowlers using Embeddings Projector for T20

Bhuvaneshwar Kumar’s performance is closest to CR Woakes

Note: Incidentally the accuracy in the above model was not too good. I may work on this again later!

C) Bowler Embeddings IPL – Grouping similar bowlers of IPL with Embeddings Projector (BowlerRecommenderIPLA.ipynb)

D) Batting Embeddings T20 – Grouping similar batsmen of T20 (BatsmanRecommenderT20MA.ipynb)

The Tensorboard Pmbeddings projector is also interesting. There are multiple ways the data can be visualised namely UMAP, T-SNE, PCA(included). You could play with it.

As mentioned above the Colab notebooks and data are available at Github embeddings

The ability to identify batsmen & bowlers who would perform similarly against specific bowling attacks coupled with the average runs & strike rate should give a good measure of a player’s performance.

Take a look at some of my other posts

  1. Using Reinforcement Learning to solve Gridworld
  2. Deep Learning from first principles in Python, R and Octave – Part 4
  3. Big Data 7: yorkr waltzes with Apache NiFi
  4. Programming languages in layman’s language
  5. Pitching yorkpy…swinging away from the leg stump to IPL – Part 3
  6. Re-introducing cricketr! : An R package to analyze performances of cricketers
  7. The making of Total Control Android game
  8. Presentation on “Intelligent Networks, CAMEL protocol, services & applications”
  9. Exploring Quantum Gate operations with QCSimulator

To see all posts click Index of posts

Deconstructing Convolutional Neural Networks with Tensorflow and Keras

I have been very fascinated by how Convolution Neural  Networks have been able to, so efficiently,  do image classification and image recognition CNN’s have been very successful in in both these tasks. A good paper that explores the workings of a CNN Visualizing and Understanding Convolutional Networks  by Matthew D Zeiler and Rob Fergus. They show how through a reverse process of convolution using a deconvnet.

In their paper they show how by passing the feature map through a deconvnet ,which does the reverse process of the convnet, they can reconstruct what input pattern originally caused a given activation in the feature map

In the paper they say “A deconvnet can be thought of as a convnet model that uses the same components (filtering, pooling) but in reverse, so instead of mapping pixels to features, it does the opposite. An input image is presented to the CNN and features  activation computed throughout the layers. To examine a given convnet activation, we set all other activations in the layer to zero and pass the feature maps as input to the attached deconvnet layer. Then we successively (i) unpool, (ii) rectify and (iii) filter to reconstruct the activity in the layer beneath that gave rise to the chosen activation. This is then repeated until input pixel space is reached.”

I started to scout the internet to see how I can implement this reverse process of Convolution to understand what really happens under the hood of a CNN.  There are a lot of good articles and blogs, but I found this post Applied Deep Learning – Part 4: Convolutional Neural Networks take the visualization of the CNN one step further.

This post takes VGG16 as the pre-trained network and then uses this network to display the intermediate visualizations.  While this post was very informative and also the visualizations of the various images were very clear, I wanted to simplify the problem for my own understanding.

Hence I decided to take the MNIST digit classification as my base problem. I created a simple 3 layer CNN which gives close to 99.1% accuracy and decided to see if I could do the visualization.

As mentioned in the above post, there are 3 major visualisations

  1. Feature activations at the layer
  2. Visualisation of the filters
  3. Visualisation of the class outputs

Feature Activation – This visualization the feature activation at the 3 different layers for a given input image. It can be seen that first layer  activates based on the edge of the image. Deeper layers activate in a more abstract way.

Visualization of the filters: This visualization shows what patterns the filters respond maximally to. This is implemented in Keras here

To do this the following is repeated in a loop

  • Choose a loss function that maximizes the value of a convnet filter activation
  • Do gradient ascent (maximization) in input space that increases the filter activation

Visualizing Class Outputs of the MNIST Convnet: This process is similar to determining the filter activation. Here the convnet is made to generate an image that represents the category maximally.

You can access the Google colab notebook here – Deconstructing Convolutional Neural Networks in Tensoflow and Keras

import numpy as np
import pandas as pd
import os
import tensorflow as tf
import matplotlib.pyplot as plt
from keras.layers import Dense, Dropout, Flatten
from keras.layers import Conv2D, MaxPooling2D, Input
from keras.models import Model
from sklearn.model_selection import train_test_split
from keras.utils import np_utils
Using TensorFlow backend.
In [0]:
mnist=tf.keras.datasets.mnist
# Set training and test data and labels
(training_images,training_labels),(test_images,test_labels)=mnist.load_data()
In [0]:
#Normalize training data
X =np.array(training_images).reshape(training_images.shape[0],28,28,1) 
# Normalize the images by dividing by 255.0
X = X/255.0
X.shape
# Use one hot encoding for the labels
Y = np_utils.to_categorical(training_labels, 10)
Y.shape
# Split training data into training and validation data in the ratio of 80:20
X_train, X_validation, y_train, y_validation = train_test_split(X,Y,test_size=0.20, random_state=42)
In [4]:
# Normalize test data
X_test =np.array(test_images).reshape(test_images.shape[0],28,28,1) 
X_test=X_test/255.0
#Use OHE for the test labels
Y_test = np_utils.to_categorical(test_labels, 10)
X_test.shape
Out[4]:
(10000, 28, 28, 1)

Display data

Display the training data and the corresponding labels

In [5]:
print(training_labels[0:10])
f, axes = plt.subplots(1, 10, sharey=True,figsize=(10,10))
for i,ax in enumerate(axes.flat):
    ax.axis('off')
    ax.imshow(X[i,:,:,0],cmap="gray")

Create a Convolutional Neural Network

The CNN consists of 3 layers

  • Conv2D of size 28 x 28 with 24 filters
  • Perform Max pooling
  • Conv2D of size 14 x 14 with 48 filters
  • Perform max pooling
  • Conv2d of size 7 x 7 with 64 filters
  • Flatten
  • Use Dense layer with 128 units
  • Perform 25% dropout
  • Perform categorical cross entropy with softmax activation function
In [0]:
num_classes=10
inputs = Input(shape=(28,28,1))
x = Conv2D(24,kernel_size=(3,3),padding='same',activation="relu")(inputs)
x = MaxPooling2D(pool_size=(2, 2))(x)
x = Conv2D(48, (3, 3), padding='same',activation='relu')(x)
x = MaxPooling2D(pool_size=(2, 2))(x)
x = Conv2D(64, (3, 3), padding='same',activation='relu')(x)
x = MaxPooling2D(pool_size=(2, 2))(x)
x = Flatten()(x)
x = Dense(128, activation='relu')(x)
x = Dropout(0.25)(x)
output = Dense(num_classes,activation="softmax")(x)

model = Model(inputs,output)

model.compile(loss='categorical_crossentropy', 
          optimizer='adam', 
          metrics=['accuracy'])

Summary of CNN

Display the summary of CNN

In [7]:
model.summary()
Model: "model_1"
_________________________________________________________________
Layer (type)                 Output Shape              Param #   
=================================================================
input_1 (InputLayer)         (None, 28, 28, 1)         0         
_________________________________________________________________
conv2d_1 (Conv2D)            (None, 28, 28, 24)        240       
_________________________________________________________________
max_pooling2d_1 (MaxPooling2 (None, 14, 14, 24)        0         
_________________________________________________________________
conv2d_2 (Conv2D)            (None, 14, 14, 48)        10416     
_________________________________________________________________
max_pooling2d_2 (MaxPooling2 (None, 7, 7, 48)          0         
_________________________________________________________________
conv2d_3 (Conv2D)            (None, 7, 7, 64)          27712     
_________________________________________________________________
max_pooling2d_3 (MaxPooling2 (None, 3, 3, 64)          0         
_________________________________________________________________
flatten_1 (Flatten)          (None, 576)               0         
_________________________________________________________________
dense_1 (Dense)              (None, 128)               73856     
_________________________________________________________________
dropout_1 (Dropout)          (None, 128)               0         
_________________________________________________________________
dense_2 (Dense)              (None, 10)                1290      
=================================================================
Total params: 113,514
Trainable params: 113,514
Non-trainable params: 0
_________________________________________________________________

Perform Gradient descent and validate with the validation data

In [8]:
epochs = 20
batch_size=256
history = model.fit(X_train,y_train,
         epochs=epochs,
         batch_size=batch_size,
         validation_data=(X_validation,y_validation))
————————————————
acc = history.history[ ‘accuracy’ ]
val_acc = history.history[ ‘val_accuracy’ ]
loss = history.history[ ‘loss’ ]
val_loss = history.history[‘val_loss’ ]
epochs = range(len(acc)) # Get number of epochs
#————————————————
# Plot training and validation accuracy per epoch
#————————————————
plt.plot ( epochs, acc,label=”training accuracy” )
plt.plot ( epochs, val_acc, label=’validation acuracy’ )
plt.title (‘Training and validation accuracy’)
plt.legend()
plt.figure()
#————————————————
# Plot training and validation loss per epoch
#————————————————
plt.plot ( epochs, loss , label=”training loss”)
plt.plot ( epochs, val_loss,label=”validation loss” )
plt.title (‘Training and validation loss’ )
plt.legend()
Test model on test data
f, axes = plt.subplots(1, 10, sharey=True,figsize=(10,10))
for i,ax in enumerate(axes.flat):
ax.axis(‘off’)
ax.imshow(X_test[i,:,:,0],cmap=”gray”)
l=[]
for i in range(10):
  x=X_test[i].reshape(1,28,28,1)
  y=model.predict(x)
  m = np.argmax(y, axis=1)
  print(m)
[7]
[2]
[1]
[0]
[4]
[1]
[4]
[9]
[5]
[9]

Generate the filter activations at the intermediate CNN layers

In [12]:
img = test_images[51].reshape(1,28,28,1)
fig = plt.figure(figsize=(5,5))
print(img.shape)
plt.imshow(img[0,:,:,0],cmap="gray")
plt.axis('off')

Display the activations at the intermediate layers

This displays the intermediate activations as the image passes through the filters and generates these feature maps

In [13]:
layer_names = ['conv2d_4', 'conv2d_5', 'conv2d_6']

layer_outputs = [layer.output for layer in model.layers if 'conv2d' in layer.name]
activation_model = Model(inputs=model.input,outputs=layer_outputs)
intermediate_activations = activation_model.predict(img)
images_per_row = 8
max_images = 8

for layer_name, layer_activation in zip(layer_names, intermediate_activations):
    print(layer_name,layer_activation.shape)
    n_features = layer_activation.shape[-1]
    print("features=",n_features)
    n_features = min(n_features, max_images)
    print(n_features)

    size = layer_activation.shape[1]
    print("size=",size)
    n_cols = n_features // images_per_row
    display_grid = np.zeros((size * n_cols, images_per_row * size))


    for col in range(n_cols):
      for row in range(images_per_row):
          channel_image = layer_activation[0,:, :, col * images_per_row + row]

          channel_image -= channel_image.mean()
          channel_image /= channel_image.std()
          channel_image *= 64
          channel_image += 128
          channel_image = np.clip(channel_image, 0, 255).astype('uint8')
          display_grid[col * size : (col + 1) * size,
                         row * size : (row + 1) * size] = channel_image
    scale = 2. / size
    plt.figure(figsize=(scale * display_grid.shape[1],
                        scale * display_grid.shape[0]))
    plt.axis('off')
    plt.title(layer_name)
    plt.grid(False)
    plt.imshow(display_grid, aspect='auto', cmap='viridis')
    
plt.show()

It can be seen that at the higher layers only abstract features of the input image are captured
# To fix the ImportError: cannot import name 'imresize' in the next cell. Run this cell. Then comment and restart and run all
#!pip install scipy==1.1.0

Visualize the pattern that the filters respond to maximally

  • Choose a loss function that maximizes the value of the CNN filter in a given layer
  • Start from a blank input image.
  • Do gradient ascent in input space. Modify input values so that the filter activates more
  • Repeat this in a loop.
In [14]:
from vis.visualization import visualize_activation, get_num_filters
from vis.utils import utils
from vis.input_modifiers import Jitter

max_filters = 24
selected_indices = []
vis_images = [[], [], [], [], []]
i = 0
selected_filters = [[0, 3, 11, 15, 16, 17, 18, 22], 
    [8, 21, 23, 25, 31, 32, 35, 41], 
    [2, 7, 11, 14, 19, 26, 35, 48]]

# Set the layers
layer_name = ['conv2d_4', 'conv2d_5', 'conv2d_6']
# Set the layer indices
layer_idx = [1,3,5]
for layer_name,layer_idx in zip(layer_name,layer_idx):


    # Visualize all filters in this layer.
    if selected_filters:
        filters = selected_filters[i]
    else:
        # Randomly select filters
        filters = sorted(np.random.permutation(get_num_filters(model.layers[layer_idx]))[:max_filters])
    selected_indices.append(filters)

    # Generate input image for each filter.
    # Loop through the selected filters in each layer and generate the activation of these filters
    for idx in filters:
        img = visualize_activation(model, layer_idx, filter_indices=idx, tv_weight=0., 
                                   input_modifiers=[Jitter(0.05)], max_iter=300) 
        vis_images[i].append(img)

    # Generate stitched image palette with 4 cols so we get 2 rows.
    stitched = utils.stitch_images(vis_images[i], cols=4)    
    plt.figure(figsize=(20, 30))
    plt.title(layer_name)
    plt.axis('off')
    stitched = stitched.reshape(1,61,127,1)
    plt.imshow(stitched[0,:,:,0])
    plt.show()
    i += 1
from vis.utils import utils
new_vis_images = [[], [], [], [], []]
i = 0
layer_name = ['conv2d_4', 'conv2d_5', 'conv2d_6']
layer_idx = [1,3,5]
for layer_name,layer_idx in zip(layer_name,layer_idx):
   
    # Generate input image for each filter.
    for j, idx in enumerate(selected_indices[i]):
        img = visualize_activation(model, layer_idx, filter_indices=idx, 
                                   seed_input=vis_images[i][j], input_modifiers=[Jitter(0.05)], max_iter=300) 
        #img = utils.draw_text(img, 'Filter {}'.format(idx))  
        new_vis_images[i].append(img)

    stitched = utils.stitch_images(new_vis_images[i], cols=4)   
    plt.figure(figsize=(20, 30))
    plt.title(layer_name)
    plt.axis('off')
    print(stitched.shape)
    stitched = stitched.reshape(1,61,127,1)
    plt.imshow(stitched[0,:,:,0])
    plt.show()
    i += 1

Visualizing Class Outputs

Here the CNN will generate the image that maximally represents the category. Each of the output represents one of the digits as can be seen below

In [16]:
from vis.utils import utils
from keras import activations
codes = '''
zero 0
one 1
two 2
three 3
four 4
five 5
six 6
seven 7
eight 8
nine 9
'''
layer_idx=10
initial = []
images = []
tuples = []
# Swap softmax with linear for better visualization
model.layers[layer_idx].activation = activations.linear
model = utils.apply_modifications(model)
for line in codes.split('\n'):
    if not line:
        continue
    name, idx = line.rsplit(' ', 1)
    idx = int(idx)
    img = visualize_activation(model, layer_idx, filter_indices=idx, 
                               tv_weight=0., max_iter=300, input_modifiers=[Jitter(0.05)])

    initial.append(img)
    tuples.append((name, idx))

i = 0
for name, idx in tuples:
    img = visualize_activation(model, layer_idx, filter_indices=idx,
                               seed_input = initial[i], max_iter=300, input_modifiers=[Jitter(0.05)])
    #img = utils.draw_text(img, name) # Unable to display text on gray scale image
    i += 1
    images.append(img)

stitched = utils.stitch_images(images, cols=4)
plt.figure(figsize=(20, 20))
plt.axis('off')
stitched = stitched.reshape(1,94,127,1)
plt.imshow(stitched[0,:,:,0])

plt.show()

In the grid below the class outputs show the MNIST digits to which output responds to maximally. We can see the ghostly outline
of digits 0 – 9. We can clearly see the outline if 0,1, 2,3,4,5 (yes, it is there!),6,7, 8 and 9. If you look at this from a little distance the digits are clearly visible. Isn’t that really cool!!


 

Conclusion:


It is really interesting to see the class outputs which show the image to which the class output responds to maximally. In the
post Applied Deep Learning – Part 4: Convolutional Neural Networks the class output show much more complicated images and is worth a look. It is really interesting to note that the model has adjusted the filter values and the weights of the fully connected network to maximally respond to the MNIST digits

References

1. Visualizing and Understanding Convolutional Networks
2. Applied Deep Learning – Part 4: Convolutional Neural Networks
3. Visualizing Intermediate Activations of a CNN trained on the MNIST Dataset
4. How convolutional neural networks see the world
5. Keras – Activation_maximization

Also see

1. Using Reinforcement Learning to solve Gridworld
2. Deep Learning from first principles in Python, R and Octave – Part 8
3. Cricketr learns new tricks : Performs fine-grained analysis of players
4. Video presentation on Machine Learning, Data Science, NLP and Big Data – Part 1
5. Big Data-2: Move into the big league:Graduate from R to SparkR
6. OpenCV: Fun with filters and convolution
7. Powershell GUI – Adding bells and whistles

To see all posts click Index of posts

The mechanics of Convolutional Neural Networks in Tensorflow and Keras

Convolutional Neural Networks (CNNs), have been very popular in the last decade or so. CNNs have been used in multiple applications like image recognition, image classification, facial recognition, neural style transfer etc. CNN’s have been extremely successful in handling these kind of problems. How do they work? What makes them so successful? What is the principle behind CNN’s ?

Note: this post is based on two Coursera courses I did, namely namely Deep Learning specialisation by Prof Andrew Ng and Tensorflow Specialisation by  Laurence Moroney.

In this post I show you how CNN’s work. To understand how CNNs work, we need to understand the concept behind machine learning algorithms. If you take a simple machine learning algorithm in which you are trying to do multi-class classification using softmax or binary classification with the sigmoid function, for a set of for a set of input features against a target variable we need to create an objective function of the input features versus the target variable. Then we need to minimise this objective function, while performing gradient descent, such that the cost  is the lowest. This will give the set of weights for the different variables in the objective function.

The central problem in ML algorithms is to do feature selection, i.e.  we need to find the set of features that actually influence the target.  There are various methods for doing features selection – best fit, forward fit, backward fit, ridge and lasso regression. All these methods try to pick out the predictors that influence the output most, by making the weights of the other features close to zero. Please look at my post – Practical Machine Learning in R and Python – Part 3, where I show you the different methods for doing features selection.

In image classification or Image recognition we need to find the important features in the image. How do we do that? Many years back, have played around with OpenCV.  While working with OpenCV I came across are numerous filters like the Sobel ,the Laplacian, Canny, Gaussian filter et cetera which can be used to identify key features of the image. For example the Canny filter feature can be used for edge detection, Gaussian for smoothing, Sobel for determining the derivative and we have other filters for detecting vertical or horizontal edges. Take a look at my post Computer Vision: Ramblings on derivatives, histograms and contours So for handling images we need to apply these filters to pick  out the key features of the image namely the edges and other features. So rather than using the entire image’s pixels against the target class we can pick out the features from the image and use that as predictors of the target output.

Note: that in Convolutional Neural Network, fixed filter values like the those shown above  are not used directly. Rather the filter values are learned through back propagation and gradient descent as shown below.

In CNNs the filter values are considered to be weights which are then learned and updated in each forward/backward propagation cycle much like the way a fully connected Deep Learning Network learns the weights of the network.

Here is a short derivation of the most important parts of how a CNNs work

The convolution of a filter F with the input X can be represented as.

 

 

Convolving we get

 

This the forward propagation as it passes through a non-linear function like Relu

 

To go through back propagation we need to compute the \partial L  at every node of Convolutional Neural network

 

The loss with respect to the output is \partial L/\partial O. \partial O/\partial X & \partial O/\partial F are the local derivatives

We need these local derivatives because we can learn the filter values using gradient descent

where \alpha is the learning rate. Also \partial L/\partial X is the loss which is back propagated to the previous layers. You can see the detailed derivation of back propagation in my post Deep Learning from first principles in Python, R and Octave – Part 3 in a L-layer, multi-unit Deep Learning network.

In the fully connected layers the weights associated with each connection is computed in every cycle of forward and backward propagation using gradient descent. Similarly, the filter values are also computed and updated in each forward and backward propagation cycle. This is done so as to minimize the loss at the output layer.

By using the chain rule and simplifying the back propagation for the Convolutional layers we get these 2 equations. The first equation is used to learn the filter values and the second is used pass the loss to layers before

(for the detailed derivation see Convolutions and Backpropagations

An important aspect of performing convolutions is to reduce the size of  the flattened image that is passed into the fully connected DL network. Successively convolving with 2D filters and doing a max pooling helps to reduce the size of the features that we can use for learning the images. Convolutions also enable a sparsity of connections  as you can see in the diagram below. In the LeNet-5 Convolution Neural Network of Yann Le Cunn, successive convolutions reduce the image size from 28 x 28=784 to 120 flattened values.

Here is an interesting Deep Learning problem. Convolutions help in picking out important features of images and help in image classification/ detection. What would be its equivalent if we wanted to identify the Carnatic ragam of a song? A Carnatic ragam is roughly similar to Western scales (major, natural, melodic, blues) with all its modes Lydian, Aeolion, Phyrgian etc. Except in the case of the ragams, it is more nuanced, complex and involved. Personally, I can rarely identify a ragam on which a carnatic song is based (I am tone deaf when it comes to identifying ragams). I have come to understand that each Carnatic ragam has its own character, which is made up of several melodic phrases which are unique to that flavor of a ragam. What operation like convolution would be needed so that we can pick out these unique phrases in a Carnatic ragam? Of course, we would need to use it in Recurrent Neural Networks with LSTMs as a song is a time sequence of notes to identify sequences. Nevertheless, if there was some operation with which we can pick up the distinct, unique phrases from a song and then run it through a classifier, maybe we would be able to identify the ragam of the song.

Below I implement 3 simple CNN using the Dogs vs Cats Dataset from Kaggle. The first CNN uses regular Convolutions a Fully connected network to classify the images. The second approach uses Image Augmentation. For some reason, I did not get a better performance with Image Augumentation. Thirdly I use the pre-trained Inception v3 network.

 

1. Basic Convolutional Neural Network in Tensorflow & Keras

You can view the Colab notebook here – Cats_vs_dogs_1.ipynb

Here some important parts of the notebook

Create CNN Model

  • Use 3 Convolution + Max pooling layers with 32,64 and 128 filters respectively
  • Flatten the data
  • Have 2 Fully connected layers with 128, 512 neurons with relu activation
  • Use sigmoid for binary classification
In [0]:
model = tf.keras.models.Sequential([
    tf.keras.layers.Conv2D(32,(3,3),activation='relu',input_shape=(150,150,3)),
    tf.keras.layers.MaxPooling2D(2,2),
    tf.keras.layers.Conv2D(64,(3,3),activation='relu'),
    tf.keras.layers.MaxPooling2D(2,2),
    tf.keras.layers.Conv2D(128,(3,3),activation='relu'),
    tf.keras.layers.MaxPooling2D(2,2),
    tf.keras.layers.Flatten(),
    tf.keras.layers.Dense(128,activation='relu'),
    tf.keras.layers.Dense(512,activation='relu'),
    tf.keras.layers.Dense(1,activation='sigmoid')
])

Print model summary

In [13]:
model.summary()
Model: "sequential"
_________________________________________________________________
Layer (type)                 Output Shape              Param #   
=================================================================
conv2d (Conv2D)              (None, 148, 148, 32)      896       
_________________________________________________________________
max_pooling2d (MaxPooling2D) (None, 74, 74, 32)        0         
_________________________________________________________________
conv2d_1 (Conv2D)            (None, 72, 72, 64)        18496     
_________________________________________________________________
max_pooling2d_1 (MaxPooling2 (None, 36, 36, 64)        0         
_________________________________________________________________
conv2d_2 (Conv2D)            (None, 34, 34, 128)       73856     
_________________________________________________________________
max_pooling2d_2 (MaxPooling2 (None, 17, 17, 128)       0         
_________________________________________________________________
flatten (Flatten)            (None, 36992)             0         
_________________________________________________________________
dense (Dense)                (None, 128)               4735104   
_________________________________________________________________
dense_1 (Dense)              (None, 512)               66048     
_________________________________________________________________
dense_2 (Dense)              (None, 1)                 513       
=================================================================
Total params: 4,894,913
Trainable params: 4,894,913
Non-trainable params: 0
_________________________________________________________________

Use the Adam Optimizer with binary cross entropy

model.compile(optimizer='adam',
             loss='binary_crossentropy',
             metrics=['accuracy'])

Perform Gradient Descent

  • Do Gradient Descent for 15 epochs
history=model.fit(train_generator,
                 validation_data=validation_generator,
                 steps_per_epoch=100,
                 epochs=15,
                 validation_steps=50,
                 verbose=2)
Epoch 1/15
100/100 - 13s - loss: 0.6821 - accuracy: 0.5425 - val_loss: 0.6484 - val_accuracy: 0.6131
Epoch 2/15
100/100 - 13s - loss: 0.6227 - accuracy: 0.6456 - val_loss: 0.6161 - val_accuracy: 0.6394
Epoch 3/15
100/100 - 13s - loss: 0.5975 - accuracy: 0.6719 - val_loss: 0.5558 - val_accuracy: 0.7206
Epoch 4/15
100/100 - 13s - loss: 0.5480 - accuracy: 0.7241 - val_loss: 0.5431 - val_accuracy: 0.7138
Epoch 5/15
100/100 - 13s - loss: 0.5182 - accuracy: 0.7447 - val_loss: 0.4839 - val_accuracy: 0.7606
Epoch 6/15
100/100 - 13s - loss: 0.4773 - accuracy: 0.7781 - val_loss: 0.5029 - val_accuracy: 0.7506
Epoch 7/15
100/100 - 13s - loss: 0.4466 - accuracy: 0.7972 - val_loss: 0.4573 - val_accuracy: 0.7912
Epoch 8/15
100/100 - 13s - loss: 0.4395 - accuracy: 0.7997 - val_loss: 0.4252 - val_accuracy: 0.8119
Epoch 9/15
100/100 - 13s - loss: 0.4314 - accuracy: 0.8019 - val_loss: 0.4931 - val_accuracy: 0.7481
Epoch 10/15
100/100 - 13s - loss: 0.4309 - accuracy: 0.7969 - val_loss: 0.4203 - val_accuracy: 0.8109
Epoch 11/15
100/100 - 13s - loss: 0.4329 - accuracy: 0.7916 - val_loss: 0.4189 - val_accuracy: 0.8069
Epoch 12/15
100/100 - 13s - loss: 0.4248 - accuracy: 0.8050 - val_loss: 0.4476 - val_accuracy: 0.7925
Epoch 13/15
100/100 - 13s - loss: 0.3868 - accuracy: 0.8306 - val_loss: 0.3900 - val_accuracy: 0.8236
Epoch 14/15
100/100 - 13s - loss: 0.3710 - accuracy: 0.8328 - val_loss: 0.4520 - val_accuracy: 0.7900
Epoch 15/15
100/100 - 13s - loss: 0.3654 - accuracy: 0.8353 - val_loss: 0.3999 - val_accuracy: 0.8100

 

 

 

 

 

 

Plot results

    • Plot training and validation accuracy

 

  • Plot training and validation loss

 

 

 

 

 

 

#-----------------------------------------------------------
# Retrieve a list of list results on training and test data
# sets for each training epoch
#-----------------------------------------------------------
acc      = history.history[     'accuracy' ]
val_acc  = history.history[ 'val_accuracy' ]
loss     = history.history[    'loss' ]
val_loss = history.history['val_loss' ]

epochs   = range(len(acc)) # Get number of epochs

#------------------------------------------------
# Plot training and validation accuracy per epoch
#------------------------------------------------
plt.plot  ( epochs,     acc,label="training accuracy" )
plt.plot  ( epochs, val_acc, label='validation acuracy' )
plt.title ('Training and validation accuracy')
plt.legend()

plt.figure()

#------------------------------------------------
# Plot training and validation loss per epoch
#------------------------------------------------
plt.plot  ( epochs,     loss , label="training loss")
plt.plot  ( epochs, val_loss,label="validation loss" )
plt.title ('Training and validation loss'   )
plt.legend()



 

2. CNN with Image Augmentation

You can check the Cats_vs_Dogs_2.ipynb

Including the important parts of this implementation below

Use Image Augumentation

Use Image Augumentation to improve performance

  • Use the same model parameters as before
  • Perform the following image augmentation
    • width, height shift
    • shear and zoom

    Note: Adding rotation made the performance worse

import tensorflow as tf
from tensorflow import keras
from tensorflow.keras.optimizers import RMSprop
from tensorflow.keras.preprocessing.image import ImageDataGenerator
model = tf.keras.models.Sequential([
    tf.keras.layers.Conv2D(32,(3,3),activation='relu',input_shape=(150,150,3)),
    tf.keras.layers.MaxPooling2D(2,2),
    tf.keras.layers.Conv2D(64,(3,3),activation='relu'),
    tf.keras.layers.MaxPooling2D(2,2),
    tf.keras.layers.Conv2D(128,(3,3),activation='relu'),
    tf.keras.layers.MaxPooling2D(2,2),
    tf.keras.layers.Flatten(),
    tf.keras.layers.Dense(128,activation='relu'),
    tf.keras.layers.Dense(512,activation='relu'),
    tf.keras.layers.Dense(1,activation='sigmoid')
])


train_datagen = ImageDataGenerator(
      rescale=1./255,
      #rotation_range=90,
      width_shift_range=0.2,
      height_shift_range=0.2,
      shear_range=0.2,
      zoom_range=0.2)
      #horizontal_flip=True,
      #fill_mode='nearest')

validation_datagen = ImageDataGenerator(rescale=1./255)
#
train_generator = train_datagen.flow_from_directory(train_dir,
                                                    batch_size=32,
                                                    class_mode='binary',
                                                    target_size=(150, 150))     
# --------------------
# Flow validation images in batches of 20 using test_datagen generator
# --------------------
validation_generator =  validation_datagen.flow_from_directory(validation_dir,
                                                         batch_size=32,
                                                         class_mode  = 'binary',
                                                         target_size = (150, 150))

# Use Adam Optmizer 
model.compile(optimizer='adam',
             loss='binary_crossentropy',
             metrics=['accuracy'])
Found 20000 images belonging to 2 classes.
Found 5000 images belonging to 2 classes.

Perform Gradient Descent

history=model.fit(train_generator,
                 validation_data=validation_generator,
                 steps_per_epoch=100,
                 epochs=15,
                 validation_steps=50,
                 verbose=2)
Epoch 1/15
100/100 - 27s - loss: 0.5716 - accuracy: 0.6922 - val_loss: 0.4843 - val_accuracy: 0.7744
Epoch 2/15
100/100 - 27s - loss: 0.5575 - accuracy: 0.7084 - val_loss: 0.4683 - val_accuracy: 0.7750
Epoch 3/15
100/100 - 26s - loss: 0.5452 - accuracy: 0.7228 - val_loss: 0.4856 - val_accuracy: 0.7665
Epoch 4/15
100/100 - 27s - loss: 0.5294 - accuracy: 0.7347 - val_loss: 0.4654 - val_accuracy: 0.7812
Epoch 5/15
100/100 - 27s - loss: 0.5352 - accuracy: 0.7350 - val_loss: 0.4557 - val_accuracy: 0.7981
Epoch 6/15
100/100 - 26s - loss: 0.5136 - accuracy: 0.7453 - val_loss: 0.4964 - val_accuracy: 0.7621
Epoch 7/15
100/100 - 27s - loss: 0.5249 - accuracy: 0.7334 - val_loss: 0.4959 - val_accuracy: 0.7556
Epoch 8/15
100/100 - 26s - loss: 0.5035 - accuracy: 0.7497 - val_loss: 0.4555 - val_accuracy: 0.7969
Epoch 9/15
100/100 - 26s - loss: 0.5024 - accuracy: 0.7487 - val_loss: 0.4675 - val_accuracy: 0.7728
Epoch 10/15
100/100 - 27s - loss: 0.5015 - accuracy: 0.7500 - val_loss: 0.4276 - val_accuracy: 0.8075
Epoch 11/15
100/100 - 26s - loss: 0.5002 - accuracy: 0.7581 - val_loss: 0.4193 - val_accuracy: 0.8131
Epoch 12/15
100/100 - 27s - loss: 0.4733 - accuracy: 0.7706 - val_loss: 0.5209 - val_accuracy: 0.7398
Epoch 13/15
100/100 - 27s - loss: 0.4999 - accuracy: 0.7538 - val_loss: 0.4109 - val_accuracy: 0.8075
Epoch 14/15
100/100 - 27s - loss: 0.4550 - accuracy: 0.7859 - val_loss: 0.3770 - val_accuracy: 0.8288
Epoch 15/15
100/100 - 26s - loss: 0.4688 - accuracy: 0.7688 - val_loss: 0.4764 - val_accuracy: 0.7786

Plot results

  • Plot training and validation accuracy
  • Plot training and validation loss
In [15]:
import matplotlib.pyplot as plt
#-----------------------------------------------------------
# Retrieve a list of list results on training and test data
# sets for each training epoch
#-----------------------------------------------------------
acc      = history.history[     'accuracy' ]
val_acc  = history.history[ 'val_accuracy' ]
loss     = history.history[    'loss' ]
val_loss = history.history['val_loss' ]

epochs   = range(len(acc)) # Get number of epochs

#------------------------------------------------
# Plot training and validation accuracy per epoch
#------------------------------------------------
plt.plot  ( epochs,     acc,label="training accuracy" )
plt.plot  ( epochs, val_acc, label='validation acuracy' )
plt.title ('Training and validation accuracy')
plt.legend()

plt.figure()

#------------------------------------------------
# Plot training and validation loss per epoch
#------------------------------------------------
plt.plot  ( epochs,     loss , label="training loss")
plt.plot  ( epochs, val_loss,label="validation loss" )
plt.title ('Training and validation loss'   )
plt.legend()
 


Implementation using Inception Network V3

The implementation is in the Colab notebook Cats_vs_Dog_3.ipynb

This is implemented as below

Use Inception V3

import os

from tensorflow.keras import layers
from tensorflow.keras import Model

  
from tensorflow.keras.applications.inception_v3 import InceptionV3
pre_trained_model = InceptionV3(input_shape = (150, 150, 3), 
                                include_top = False, 
                                weights = 'imagenet')


for layer in pre_trained_model.layers:
  layer.trainable = False
  
# pre_trained_model.summary()

last_layer = pre_trained_model.get_layer('mixed7')
print('last layer output shape: ', last_layer.output_shape)
last_output = last_layer.output
Downloading data from https://storage.googleapis.com/tensorflow/keras-applications/inception_v3/inception_v3_weights_tf_dim_ordering_tf_kernels_notop.h5
87916544/87910968 [==============================] - 1s 0us/step
last layer output shape:  (None, 7, 7, 768)

Use Layer 7 of Inception Network

  • Use Image Augumentation
  • Use Adam Optimizer
In [0]:
import tensorflow as tf
from tensorflow import keras
from tensorflow.keras.optimizers import RMSprop
from tensorflow.keras.preprocessing.image import ImageDataGenerator
# Flatten the output layer to 1 dimension
x = layers.Flatten()(last_output)
# Add a fully connected layer with 1,024 hidden units and ReLU activation
x = layers.Dense(1024, activation='relu')(x)
# Add a dropout rate of 0.2
x = layers.Dropout(0.2)(x)                  
# Add a final sigmoid layer for classification
x = layers.Dense  (1, activation='sigmoid')(x)           

model = Model( pre_trained_model.input, x) 
#train_datagen = ImageDataGenerator( rescale = 1.0/255. )
#validation_datagen = ImageDataGenerator( rescale = 1.0/255. )

train_datagen = ImageDataGenerator(
      rescale=1./255,
      #rotation_range=90,
      width_shift_range=0.2,
      height_shift_range=0.2,
      shear_range=0.2,
      zoom_range=0.2)
      #horizontal_flip=True,
      #fill_mode='nearest')

validation_datagen = ImageDataGenerator(rescale=1./255)
#
train_generator = train_datagen.flow_from_directory(train_dir,
                                                    batch_size=32,
                                                    class_mode='binary',
                                                    target_size=(150, 150))     
# --------------------
# Flow validation images in batches of 20 using test_datagen generator
# --------------------
validation_generator =  validation_datagen.flow_from_directory(validation_dir,
                                                         batch_size=32,
                                                         class_mode  = 'binary',
                                                         target_size = (150, 150))


model.compile(optimizer='adam',
             loss='binary_crossentropy',
             metrics=['accuracy'])
Found 20000 images belonging to 2 classes.
Found 5000 images belonging to 2 classes.

Fit model

history=model.fit(train_generator,
                 validation_data=validation_generator,
                 steps_per_epoch=100,
                 epochs=15,
                 validation_steps=50,
                 verbose=2)
Epoch 1/15
100/100 - 31s - loss: 0.5961 - accuracy: 0.8909 - val_loss: 0.1919 - val_accuracy: 0.9456
Epoch 2/15
100/100 - 30s - loss: 0.2002 - accuracy: 0.9259 - val_loss: 0.1025 - val_accuracy: 0.9550
Epoch 3/15
100/100 - 30s - loss: 0.1618 - accuracy: 0.9366 - val_loss: 0.0920 - val_accuracy: 0.9581
Epoch 4/15
100/100 - 29s - loss: 0.1442 - accuracy: 0.9381 - val_loss: 0.0960 - val_accuracy: 0.9600
Epoch 5/15
100/100 - 30s - loss: 0.1402 - accuracy: 0.9381 - val_loss: 0.0703 - val_accuracy: 0.9794
Epoch 6/15
100/100 - 30s - loss: 0.1437 - accuracy: 0.9413 - val_loss: 0.1090 - val_accuracy: 0.9531
Epoch 7/15
100/100 - 30s - loss: 0.1325 - accuracy: 0.9428 - val_loss: 0.0756 - val_accuracy: 0.9670
Epoch 8/15
100/100 - 29s - loss: 0.1341 - accuracy: 0.9491 - val_loss: 0.0625 - val_accuracy: 0.9737
Epoch 9/15
100/100 - 29s - loss: 0.1186 - accuracy: 0.9513 - val_loss: 0.0934 - val_accuracy: 0.9581
Epoch 10/15
100/100 - 29s - loss: 0.1171 - accuracy: 0.9513 - val_loss: 0.0642 - val_accuracy: 0.9727
Epoch 11/15
100/100 - 29s - loss: 0.1018 - accuracy: 0.9591 - val_loss: 0.0930 - val_accuracy: 0.9606
Epoch 12/15
100/100 - 29s - loss: 0.1190 - accuracy: 0.9541 - val_loss: 0.0737 - val_accuracy: 0.9719
Epoch 13/15
100/100 - 29s - loss: 0.1223 - accuracy: 0.9494 - val_loss: 0.0740 - val_accuracy: 0.9695
Epoch 14/15
100/100 - 29s - loss: 0.1158 - accuracy: 0.9516 - val_loss: 0.0659 - val_accuracy: 0.9744
Epoch 15/15
100/100 - 29s - loss: 0.1168 - accuracy: 0.9591 - val_loss: 0.0788 - val_accuracy: 0.9669

Plot results

  • Plot training and validation accuracy
  • Plot training and validation loss
In [14]:
import matplotlib.pyplot as plt
#-----------------------------------------------------------
# Retrieve a list of list results on training and test data
# sets for each training epoch
#-----------------------------------------------------------
acc      = history.history[     'accuracy' ]
val_acc  = history.history[ 'val_accuracy' ]
loss     = history.history[    'loss' ]
val_loss = history.history['val_loss' ]

epochs   = range(len(acc)) # Get number of epochs

#------------------------------------------------
# Plot training and validation accuracy per epoch
#------------------------------------------------
plt.plot  ( epochs,     acc,label="training accuracy" )
plt.plot  ( epochs, val_acc, label='validation acuracy' )
plt.title ('Training and validation accuracy')
plt.legend()

plt.figure()

#------------------------------------------------
# Plot training and validation loss per epoch
#------------------------------------------------
plt.plot  ( epochs,     loss , label="training loss")
plt.plot  ( epochs, val_loss,label="validation loss" )
plt.title ('Training and validation loss'   )
plt.legend()

 

I intend to do some interesting stuff with Convolutional Neural Networks.

Watch this space!

See also
1. Architecting a cloud based IP Multimedia System (IMS)
2. Exploring Quantum Gate operations with QCSimulator
3. Big Data 6: The T20 Dance of Apache NiFi and yorkpy
4. The Many Faces of Latency
5. The Clash of the Titans in Test and ODI cricket

To see all posts click Index of posts

Big Data 6: The T20 Dance of Apache NiFi and yorkpy

“I don’t count my sit-ups. I only start counting once it starts hurting. ”

Muhammad Ali

“Hard work beats talent when talent doesn’t work hard.”

Tim Notke

In my previous post Big Data 5: kNiFI-ing through cricket data with Apache NiFi and yorkpy, I created a Big Data Pipeline that takes raw data in YAML format from a Cricsheet to processing and ranking IPL T20 players. In that post I had mentioned that we could create a similar pipeline to create a real time dashboard of IPL Analytics. I could have have done this but I needed to know how to create a Web UI. After digging and poking around, I have been able to create a simple Web UI running off Apache Web server. This UI uses basic JQuery and CSS to display a real time IPL T20 dashboard. As in my previous post, this is an end-2-end Big Data pipeline which can handle large data sets at scheduled times, process them and generate real time dashboards.

We could imagine an inter-galactic T20 championship league where T20 data comes in every hour or sooner and we need to perform analytics to see if us earthlings are any better than people with pointy heads  or little green men. The NiFi pipeline could be used as-is, however the yorkpy package would have to be rewritten in Pyspark. That is in another eon, though.

My package yorkpy has around ~45+ functions which fall in the following main categories

1. Pitching yorkpy . short of good length to IPL – Part 1 :Class 1: This includes functions that convert the yaml data of IPL matches into Pandas dataframe which are then saved as CSV. This part can perform analysis of individual IPL matches.
2. Pitching yorkpy.on the middle and outside off-stump to IPL – Part 2 :Class 2:This part includes functions to create a large data frame for head-to-head confrontation between any 2IPL teams says CSK-MI, DD-KKR etc, which can be saved as CSV. Analysis is then performed on these team-2-team confrontations.
3. Pitching yorkpy.swinging away from the leg stump to IPL – Part 3 Class 3:The 3rd part includes the performance of any IPL team against all other IPL teams. The data can also be saved as CSV.
4. Pitching yorkpy … in the block hole – Part 4 :Class 4: This part performs analysis of individual IPL batsmen and bowlers

 

Watch the live demo of the end-2-end NiFi pipeline at ‘The T20 Dance

You can download the NiFi template and associated code from Github at  T20 Dance

The Apache NiFi Pipeline is shown below

1. T20 Dance – Overall NiFi Pipeline

 

There are 5 process groups

2. ListAndConvertYaml2DataFrames

This post starts with having the YAML files downloaded and unpacked from Cricsheet.  The individual YAML files are converted into Pandas dataframes and saved as CSV. A concurrency of 12 is used to increase performance and process YAML files in parallel. The processor MergeContent creates a merged content to signal the completion of conversion and triggers the other Process Groups through a funnel.

 

3. Analyse individual IPL T20 matches

This Process Group ‘Analyse T20 matches’  used the yorkpy’s Class 1 functions which can perform analysis of individual IPL T20 matches. The matchWorm() and matchScorecard() functions are used, through any other function could have been used. The Process Group is shown below

 

4. Analyse performance of an IPL team in all matches against another IPL team

This Process Group ‘Analyse performance of IPL team in all matched against another IPL team‘ does analysis in all matches between any 2 IPL teams (Class 2) as shown below

5. Analyse performance of IPL team in all matches against all other IPL teams

This uses Class 3 functions. Individual data sets for each IPL team versus all other IPL teams is created before Class 3 yorkpy functions are invoked. This is included below

6. Analyse performances of IPL batsmen and bowlers

This Process Group uses Class 4 yorkpy functions. The match CSV files are processed to get batting and bowling details before calling the individual functions as shown below

 

7. IPL T20 Dashboard

The IPL T20 Dashboard is shown

 

Conclusion

This NiFI pipeline was done for IPL T20 however, it could be done for any T20 format like Intl T20, BBL, Natwest etc which are posted in Cricsheet. Also, only a subset of the yorkpy functions were used. There is a much wider variety of functions available.

Hope the T20 dance got your foot a-tapping!

 

You may also like
1. A primer on Qubits, Quantum gates and Quantum Operations
2.Computer Vision: Ramblings on derivatives, histograms and contours
3.Deep Learning from first principles in Python, R and Octave – Part 6
4.A Bluemix recipe with MongoDB and Node.js
5.Practical Machine Learning with R and Python – Part 4
6.Simulating the domino effect in Android using Box2D and AndEngine

To see all posts click Index of posts

Big Data-5: kNiFi-ing through cricket data with yorkpy

“The temptation to form premature theories upon insufficient data is the bane of our profession.”

                              Sherlock Holmes in the Valley of fear by Arthur Conan Doyle

“If we have data, let’s look at data. If all we have are opinions, let’s go with mine.”

                              Jim Barksdale, former CEO Netscape 

In this post I use  Apache NiFi Dataflow Pipeline along with my Python package yorkpy to crunch through cricket data from Cricsheet. The Data Pipelne  flows all the way from the source  to target analytics output. Apache NiFi was created to automate the flow of data between systems.  NiFi dataflows enable the automated and managed flow of information between systems. This post automates the flow of data from Cricsheet, from where the zip file it is downloaded, unpacked, processed, transformed and finally T20 players are ranked.

While this is a straight forward example of what can be done, this pattern can be applied to real Big Data systems. For example hypothetically, we could consider that we get several parallel streams of  cricket data or for that matter any sports related data. There could be parallel Data flow pipelines that get the data from the sources. This would then be  followed by data transformation modules and finally a module for generating analytics. At the other end a UI based on AngularJS or ReactJS could display the results in a cool and awesome way.

Incidentally, the NiFi pipeline that I discuss in this post, is a simplistic example, and does not use the Big Data stack like HDFS, Hive, Spark etc. Nevertheless, the pattern used, has all the modules for a Big Data pipeline namely ingestion, unpacking, transformation and finally analytics. This NiF pipeline demonstrates the flow using the regular file system of Mac and my python based package yorkpy. The concepts mentioned could be used in a real Big Data scenario which has much fatter pipes of data coming. If  this was the case the NiFi pipeline would utilize  HDFS/Hive for storing the ingested data and Pyspark/Scala for the transformation and analytics and other related technologies.

A pictorial representation is given below

In the diagram above each of the vertical boxes could be any technology from the ever proliferating Big Data stack namely HDFS, Hive, Spark, Sqoop, Kafka, Impala and so on.  Such a dataflow automation could be created when any big sporting event happens, as long as the data generated large, and there is a need for dynamic and automated reporting. The UI could be based on AngularJS/ReactJS and could display analytical tables and charts.

This post demonstrates one such scenario in which IPL T20 data is downloaded from Cricsheet site, unpacked and stored in a specific directory. This dataflow automation is based on my yorkpy package. To know more about the yorkpy package  see Pitching yorkpy … short of good length to IPL – Part 1  and the associated parts. The zip file, from Cricsheet, contains individual IPL T20 matches in YAML format. The convertYaml2DataframeT20() function is used to convert the YAML files into Pandas dataframes before storing them as CSV files. After this done, the function rankIPLT20batting() function is used to perform the overall ranking of the T20 players. My yorkpy Python package has about ~ 50+ functions that perform various analytics on any T20 data for e.g it has the following classes of functions

  • analyze T20 matches
  • analyze performance of a T20 team in all matches against another T20 team
  • analyze performance of a T20 team against all other T20 teams
  • analyze performance of T20 batsman and bowlers
  • rank T20 batsmen and bowlers

The functions of yorkpy generate tables or charts. While this post demonstrates one scenario, we could use any of the yorkpy T20 functions, generate the output and display on a widget in the UI display, created with cool technologies like AngularJS/ReactJS,  possibly in near real time as data keeps coming in.,

To use yorkpy with NiFI the following packages have to be installed in your environment

-pip install yorkpy
-pip install pyyaml
-pip install pandas
-yum install python-devel (equivalent in Windows)
-pip install matplotlib
-pip install seaborn
-pip install sklearn
-pip install datetime

I have created a video of the NiFi Pipeline with the real dataflow fro source to the ranked IPL T20 batsmen. Take a look at RankingT20PlayersWithNiFiYorkpy

You can clone/fork the NiFi template from rankT20withNiFiYorkpy

The NiFi Data Flow Automation is shown below

1. Overall flow

The overall NiFi flow contains 2 Process Groups a) DownloadAnd Unpack. b) Convert and Rank IPL batsmen. While it appears that the Process Groups are disconnected, they are not. The first process group downloads the T20 zip file, unpacks the. zip file and saves the YAML files in a specific folder. The second process group monitors this folder and starts processing as soon the YAML files are available. It processes the YAML converting it into dataframes before storing it as CSV file. The next  processor then does the actual ranking of the batsmen before writing the output into IPLrank.txt

1.1 DownloadAndUnpack Process Group

This process group is shown below

1.1.1 GetT20Data

The GetT20Data Processor downloads the zip file given the URL

The ${T20data} variable points to the specific T20 format that needs to be downloaded. I have set this to https://cricsheet.org/downloads/ipl.zip. This could be set any other data set. In fact we could have parallel data flows for different T20/ Sports data sets and generate

1.1.2 SaveUnpackedData

This processor stores the YAML files in a predetermined folder, so that the data can be picked up  by the 2nd Process Group for processing

1.2 ProcessAndRankT20Players Process Group

This is the second process group which converts the YAML files to pandas dataframes before storing them as. CSV files. The RankIPLPlayers will then read all the CSV files, stack them and then proceed to rank the IPL players. The Process Group is shown below

1.2.1 ListFile and FetchFile Processors

The left 2 Processors ListFile and FetchFile get all the YAML files from the folder and pass it to the next processor

1.2.2 convertYaml2DataFrame Processor

The convertYaml2DataFrame Processor uses the ExecuteStreamCommand which call a python script. The Python script invoked the yorkpy function convertYaml2Dataframe() as shown below

The ${convertYaml2Dataframe} variable points to the python file below which invoked the yorkpy function yka.convertYaml2PandasDataframeT20()

import yorkpy.analytics as yka
import argparse
parser = argparse.ArgumentParser(description='convert')
parser.add_argument("yamlFile",help="YAML File")
args=parser.parse_args()
yamlFile=args.yamlFile
yka.convertYaml2PandasDataframeT20(yamlFile,"/Users/tvganesh/backup/software/nifi/ipl","/Users/tvganesh/backup/software/nifi/ipldata")

This function takes as input $filename which comes from FetchFile processor which is a FlowFile. So I have added a concurrency of 8  to handle upto 8 Flowfiles at a time. The thumb rule as I read on the internet is 2x, 4x the number of cores of your system. Since I have an 8 core Mac, I could possibly have gone ~ 30 concurrent threads. Also the number of concurrent threads is less when the flow is run in a Oracle Box VirtualMachine. Box since a vCore < actual Core

The scheduling tab is as below

Here are the 8 concurrent Python threads on Mac at bottom right… (pretty cool!)

I have not fully tested how latency vs throughput slider changes, affects the performance.

1.2.3 MergeContent Processor

This processor’s only job is to trigger the rankIPLPlayers when all the FlowFiles have merged into 1 file.

1.2.4 RankT20Players

This processor is an ExecuteStreamCommand Processor that executes a Python script which invokes a yorkpy function rankIPLT20Batting()

import yorkpy.analytics as yka
rank=yka.rankIPLT20Batting("/Users/tvganesh/backup/software/nifi/ipldata")
print(rank.head(15))

1.2.5 OutputRankofT20Player Processor

This processor writes the generated rank to an output file.

1.3 Final Ranking of IPL T20 players

The Nodejs based web server picks up this file and displays on the web page the final ranks (the code is based on a good youtube for reading from file)

2. Final thoughts

As I have mentioned above though the above NiFi Cricket Dataflow automation does not use the Hadoop ecosystem, the pattern used is valid and can be used with some customization in Big Data flows as parallel stream. I could have also done this on Oracle VirtualBox but I thought since the code is based on Python and Pandas there is no real advantage of running on the VirtualBox.  GIve the NiFi flow a shot. Have fun!!!

Also see
1.My book ‘Deep Learning from first Practical Machine Learning with R and Python – Part 5
Edition’ now on Amazon

2. Introducing QCSimulator: A 5-qubit quantum computing simulator in R
3.De-blurring revisited with Wiener filter using OpenCV
4. Practical Machine Learning with R and Python – Part 5
5. Natural language processing: What would Shakespeare say?
6.Getting started with Tensorflow, Keras in Python and R
7.Revisiting World Bank data analysis with WDI and gVisMotionChart

To see all posts click Index of posts

Ranking T20 players in Intl T20, IPL, BBL and Natwest using yorkpy

There is a voice that doesn’t use words, listen.
When someone beats a rug, the blows are not against the rug, but against the dust in it.
I lost my hat while gazing at the moon, and then I lost my mind.
Rumi

Introduction

After a long hiatus, I am back to my big, bad, blogging ways! In this post I rank T20 players from several different leagues namely

  • International T20
  • Indian Premier League (IPL) T20
  • Big Bash League (BBL) T20
  • Natwest Blast (NTB) T20

I have added 8 new functions to my Python Package yorkpy, which will perform the ranking for the above 4 T20 League formats. To know more about my Python package see Pitching yorkpy . short of good length to IPL – Part 1, and the related posts on yorkpy. The code can be easily extended to other leagues which have a the same ‘yaml’ format for the matches. I also fixed some issues which started to crop up, possibly because a few things have changed in the new data.

The new functions are

  1. rankIntlT20Batting()
  2. rankIntlT20Batting()
  3. rankIPLT20Batting()
  4. rankIPLT20Batting
  5. rankBBLT20Batting()
  6. rankBBLT20Batting()
  7. rankNTBT20Batting()
  8. rankNTBT20Batting()

The yorkpy package uses data from Cricsheet

You can clone/fork the code for yorkpy at yorkpy

You can download the PDF of the post from Rank T20

yorkpy can be installed with ‘pip install yorkpy

1. International T20

The steps to do before ranking for International T20 matches are 1. Download International T20 zip file from Cricsheet Intl T20 2. Unzip the file. This will create a folder with yaml files

import yorkpy.analytics as yka
#yka.convertAllYaml2PandasDataframesT20("../t20s","../data")

This above step will convert the yaml files into CSV files. Now do the ranking as below

1a. Ranking of International T20 batsmen

import yorkpy.analytics as yka
intlT20RankBatting=yka.rankIntlT20Batting("C:\\software\\cricket-package\\yorkpyPkg\\data\\data")
intlT20RankBatting.head(15)
##                      matches  runs_mean     SR_mean
## batsman                                            
## V Kohli                   58  38.672414  125.212402
## KS Williamson             42  32.595238  122.884631
## Mohammad Shahzad          52  31.942308  118.212288
## CH Gayle                  50  31.140000  111.869984
## BB McCullum               69  29.492754  117.011666
## MM Lanning                48  28.812500   98.582663
## SJ Taylor                 44  28.659091   98.684856
## MJ Guptill                68  28.573529  117.673702
## DA Warner                 71  28.507042  121.142746
## DPMD Jayawardene          53  27.584906  107.787092
## KC Sangakkara             54  26.407407  106.039838
## JP Duminy                 68  26.294118  114.606717
## TM Dilshan                78  26.243590   97.910384
## RG Sharma                 65  25.907692  113.056548
## H Masakadza               53  25.566038   99.453880

1b. Ranking of International T20 bowlers

import yorkpy.analytics as yka
intlT20RankBowling=yka.rankIntlT20Bowling("C:\\software\\cricket-package\\yorkpyPkg\\data\\data")
intlT20RankBowling.head(15)
##                       matches  wicket_mean  econrate_mean
## bowler                                                   
## Umar Gul                   58     1.603448       7.637931
## SL Malinga                 78     1.500000       7.409188
## Saeed Ajmal                63     1.492063       6.451058
## DW Steyn                   46     1.478261       7.014855
## A Shrubsole                45     1.422222       6.294444
## M Morkel                   41     1.292683       7.680894
## KMDN Kulasekara            57     1.280702       7.476608
## TG Southee                 51     1.274510       8.759804
## SCJ Broad                  53     1.264151            inf
## Shakib Al Hasan            58     1.241379       6.836207
## R Ashwin                   44     1.204545       7.162879
## Nida Dar                   44     1.204545       6.083333
## KH Brunt                   44     1.204545       5.982955
## KD Mills                   42     1.166667       8.289683
## SR Watson                  46     1.152174       8.246377

2. Indian Premier League (IPL) T20

The steps to do before ranking for IPL T20 matches are 1. Download IPL T20 zip file from Cricsheet IPL T20 2. Unzip the file. This will create a folder with yaml files

import yorkpy.analytics as yka
#yka.convertAllYaml2PandasDataframesT20("../ipl","../ipldata")

This above step will convert the yaml files into CSV files in the /ipldata folder. Now do the ranking as below

2a. Ranking of batsmen in IPL T20

import yorkpy.analytics as yka
IPLT20RankBatting=yka.rankIPLT20Batting("C:\\software\\cricket-package\\yorkpyPkg\\data\\ipldata")
IPLT20RankBatting.head(15)
##                    matches  runs_mean     SR_mean
## batsman                                          
## DA Warner              129  37.589147  119.917864
## CH Gayle               123  36.723577  125.256818
## SE Marsh                70  36.314286  114.707578
## KL Rahul                59  33.542373  123.424971
## MEK Hussey              60  33.400000  100.439187
## V Kohli                174  32.413793  115.830849
## KS Williamson           42  31.690476  120.443172
## AB de Villiers         143  30.923077  128.967081
## JC Buttler              45  30.800000  132.561154
## AM Rahane              118  30.330508  102.240398
## SR Tendulkar            79  29.949367  101.651959
## F du Plessis            65  29.415385  112.462114
## Q de Kock               51  29.333333  110.973836
## SS Iyer                 47  29.170213  102.144222
## G Gambhir              155  28.741935  103.997558

2b. Ranking of bowlers in IPL T20

import yorkpy.analytics as yka
IPLT20RankBowling=yka.rankIPLT20Bowling("C:\\software\\cricket-package\\yorkpyPkg\\data\\ipldata")
IPLT20RankBowling.head(15)
##                      matches  wicket_mean  econrate_mean
## bowler                                                  
## SL Malinga               122     1.540984       7.173361
## Imran Tahir               43     1.465116       8.155039
## A Nehra                   88     1.375000       7.923295
## MJ McClenaghan            56     1.339286       8.638393
## Rashid Khan               46     1.304348       6.543478
## Sandeep Sharma            79     1.303797       7.860759
## MM Patel                  63     1.301587       7.530423
## DJ Bravo                 131     1.282443       8.458333
## M Morkel                  70     1.257143       7.760714
## SP Narine                109     1.256881       6.747706
## YS Chahal                 83     1.228916       8.103659
## R Vinay Kumar            104     1.221154       8.556090
## RP Singh                  82     1.219512       8.149390
## CH Morris                 52     1.211538       7.854167
## B Kumar                  117     1.205128       7.536325

3. Natwest T20

The steps to do before ranking for Natwest T20 matches are 1. Download Natwest T20 zip file from Cricsheet NTB T20 2. Unzip the file. This will create a folder with yaml files

import yorkpy.analytics as yka
#yka.convertAllYaml2PandasDataframesT20("../ntb","../ntbdata")

This above step will convert the yaml files into CSV files in the /ntbdata folder. Now do the ranking as below

3a. Ranking of NTB batsmen

import yorkpy.analytics as yka
NTBT20RankBatting=yka.rankNTBT20Batting("C:\\software\\cricket-package\\yorkpyPkg\\data\\ntbdata")
NTBT20RankBatting.head(15)
##                      matches  runs_mean     SR_mean
## batsman                                            
## Babar Azam                13  44.461538  121.268809
## T Banton                  13  42.230769  139.376274
## JJ Roy                    12  41.250000  142.182147
## DJM Short                 12  40.250000  131.182294
## AN Petersen               12  37.916667  132.522727
## IR Bell                   13  37.615385  130.104721
## M Klinger                 26  35.346154  112.682922
## EJG Morgan                16  35.062500  129.817650
## AJ Finch                  19  34.578947  137.093465
## MH Wessels                26  33.884615  116.300969
## S Steel                   11  33.545455  140.118207
## DJ Bell-Drummond          21  33.142857  108.566309
## Ashar Zaidi               11  33.000000  178.553331
## DJ Malan                  26  33.000000  120.127202
## T Kohler-Cadmore          23  32.956522  112.493019

3b. Ranking of NTB bowlers

import yorkpy.analytics as yka
NTBT20RankBowling=yka.rankNTBT20Bowling("C:\\software\\cricket-package\\yorkpyPkg\\data\\ntbdata")
NTBT20RankBowling.head(15)
##                        matches  wicket_mean  econrate_mean
## bowler                                                    
## MW Parkinson                11     2.000000       7.628788
## HF Gurney                   23     1.956522       8.831884
## GR Napier                   12     1.916667       8.694444
## R Rampaul                   19     1.736842       7.131579
## P Coughlin                  11     1.727273       8.909091
## AJ Tye                      26     1.692308       8.227564
## GC Viljoen                  12     1.666667       7.708333
## BAC Howell                  21     1.666667       6.857143
## BW Sanderson                12     1.583333       7.902778
## KJ Abbott                   14     1.571429       9.398810
## JE Taylor                   13     1.538462       9.839744
## JDS Neesham                 12     1.500000      10.812500
## MJ Potts                    12     1.500000       8.486111
## TT Bresnan                  21     1.476190       8.817460
## T van der Gugten            13     1.461538       7.211538

4. Big Bash Leagure (BBL) T20

The steps to do before ranking for BBL T20 matches are 1. Download BBL T20 zip file from Cricsheet BBL T20 2. Unzip the file. This will create a folder with yaml files

import yorkpy.analytics as yka
#yka.convertAllYaml2PandasDataframesT20("../bbl","../bbldata")

This above step will convert the yaml files into CSV files in the /bbldata folder. Now do the ranking as below

4a. Ranking of BBL batsmen

import yorkpy.analytics as yka
BBLT20RankBatting=yka.rankBBLT20Batting("C:\\software\\cricket-package\\yorkpyPkg\\data\\bbldata")
BBLT20RankBatting.head(15)
##                 matches  runs_mean     SR_mean
## batsman                                       
## DJM Short            43  40.883721  118.773047
## SE Marsh             47  39.148936  113.616053
## AJ Finch             62  36.306452  120.271231
## AT Carey             37  34.945946  120.125341
## UT Khawaja           41  31.268293  107.355655
## CA Lynn              74  31.162162  121.746578
## MS Wade              46  30.782609  120.310081
## TM Head              45  30.000000  126.769564
## MEK Hussey           23  29.173913  109.492934
## BJ Hodge             29  29.000000  124.438040
## BR Dunk              39  28.230769  106.149913
## AD Hales             31  27.161290  117.678008
## BB McCullum          34  27.058824  115.486392
## GJ Bailey            57  27.000000  121.159220
## MR Marsh             47  26.510638  114.994909

4b. Ranking of BBL bowlers

import yorkpy.analytics as yka
BBLT20RankBowling=yka.rankBBLT20Bowling("C:\\software\\cricket-package\\yorkpyPkg\\data\\bbldata")
BBLT20RankBowling.head(15)
##                    matches  wicket_mean  econrate_mean
## bowler                                                
## Yasir Arafat            15     2.000000       7.587778
## CH Morris               15     1.733333       8.572222
## TK Curran               27     1.629630       8.716049
## TT Bresnan              13     1.615385       8.775641
## JR Hazlewood            18     1.555556       7.361111
## CJ McKay                15     1.533333       8.555556
## DR Sams                 36     1.527778       8.581019
## AC McDermott            14     1.500000       9.166667
## JP Faulkner             20     1.500000       8.345833
## SP Narine               12     1.500000       7.395833
## AJ Tye                  51     1.490196       8.101307
## M Kelly                 21     1.476190       8.908730
## SA Abbott               73     1.438356       8.737443
## B Laughlin              82     1.426829       8.332317
## SW Tait                 31     1.419355       8.895161

Conclusion

You should be able to now rank players in the above formats as new data is added to Cricsheet. yorkpy can also be used for other leagues which follow the Cricsheet format.

Also see
1. Deep Learning from first principles in Python, R and Octave – Part 5
2. Using Linear Programming (LP) for optimizing bowling change or batting lineup in T20 cricket
3. Using Reinforcement Learning to solve Gridworld
4. Big Data-4: Webserver log analysis with RDDs, Pyspark, SparkR and SparklyR
5. My book ‘Practical Machine Learning in R and Python: Third edition’ on Amazon
6. Deblurring with OpenCV: Weiner filter reloaded
7. Rock N’ Roll with Bluemix, Cloudant & NodeExpress
8. Modeling a Car in Android

To see all posts click Index of posts

Using Reinforcement Learning to solve Gridworld

“Take up one idea. Make that one idea your life — think of it, dream of it, live on that idea. Let the brain, muscles, nerves, every part of your body, be full of that idea, and just leave every other idea alone. This is the way to success.”

– Swami Vivekananda

“Be the change you want to see in the world”

– Mahatma Gandhi

“If you want to shine like the sun, first burn like the sun”

-Shri A.P.J Abdul Kalam

 

Reinforcement Learning

Reinforcement Learning (RL) involves decision making under uncertainty which tries to maximize return over successive states.There are four main elements of a Reinforcement Learning system: a policy, a reward signal, a value function. The policy is a mapping from the states to actions or a probability distribution of actions. Every action the agent takes results in a numerical reward. The agent’s sole purpose is to maximize the reward in the long run.

Reinforcement Learning is very different from Supervised, Unsupervised and Semi-supervised learning where the data is either labeled, unlabeled or partially labeled and the learning algorithm tries to learn the target values from the input features which is then used either for inference or prediction. In unsupervised the intention is to extract patterns from the data. In Reinforcement Learning the agent/robot takes action in each state based on the reward it would get for a particular action in a specific state with the goal of maximizing the reward. In many ways Reinforcement Learning is similar to how human beings and animals learn. Every action we take is with the goal of increasing our overall happiness, contentment, money,fame, power over the opposite!

RL has been used very effectively in many situations, the most famous is AlphaGo from Deep Mind, the first computer program to defeat a professional Go player in the Go game, which is supposed to be extremely complex. Also AlphaZero, from DeepMind has a higher ELO rating than that of Stockfish and was able to beat Stockfish 800+ times in 1000 chess matches. Take a look at DeepMind

In this post, I use some of the basic concepts of Reinforcment Learning to solve Grids (mazes). With this we can solve mazes, with arbitrary size, shape and complexity fairly easily. The RL algorithm can find the optimal path through the maze. Incidentally, I recollect recursive algorithms in Data Structures book which take a much more complex route with a lot of back tracking to solve maze problems

Reinforcement Learning involves decision making under uncertainty which tries to maximize return over successive states.There are four main elements of a Reinforcement Learning system: a policy, a reward signal, a value function. The policy is a mapping from the states to actions or a probability distribution of actions. Every action the agent takes results in a numerical reward. The agent’s sole purpose is to maximize the reward in the long run.

The reward indicates the immediate return, a value function specifies the return in the long run. Value of a state is the expected reward that an agent can accrue.

The agent/robot takes an action in At in state St and moves to state S’t anf gets a reward Rt+1 as shown

An agent will seek to maximize the overall return as it transition across states
The expected return can be expressed as
G_{t} = R_{t+1} + \gamma G_{t+1} where G_{t} is the expected return in time t and the discounted expected return G_{t+1} in time t+1

A policy is a mapping from states to probabilities of selecting each possible action. If the agent is following policy \pi at time t, then \pi(a|s) is the probability that A_{t} = a if S_{t} = s.

The value function of a state s under a policy \pi, denoted v_{\pi}(s), is the expected return when starting in s and following \pi thereafter

This can be written as

v_{\pi}(s) = E_{\pi}[G_{t} |S_{t}=s] = E_{\pi}[\sum_{k=0}^{k=Inf} \gamma^{k}R_{t+k+1}|S_{t}=s]

= E_{\pi}[R_{t+1} + \gamma G_{t+1} |S_{t}=s]

v_{\pi}(s)=\sum_{a} \pi(a|s) \sum_{s',r} p(s',r|s,a)[r+\gamma*v_{\pi}(s')]

Similarly the action value function gives the expected return when taking an action ‘a’ in state ‘s’
q_{\pi}(s,a)= \sum_{s',r} p(s',r|s,a)[r+\gamma*\pi(a|s)q_{\pi}(s',a')]

These are Bellman’s equation for the state value function

The Bellman equations give the equation for each of the state

The Bellman optimality equations give the optimal policy of choosing specific actions in specific states to achieve the maximum reward and reach the goal efficiently. They are given as

v_{*}(s)=max_{a}\sum_{s',r} p(s',r|s,a)[r+\gamma*v_{*}(s')]

q_{*}(s,a)=\sum_{s',r} p(s',r|s,a)[r+\gamma*max_{a}q_{*}(s',a')]

The Bellman equations cannot be used directly in goal directed problems and dynamic programming is used instead where the value functions are computed iteratively

n this post I solve Grids using Reinforcement Learning. In the problem below the Maze has 2 end states as shown in the corner. There are four possible actions in each state up, down, right and left. If an action in a state takes it out of the grid then the agent remains in the same state. All actions have a reward of -1 while the end states have a reward of 0

This is shown as

where the reward for any transition is Rt=1Rt=−1 except the transition to the end states at the corner which have a reward of 0. The policy is a uniform policy with all actions being equi-probable with a probability of 1/4 or 0.25

You can fork/clone the code from my Github repository – Gridworld
Note: This post shows 3 different grids each with slightly more complexity and uses 3 methods
a) Bellman Update
b) Greedification
c) Bellman Optimality Update
with dynamic programming to solve the Grids

1. Gridworld-1

In [1]:
import numpy as np
import random
In [2]:
gamma = 1 # discounting rate
gridSize = 4
rewardValue = -1
terminationStates = [[0,0], [gridSize-1, gridSize-1]]
actions = [[-1, 0], [1, 0], [0, 1], [0, -1]]
numIterations = 1000

The action value provides the next state for a given action in a state and the accrued reward

In [3]:
def actionValue(initialPosition,action):
    if initialPosition in terminationStates:
        finalPosition = initialPosition
        reward=0
    else:
        #Compute final position
        finalPosition = np.array(initialPosition) + np.array(action)
        reward= rewardValue
    # If the action moves the finalPosition out of the grid, stay in same cell
    if -1 in finalPosition or gridSize in finalPosition:
        finalPosition = initialPosition
        reward= rewardValue
    
    #print(finalPosition)
    return finalPosition, reward

1a. Bellman Update

In [4]:
# Initialize valueMap and valueMap1
valueMap = np.zeros((gridSize, gridSize))
valueMap1 = np.zeros((gridSize, gridSize))
states = [[i, j] for i in range(gridSize) for j in range(gridSize)]
In [5]:
def policy_evaluation(numIterations,gamma,theta,valueMap):
    for i in range(numIterations):
        delta=0
        for state in states:
            weightedRewards=0
            for action in actions:
                finalPosition,reward = actionValue(state,action)
                weightedRewards += 1/4* (reward + gamma * valueMap[finalPosition[0],finalPosition][1])
            valueMap1[state[0],state[1]]=weightedRewards
            delta =max(delta,abs(weightedRewards-valueMap[state[0],state[1]]))
        valueMap = np.copy(valueMap1)
        if(delta < 0.01):                                                
            print(valueMap)
            break
In [6]:
valueMap = np.zeros((gridSize, gridSize))
valueMap1 = np.zeros((gridSize, gridSize))
states = [[i, j] for i in range(gridSize) for j in range(gridSize)]
policy_evaluation(1000,1,0.001,valueMap)
[[  0.         -13.89528403 -19.84482978 -21.82635535]
 [-13.89528403 -17.86330422 -19.84586777 -19.84482978]
 [-19.84482978 -19.84586777 -17.86330422 -13.89528403]
 [-21.82635535 -19.84482978 -13.89528403   0.        ]]

Findings

The valueMap is the result of several sweeps through all the states. It can be seen that the cells in the corner state have a higher value. We can start on any cell in the grid and move in the direction which is greater than the current state and we will reach the end state

1b. Greedify

The previous alogirthm while it works is somewhat inefficient as we have to sweep over the states to compute the state value function. The approach below works on the same problem but after each computation of the value function, a greedifications takes place to ensure that the action with the highest return is selected after which the policy ππ is followed

To make the transitions clearer I also create another grid which shows the path from any cell to the end states as

‘u’ – up

‘d’ – down

‘r’ – right

‘l’ – left

Important note: If there are several alternative actions with equal value then the algorithm will break the tie randomly

In [7]:
valueMap = np.zeros((gridSize, gridSize))
valueMap1 = np.zeros((gridSize, gridSize))
states = [[i, j] for i in range(gridSize) for j in range(gridSize)]
pi = np.ones((gridSize,gridSize))/4
pi1 = np.chararray((gridSize, gridSize))
pi1[:] = 'a'
In [8]:
# Compute the value state function for the Grid
def policy_evaluate(states,actions,gamma,valueMap):
    #print("iterations=",i)
    for state in states:
        weightedRewards=0
        for action in actions:
            finalPosition,reward = actionValue(state,action)
            weightedRewards += 1/4* (reward + gamma * valueMap[finalPosition[0],finalPosition][1])
        # Set the computed weighted rewards to valueMap1
        valueMap1[state[0],state[1]]=weightedRewards
    # Copy to original valueMap
    valueMap = np.copy(valueMap1)
    return(valueMap)
In [9]:
def argmax(q_values):
    idx=np.argmax(q_values)
    return(np.random.choice(np.where(a==a[idx])[0].tolist()))


# Compute the best action in each state
def greedify_policy(state,pi,pi1,gamma,valueMap):  
        q_values=np.zeros(len(actions))
        for idx,action in enumerate(actions):
            finalPosition,reward = actionValue(state,action)
            q_values[idx] += 1/4* (reward + gamma * valueMap[finalPosition[0],finalPosition][1])
        # Find the index of the action for which the q_value is 
        idx=q_values.argmax()
        pi[state[0],state[1]]=idx 
        if(idx == 0):
            pi1[state[0],state[1]]='u'
        elif(idx == 1):
            pi1[state[0],state[1]]='d'
        elif(idx == 2):
            pi1[state[0],state[1]]='r'
        elif(idx == 3):
            pi1[state[0],state[1]]='l'

        
In [10]:
def improve_policy(pi, pi1,gamma,valueMap):
    policy_stable = True
    for state in states:
        old = pi[state].copy()
        # Greedify policy for state
        greedify_policy(state,pi,pi1,gamma,valueMap)
        if not np.array_equal(pi[state], old):
            policy_stable = False
    print(pi)
    print(pi1)
    return pi, pi1, policy_stable
In [11]:
def policy_iteration(gamma, theta):
    valueMap = np.zeros((gridSize, gridSize))
    pi = np.ones((gridSize,gridSize))/4
    pi1 = np.chararray((gridSize, gridSize))
    pi1[:] = 'a'
    policy_stable = False
    print("here")
    while not policy_stable:
        valueMap = policy_evaluate(states,actions,gamma,valueMap)
        pi,pi1, policy_stable = improve_policy(pi,pi1,  gamma,valueMap)
    return valueMap, pi,pi1
In [12]:
theta=0.1
valueMap, pi,pi1 = policy_iteration(gamma, theta)
[[0. 3. 0. 0.]
 [0. 0. 0. 0.]
 [0. 0. 0. 1.]
 [0. 0. 2. 0.]]
[[b'u' b'l' b'u' b'u']
 [b'u' b'u' b'u' b'u']
 [b'u' b'u' b'u' b'd']
 [b'u' b'u' b'r' b'u']]
[[0. 3. 3. 0.]
 [0. 0. 0. 1.]
 [0. 0. 1. 1.]
 [0. 2. 2. 0.]]
[[b'u' b'l' b'l' b'u']
 [b'u' b'u' b'u' b'd']
 [b'u' b'u' b'd' b'd']
 [b'u' b'r' b'r' b'u']]
[[0. 3. 3. 1.]
 [0. 0. 1. 1.]
 [0. 0. 1. 1.]
 [0. 2. 2. 0.]]
[[b'u' b'l' b'l' b'd']
 [b'u' b'u' b'd' b'd']
 [b'u' b'u' b'd' b'd']
 [b'u' b'r' b'r' b'u']]
[[0. 3. 3. 1.]
 [0. 0. 1. 1.]
 [0. 0. 1. 1.]
 [0. 2. 2. 0.]]
[[b'u' b'l' b'l' b'd']
 [b'u' b'u' b'd' b'd']
 [b'u' b'u' b'd' b'd']
 [b'u' b'r' b'r' b'u']]

Findings

From the above valueMap we can see that greedification solves this much faster as below

1c. Bellman Optimality update

The Bellman optimality update directly updates the value state function for the action that results in the maximum return in a state

In [13]:
gamma = 1 # discounting rate
rewardValue = -1
gridSize = 4
terminationStates = [[0,0], [gridSize-1, gridSize-1]]
actions = [[-1, 0], [1, 0], [0, 1], [0, -1]]
numIterations = 1000
In [14]:
valueMap = np.zeros((gridSize, gridSize))
valueMap1 = np.zeros((gridSize, gridSize))
states = [[i, j] for i in range(gridSize) for j in range(gridSize)]
pi = np.ones((gridSize,gridSize))/4
pi1 = np.chararray((gridSize, gridSize))
pi1[:] = 'a'
In [15]:
def bellman_optimality_update(valueMap, state, gamma):

    q_values=np.zeros(len(actions))
    
    for idx,action in enumerate(actions):
        finalPosition,reward = actionValue(state,action)
        q_values[idx] += 1/4* (reward + gamma * valueMap[finalPosition[0],finalPosition][1])
    # Find the index of the action for which the q_value is 
    idx=q_values.argmax()
            
    max = np.argmax(q_values)
    valueMap[state[0],state[1]] = q_values[max]    
    #print(q_values[max])
In [16]:
def value_iteration(gamma, theta):
    valueMap = np.zeros((gridSize, gridSize))
    while True:
        delta = 0
        for state in states:
            v_old=valueMap[state[0],state[1]]
            bellman_optimality_update(valueMap, state, gamma)
            delta = max(delta, abs(v_old - valueMap[state[0],state[1]]))
        if delta < theta:
            break
    pi = np.ones((gridSize,gridSize))/4
    for state in states:
        greedify_policy(state,pi,pi1,gamma,valueMap)
    print(pi)
    print(pi1)
    return valueMap, pi,pi1
In [17]:
gamma = 1
theta = 0.01
valueMap,pi,pi1=value_iteration(gamma, theta)
pi
pi1
[[0. 3. 3. 1.]
 [0. 0. 0. 1.]
 [0. 0. 1. 1.]
 [0. 2. 2. 0.]]
[[b'u' b'l' b'l' b'd']
 [b'u' b'u' b'u' b'd']
 [b'u' b'u' b'd' b'd']
 [b'u' b'r' b'r' b'u']]
Out[17]:
chararray([[b'u', b'l', b'l', b'd'],
           [b'u', b'u', b'u', b'd'],
           [b'u', b'u', b'd', b'd'],
           [b'u', b'r', b'r', b'u']], dtype='|S1')

Findings

The above valueMap shows the optimal path from any state

2.Gridworld 2

To make the problem more interesting, I created a 2nd grid which has more interesting structure as shown below <img src=”fig5.png”

The end state is the grey cell. Transitions to the black cells have a negative reward of -10. All other transitions have a reward of -1, while the end state has a reward of 0

In [2]:

##2a. Bellman Update

In [3]:
gamma = 1 # discounting rate
gridSize = 4

terminationStates = [[0,0]]
#terminationStates = [[0,0]]
actions = [[-1, 0], [1, 0], [0, 1], [0, -1]]
numIterations = 1000
In [4]:
rewardValue = np.zeros((gridSize,gridSize)) -1
rewardValue[0]=np.array([-1,-10,-10,-10])
rewardValue[2]=np.array([-10,-10,-10,-1])
rewardValue
Out[4]:
array([[ -1., -10., -10., -10.],
       [ -1.,  -1.,  -1.,  -1.],
       [-10., -10., -10.,  -1.],
       [ -1.,  -1.,  -1.,  -1.]])
In [5]:
def actionValue(initialPosition,action):
    if initialPosition in terminationStates:
        finalPosition = initialPosition
        reward=0
    else:
        #Compute final position
        finalPosition = np.array(initialPosition) + np.array(action)
        
        # If the action moves the finalPosition out of the grid, stay in same cell
        if -1 in finalPosition or gridSize in finalPosition:
                finalPosition = initialPosition
                reward= rewardValue[finalPosition[0],finalPosition[1]]
        else:
                reward= rewardValue[finalPosition[0],finalPosition[1]]
    
    #print(finalPosition)
    return finalPosition, reward
In [6]:
valueMap = np.zeros((gridSize, gridSize))
valueMap1 = np.zeros((gridSize, gridSize))
states = [[i, j] for i in range(gridSize) for j in range(gridSize)]
In [7]:
def policy_evaluation(numIterations,gamma,theta,valueMap):
    for i in range(numIterations):
        delta=0
        #print("iterations=",i)
        for state in states:
            weightedRewards=0
            for action in actions:
                finalPosition,reward = actionValue(state,action)
                #print("reward=",reward,"valueMap=",valueMap[finalPosition[0],finalPosition][1])
                weightedRewards += 1/4* (reward + gamma * valueMap[finalPosition[0],finalPosition][1])
            #print(weightedRewards)
            valueMap1[state[0],state[1]]=weightedRewards
            #print("wr=",weightedRewards,"va=",valueMap[state[0],state[1]]) 
            delta =max(delta,abs(weightedRewards-valueMap[state[0],state[1]]))
        valueMap = np.copy(valueMap1)
        #print(valueMap1)
        if(delta < 0.01):
            print(delta)                                                   
            print(valueMap)
            break
In [8]:
valueMap = np.zeros((gridSize, gridSize))
valueMap1 = np.zeros((gridSize, gridSize))
states = [[i, j] for i in range(gridSize) for j in range(gridSize)]
policy_evaluation(1000,1,0.0001,valueMap)
0.009862596190146178
[[   0.         -137.28514189 -209.19560831 -239.01378395]
 [-129.2494276  -180.67825796 -220.31626448 -237.86482779]
 [-194.08846546 -213.88769305 -231.5579035  -241.29920147]
 [-217.15664109 -227.25768494 -237.76348718 -241.51200989]]

2b. Greedify

In [9]:
valueMap = np.zeros((gridSize, gridSize))
valueMap1 = np.zeros((gridSize, gridSize))
states = [[i, j] for i in range(gridSize) for j in range(gridSize)]
pi = np.ones((gridSize,gridSize))/4
pi1 = np.chararray((gridSize, gridSize))
pi1[:] = 'a'
In [10]:
# Compute the value state function for the Grid
def policy_evaluate(states,actions,gamma,valueMap):
    #print("iterations=",i)
    for state in states:
        weightedRewards=0
        for action in actions:
            finalPosition,reward = actionValue(state,action)
            weightedRewards += 1/4* (reward + gamma * valueMap[finalPosition[0],finalPosition][1])
        # Set the computed weighted rewards to valueMap1
        valueMap1[state[0],state[1]]=weightedRewards
    # Copy to original valueMap
    valueMap = np.copy(valueMap1)
    return(valueMap)
In [11]:
def argmax(q_values):
    idx=np.argmax(q_values)
    return(np.random.choice(np.where(a==a[idx])[0].tolist()))


# Compute the best action in each state
def greedify_policy(state,pi,pi1,gamma,valueMap):  
        q_values=np.zeros(len(actions))
        for idx,action in enumerate(actions):
            finalPosition,reward = actionValue(state,action)
            q_values[idx] += 1/4* (reward + gamma * valueMap[finalPosition[0],finalPosition][1])
        # Find the index of the action for which the q_value is 
        idx=q_values.argmax()
        pi[state[0],state[1]]=idx 
        if(idx == 0):
            pi1[state[0],state[1]]='u'
        elif(idx == 1):
            pi1[state[0],state[1]]='d'
        elif(idx == 2):
            pi1[state[0],state[1]]='r'
        elif(idx == 3):
            pi1[state[0],state[1]]='l'

        
In [12]:
def improve_policy(pi, pi1,gamma,valueMap):
    policy_stable = True
    for state in states:
        old = pi[state].copy()
        # Greedify policy for state
        greedify_policy(state,pi,pi1,gamma,valueMap)
        if not np.array_equal(pi[state], old):
            policy_stable = False
    print(pi)
    print(pi1)
    return pi, pi1, policy_stable
In [13]:
def policy_iteration(gamma, theta):
    valueMap = np.zeros((gridSize, gridSize))
    pi = np.ones((gridSize,gridSize))/4
    pi1 = np.chararray((gridSize, gridSize))
    pi1[:] = 'a'
    policy_stable = False
    print("here")
    while not policy_stable:
        valueMap = policy_evaluate(states,actions,gamma,valueMap)
        pi,pi1, policy_stable = improve_policy(pi,pi1,  gamma,valueMap)
    return valueMap, pi,pi1
In [14]:
theta=0.1
valueMap, pi,pi1 = policy_iteration(gamma, theta)
here
[[0. 3. 1. 1.]
 [0. 3. 2. 1.]
 [0. 1. 1. 1.]
 [1. 1. 2. 1.]]
[[b'u' b'l' b'd' b'd']
 [b'u' b'l' b'r' b'd']
 [b'u' b'd' b'd' b'd']
 [b'd' b'd' b'r' b'd']]
[[0. 3. 1. 1.]
 [0. 3. 2. 1.]
 [0. 1. 1. 1.]
 [1. 2. 2. 1.]]
[[b'u' b'l' b'd' b'd']
 [b'u' b'l' b'r' b'd']
 [b'u' b'd' b'd' b'd']
 [b'd' b'r' b'r' b'd']]
[[0. 3. 1. 1.]
 [0. 3. 2. 1.]
 [0. 1. 1. 1.]
 [2. 2. 2. 1.]]
[[b'u' b'l' b'd' b'd']
 [b'u' b'l' b'r' b'd']
 [b'u' b'd' b'd' b'd']
 [b'r' b'r' b'r' b'd']]
[[0. 3. 1. 1.]
 [0. 3. 2. 1.]
 [0. 1. 1. 1.]
 [2. 2. 2. 1.]]
[[b'u' b'l' b'd' b'd']
 [b'u' b'l' b'r' b'd']
 [b'u' b'd' b'd' b'd']
 [b'r' b'r' b'r' b'd']]
In [15]:
## 2c. Bellman Optimality update
In [16]:
gamma = 1 # discounting rate
rewardValue = np.zeros((gridSize,gridSize)) -1
rewardValue[0]=np.array([-1,-10,-10,-10])
rewardValue[2]=np.array([-10,-10,-10,-1])
rewardValue
gridSize = 4
terminationStates = [[0,0]]
actions = [[-1, 0], [1, 0], [0, 1], [0, -1]]
numIterations = 1000
In [17]:
valueMap = np.zeros((gridSize, gridSize))
valueMap1 = np.zeros((gridSize, gridSize))
states = [[i, j] for i in range(gridSize) for j in range(gridSize)]
pi = np.ones((gridSize,gridSize))/4
pi1 = np.chararray((gridSize, gridSize))
pi1[:] = 'a'
In [18]:

2c. Bellman Optimality Update

def bellman_optimality_update(valueMap, state, gamma):

    q_values=np.zeros(len(actions))
    
    for idx,action in enumerate(actions):
        finalPosition,reward = actionValue(state,action)
        q_values[idx] += 1/4* (reward + gamma * valueMap[finalPosition[0],finalPosition][1])
    # Find the index of the action for which the q_value is 
    idx=q_values.argmax()
            
    max = np.argmax(q_values)
    valueMap[state[0],state[1]] = q_values[max]    
    #print(q_values[max])
In [19]:
def value_iteration(gamma, theta):
    valueMap = np.zeros((gridSize, gridSize))
    while True:
        delta = 0
        for state in states:
            v_old=valueMap[state[0],state[1]]
            bellman_optimality_update(valueMap, state, gamma)
            delta = max(delta, abs(v_old - valueMap[state[0],state[1]]))
        if delta < theta:
            break
    pi = np.ones((gridSize,gridSize))/4
    for state in states:
        greedify_policy(state,pi,pi1,gamma,valueMap)
    print(pi)
    print(pi1)
    return valueMap, pi,pi1
In [20]:
gamma = 1
theta = 0.000001
valueMap,pi,pi1=value_iteration(gamma, theta)
pi
pi1
[[0. 3. 1. 1.]
 [0. 3. 3. 3.]
 [0. 0. 0. 0.]
 [2. 2. 2. 0.]]
[[b'u' b'l' b'd' b'd']
 [b'u' b'l' b'l' b'l']
 [b'u' b'u' b'u' b'u']
 [b'r' b'r' b'r' b'u']]
Out[20]:
chararray([[b'u', b'l', b'd', b'd'],
           [b'u', b'l', b'l', b'l'],
           [b'u', b'u', b'u', b'u'],
           [b'r', b'r', b'r', b'u']], dtype='|S1')

Findings

The above shows the path from any cell to the stop cell as


3. Another maze

This is the third grid world which I create where the green cell is the end state and has a reward of 0. Transitions to the black cell will receive a reward of -10 and all other transitions will receive a reward of -1

In [2]:
gamma = 1 # discounting rate
gridSize = 5
terminationStates = [[2,2]]
actions = [[-1, 0], [1, 0], [0, 1], [0, -1]]
numIterations = 1000
In [3]:
rewardValue = np.zeros((gridSize,gridSize)) -1
rewardValue[1]=np.array([-1,-10,-1,-10,-1])
rewardValue[3]=np.array([-1,-10,-1,-10,-1])
rewardValue
Out[3]:
array([[ -1.,  -1.,  -1.,  -1.,  -1.],
       [ -1., -10.,  -1., -10.,  -1.],
       [ -1.,  -1.,  -1.,  -1.,  -1.],
       [ -1., -10.,  -1., -10.,  -1.],
       [ -1.,  -1.,  -1.,  -1.,  -1.]])
In [4]:

3a. Bellman Update

def actionValue(initialPosition,action):
    if initialPosition in terminationStates:
        finalPosition = initialPosition
        reward=0
    else:
        #Compute final position
        finalPosition = np.array(initialPosition) + np.array(action)
        
        # If the action moves the finalPosition out of the grid, stay in same cell
        if -1 in finalPosition or gridSize in finalPosition:
                finalPosition = initialPosition
                reward= rewardValue[finalPosition[0],finalPosition[1]]
        else:
                reward= rewardValue[finalPosition[0],finalPosition[1]]
    
    #print(finalPosition)
    return finalPosition, reward
In [5]:
valueMap = np.zeros((gridSize, gridSize))
valueMap1 = np.zeros((gridSize, gridSize))
states = [[i, j] for i in range(gridSize) for j in range(gridSize)]
In [6]:
def policy_evaluation(numIterations,gamma,theta,valueMap):
    for i in range(numIterations):
        delta=0
        #print("iterations=",i)
        for state in states:
            weightedRewards=0
            for action in actions:
                finalPosition,reward = actionValue(state,action)
                #print("reward=",reward,"valueMap=",valueMap[finalPosition[0],finalPosition][1])
                weightedRewards += 1/4* (reward + gamma * valueMap[finalPosition[0],finalPosition][1])
            #print(weightedRewards)
            valueMap1[state[0],state[1]]=weightedRewards
            #print("wr=",weightedRewards,"va=",valueMap[state[0],state[1]]) 
            delta =max(delta,abs(weightedRewards-valueMap[state[0],state[1]]))
        valueMap = np.copy(valueMap1)
        #print(valueMap1)
        if(delta < 0.01):
            print(delta)                                                   
            print(valueMap)
            break
In [7]:
valueMap = np.zeros((gridSize, gridSize))
valueMap1 = np.zeros((gridSize, gridSize))
states = [[i, j] for i in range(gridSize) for j in range(gridSize)]
policy_evaluation(1000,1,0.0001,valueMap)
0.009697101372182715
[[-82.49768079 -80.51647225 -74.9345659  -80.51647225 -82.49768079]
 [-80.51647225 -71.15241689 -59.80375072 -71.15241689 -80.51647225]
 [-74.9345659  -59.80375072   0.         -59.80375072 -74.9345659 ]
 [-80.51647225 -71.15241689 -59.80375072 -71.15241689 -80.51647225]
 [-82.49768079 -80.51647225 -74.9345659  -80.51647225 -82.49768079]]

3b. Greedify

In [8]:
valueMap = np.zeros((gridSize, gridSize))
valueMap1 = np.zeros((gridSize, gridSize))
states = [[i, j] for i in range(gridSize) for j in range(gridSize)]
pi = np.ones((gridSize,gridSize))/4
pi1 = np.chararray((gridSize, gridSize))
pi1[:] = 'a'
In [9]:
# Compute the value state function for the Grid
def policy_evaluate(states,actions,gamma,valueMap):
    #print("iterations=",i)
    for state in states:
        weightedRewards=0
        for action in actions:
            finalPosition,reward = actionValue(state,action)
            weightedRewards += 1/4* (reward + gamma * valueMap[finalPosition[0],finalPosition][1])
        # Set the computed weighted rewards to valueMap1
        valueMap1[state[0],state[1]]=weightedRewards
    # Copy to original valueMap
    valueMap = np.copy(valueMap1)
    return(valueMap)
In [10]:
def argmax(q_values):
    idx=np.argmax(q_values)
    return(np.random.choice(np.where(a==a[idx])[0].tolist()))


# Compute the best action in each state
def greedify_policy(state,pi,pi1,gamma,valueMap):  
        q_values=np.zeros(len(actions))
        for idx,action in enumerate(actions):
            finalPosition,reward = actionValue(state,action)
            q_values[idx] += 1/4* (reward + gamma * valueMap[finalPosition[0],finalPosition][1])
        # Find the index of the action for which the q_value is 
        idx=q_values.argmax()
        pi[state[0],state[1]]=idx 
        if(idx == 0):
            pi1[state[0],state[1]]='u'
        elif(idx == 1):
            pi1[state[0],state[1]]='d'
        elif(idx == 2):
            pi1[state[0],state[1]]='r'
        elif(idx == 3):
            pi1[state[0],state[1]]='l'

        
In [11]:
def improve_policy(pi, pi1,gamma,valueMap):
    policy_stable = True
    for state in states:
        old = pi[state].copy()
        # Greedify policy for state
        greedify_policy(state,pi,pi1,gamma,valueMap)
        if not np.array_equal(pi[state], old):
            policy_stable = False
    print(pi)
    print(pi1)
    return pi, pi1, policy_stable
In [12]:
def policy_iteration(gamma, theta):
    valueMap = np.zeros((gridSize, gridSize))
    pi = np.ones((gridSize,gridSize))/4
    pi1 = np.chararray((gridSize, gridSize))
    pi1[:] = 'a'
    policy_stable = False
    print("here")
    while not policy_stable:
        valueMap = policy_evaluate(states,actions,gamma,valueMap)
        pi,pi1, policy_stable = improve_policy(pi,pi1,  gamma,valueMap)
    return valueMap, pi,pi1
In [13]:
theta=0.1
valueMap, pi,pi1 = policy_iteration(gamma, theta)
here
[[0. 2. 0. 2. 0.]
 [0. 0. 1. 0. 0.]
 [3. 2. 0. 3. 2.]
 [0. 1. 0. 1. 0.]
 [1. 2. 1. 2. 1.]]
[[b'u' b'r' b'u' b'r' b'u']
 [b'u' b'u' b'd' b'u' b'u']
 [b'l' b'r' b'u' b'l' b'r']
 [b'u' b'd' b'u' b'd' b'u']
 [b'd' b'r' b'd' b'r' b'd']]
[[0. 3. 0. 2. 0.]
 [0. 0. 1. 0. 0.]
 [3. 2. 0. 3. 2.]
 [1. 1. 0. 1. 1.]
 [1. 3. 1. 2. 1.]]
[[b'u' b'l' b'u' b'r' b'u']
 [b'u' b'u' b'd' b'u' b'u']
 [b'l' b'r' b'u' b'l' b'r']
 [b'd' b'd' b'u' b'd' b'd']
 [b'd' b'l' b'd' b'r' b'd']]
[[0. 3. 0. 2. 0.]
 [0. 0. 1. 0. 0.]
 [3. 2. 0. 3. 2.]
 [1. 1. 0. 1. 1.]
 [1. 3. 1. 2. 1.]]
[[b'u' b'l' b'u' b'r' b'u']
 [b'u' b'u' b'd' b'u' b'u']
 [b'l' b'r' b'u' b'l' b'r']
 [b'd' b'd' b'u' b'd' b'd']
 [b'd' b'l' b'd' b'r' b'd']]
In [14]:
gamma = 1 # discounting rate
gridSize=5
rewardValue = np.zeros((gridSize,gridSize)) -1
rewardValue = np.zeros((gridSize,gridSize)) -1
rewardValue[1]=np.array([-1,-10,-1,-10,-1])
rewardValue[3]=np.array([-1,-10,-1,-10,-1])
print(rewardValue)


terminationStates = [[2,2]]
actions = [[-1, 0], [1, 0], [0, 1], [0, -1]]
numIterations = 1000
[[ -1.  -1.  -1.  -1.  -1.]
 [ -1. -10.  -1. -10.  -1.]
 [ -1.  -1.  -1.  -1.  -1.]
 [ -1. -10.  -1. -10.  -1.]
 [ -1.  -1.  -1.  -1.  -1.]]
In [15]:

3c. Bellman Optimality Update

valueMap = np.zeros((gridSize, gridSize))
valueMap1 = np.zeros((gridSize, gridSize))
states = [[i, j] for i in range(gridSize) for j in range(gridSize)]
pi = np.ones((gridSize,gridSize))/4
pi1 = np.chararray((gridSize, gridSize))
pi1[:] = 'a'
In [16]:
def bellman_optimality_update(valueMap, state, gamma):

    q_values=np.zeros(len(actions))
    
    for idx,action in enumerate(actions):
        finalPosition,reward = actionValue(state,action)
        q_values[idx] += 1/4* (reward + gamma * valueMap[finalPosition[0],finalPosition][1])
    # Find the index of the action for which the q_value is 
    idx=q_values.argmax()
            
    max = np.argmax(q_values)
    valueMap[state[0],state[1]] = q_values[max]    
    #print(q_values[max])
In [17]:
def value_iteration(gamma, theta):
    valueMap = np.zeros((gridSize, gridSize))
    while True:
        delta = 0
        for state in states:
            v_old=valueMap[state[0],state[1]]
            bellman_optimality_update(valueMap, state, gamma)
            delta = max(delta, abs(v_old - valueMap[state[0],state[1]]))
        if delta < theta:
            break
    pi = np.ones((gridSize,gridSize))/4
    for state in states:
        greedify_policy(state,pi,pi1,gamma,valueMap)
    print(pi)
    print(pi1)
    return valueMap, pi,pi1
In [18]:
gamma = 1
theta = 0.000001
valueMap,pi,pi1=value_iteration(gamma, theta)
pi
pi1
[[1. 2. 1. 3. 1.]
 [1. 1. 1. 1. 1.]
 [2. 2. 0. 3. 3.]
 [0. 0. 0. 0. 0.]
 [0. 2. 0. 3. 0.]]
[[b'd' b'r' b'd' b'l' b'd']
 [b'd' b'd' b'd' b'd' b'd']
 [b'r' b'r' b'u' b'l' b'l']
 [b'u' b'u' b'u' b'u' b'u']
 [b'u' b'r' b'u' b'l' b'u']]
Out[18]:
chararray([[b'd', b'r', b'd', b'l', b'd'],
           [b'd', b'd', b'd', b'd', b'd'],
           [b'r', b'r', b'u', b'l', b'l'],
           [b'u', b'u', b'u', b'u', b'u'],
           [b'u', b'r', b'u', b'l', b'u']], dtype='|S1')


Findings

We can see that the Bellman Optimality Update correctly finds the path the to end node which we can see from the valueMap1 above which is

Conclusion:

We can see how with the Bellman equations implemented iteratively with dynamic programming we can solve mazes of arbitrary shapes and complexities as long as we correctly choose the reward for the transitions

References
1. Reinforcement learning – An introduction by Richard S. Sutton and Andrew G Barto
2. Reinforcement learning (RL) 101 with Python Blog by Gerard Martinez
3. Reinforcement Learning Demystified: Solving MDPs with Dynamic Programming Blog by Mohammed Ashraf

You may also like

1. My book ‘Deep Learning from first principles:Second Edition’ now on Amazon
2. Big Data-4: Webserver log analysis with RDDs, Pyspark, SparkR and SparklyR
3. Practical Machine Learning with R and Python – Part 3
3. Pitching yorkpy…on the middle and outside off-stump to IPL – Part 2
4. Sixer – R package cricketr’s new Shiny avatar
5. Natural language processing: What would Shakespeare say?
6. Getting started with Tensorflow, Keras in Python and R

To see all posts click Index of posts

Cricpy performs granular analysis of players

“Gold medals aren’t really made of gold. They’re made of sweat, determination, & a hard-to-find alloy called guts.” Dan Gable

“It doesn’t matter whether you are pursuing success in business, sports, the arts, or life in general: The bridge between wishing and accomplishing is discipline” Harvey Mackay

“I won’t predict anything historic. But nothing is impossible.” Michael Phelps

Introduction

In this post, I introduce 2 new functions in my Python package ‘cricpy’ (cricpy v0.20) see Introducing cricpy:A python package to analyze performances of cricketers which enable granular analysis of batsmen and bowlers. They are

  1. Step 1: getPlayerDataHA – This function is a wrapper around getPlayerData(), getPlayerDataOD() and getPlayerDataTT(), and adds an extra column ‘homeOrAway’ which says whether the match was played at home/away/neutral venues. A CSV file is created with this new column.
  2. Step 2: getPlayerDataOppnHA – This function allows you to slice & dice the data for batsmen and bowlers against specific oppositions, at home/away/neutral venues and between certain periods. This reducedsubset of data can be used to perform analyses. A CSV file is created as an output based on the parameters of opposition, home or away and the interval of time

Note All the existing cricpy functions can be used on this smaller fine-grained data set for a closer analysis of players

This post has been published in Rpubs and can be accessed at Cricpy performs granular analysis of players

You can download a PDF version of this post at Cricpy performs granular analysis of players

I have also updated the cricpy template with these lastest changes. See cricpy-template

1. Analyzing Rahul Dravid at 3 different stages of his career

The following functions analyze Rahul Dravid during 3 different periods of his illustrious career. a) 1st Jan 2001-1st Jan 2002 b) 1st Jan 2004-1st Jan 2005 c) 1st Jan 2009-1st Jan 2010

import cricpy.analytics as ca
# Get the homeOrAway dataset for Dravid in matches
# Note:Since I have already got the data I reuse the CSV file
#df=ca.getPlayerDataHA(28114,tfile="dravidTestHA.csv",matchType="Test")

# Get Dravid's data for 2001-02
df1=ca.getPlayerDataOppnHA(infile="dravidTestHA.csv",outfile="dravidTest2001.csv",startDate="2001-01-01",endDate="2002-01-01")

# Get Dravid's data for 2004-05
df2=ca.getPlayerDataOppnHA(infile="dravidTestHA.csv",outfile="dravidTest2004.csv", startDate="2004-01-01",endDate="2005-01-01")

# Get Dravid's data for 2009-10
df3=ca.getPlayerDataOppnHA(infile="dravidTestHA.csv",outfile="dravidTest2009.csv",startDate="2009-01-01",endDate="2010-01-01")

1a. Plot the performance of Dravid at venues during 2001,2004,2009

Note: Any of the cricpy functions can be used on the fine-grained subset of data as below.

import cricpy.analytics as ca
ca.batsmanAvgRunsGround("dravidTest2001.csv","Dravid-2001")

ca.batsmanAvgRunsGround("dravidTest2004.csv","Dravid-2004")

ca.batsmanAvgRunsGround("dravidTest2009.csv","Dravid-2009")


1b. Plot the performance of Dravid against different oppositions during 2001,2004,2009

import cricpy.analytics as ca
ca.batsmanAvgRunsOpposition("dravidTest2001.csv","Dravid-2001")

ca.batsmanAvgRunsOpposition("dravidTest2004.csv","Dravid-2004")


ca.batsmanAvgRunsOpposition("dravidTest2009.csv","Dravid-2009")


1c. Plot the relative cumulative average and relative strike rate of Dravid in 2001,2004,2009

The plot below compares Dravid’s cumulative strike rate and cumulative average during 3 different stages of his career

import cricpy.analytics as ca
frames=["dravidTest2001.csv","dravidTest2004.csv","dravidTest2009.csv"]
names=["Dravid-2001","Dravid-2004","Dravid-2009"]
ca.relativeBatsmanCumulativeAvgRuns(frames,names)

 

ca.relativeBatsmanCumulativeStrikeRate(frames,names)

2. Analyzing Virat Kohli’s performance against England in England in 2014 and 2018

The analysis below looks at Kohli’s performance against England in ‘away’ venues (England) in 2014 and 2018

import cricpy.analytics as ca
# Get the homeOrAway data for Kohli in Test matches
#df=ca.getPlayerDataHA(253802,tfile="kohliTestHA.csv",type="batting",matchType="Test")

# Get the homeOrAway data for Kohli in Test matches
df=ca.getPlayerDataHA(253802,tfile="kohliTestHA.csv",type="batting",matchType="Test")

# Get the subset if data of Kohli's performance against England in England in 2014
df=ca.getPlayerDataOppnHA(infile="kohliTestHA.csv",outfile="kohliTestEng2014.csv",  opposition=["England"],homeOrAway=["away"],startDate="2014-01-01",endDate="2015-01-01")

# Get the subset if data of Kohli's performance against England in England in 2018
df1=ca.getPlayerDataOppnHA(infile="kohliTestHA.csv",outfile="kohliTestEng2018.csv",
   opposition=["England"],homeOrAway=["away"],startDate="2018-01-01",endDate="2019-01-01")

2a. Kohli’s performance at England grounds in 2014 & 2018

Kohli had a miserable outing to England in 2014 with a string of low scores. In 2018 Kohli pulls himself out of the morass

import cricpy.analytics as ca
ca.batsmanAvgRunsGround("kohliTestEng2014.csv","Kohli-Eng-2014")
ca.batsmanAvgRunsGround("kohliTestEng2018.csv","Kohli-Eng-2018")


2a. Kohli’s cumulative average runs in 2014 & 2018

Kohli’s cumulative average runs in 2014 is in the low 15s, while in 2018 it is 70+. Kohli stamps his class back again and undoes the bad memories of 2014

import cricpy.analytics as ca
ca.batsmanCumulativeAverageRuns("kohliTestEng2014.csv", "Kohli-Eng-2014")

ca.batsmanCumulativeAverageRuns("kohliTestEng2018.csv", "Kohli-Eng-2018")

3a. Compare the performances of Ganguly, Dravid and VVS Laxman against opposition in ‘away’ matches in Tests

The analyses below compares the performances of Sourav Ganguly, Rahul Dravid and VVS Laxman against Australia, South Africa, and England in ‘away’ venues between 01 Jan 2002 to 01 Jan 2008

import cricpy.analytics as ca
#Get the HA data for Ganguly, Dravid and Laxman
#df=ca.getPlayerDataHA(28779,tfile="gangulyTestHA.csv",type="batting",matchType="Test")
#df=ca.getPlayerDataHA(28114,tfile="dravidTestHA.csv",type="batting",matchType="Test")
#df=ca.getPlayerDataHA(30750,tfile="laxmanTestHA.csv",type="batting",matchType="Test")

# Slice the data 
df=ca.getPlayerDataOppnHA(infile="gangulyTestHA.csv",outfile="gangulyTestAES2002-08.csv" ,opposition=["Australia", "England", "South Africa"],                        homeOrAway=["away"],startDate="2002-01-01",endDate="2008-01-01")
df=ca.getPlayerDataOppnHA(infile="dravidTestHA.csv",outfile="dravidTestAES2002-08.csv" ,opposition=["Australia", "England", "South Africa"],                        homeOrAway=["away"],startDate="2002-01-01",endDate="2008-01-01")
df=ca.getPlayerDataOppnHA(infile="laxmanTestHA.csv",outfile="laxmanTestAES2002-08.csv",opposition=["Australia", "England", "South Africa"],                       homeOrAway=["away"],startDate="2002-01-01",endDate="2008-01-01")

3b Plot the relative cumulative average runs and relative cumative strike rate

Plot the relative cumulative average runs and relative cumative strike rate of Ganguly, Dravid and Laxman

-Dravid towers over Laxman and Ganguly with respect to cumulative average runs. – Ganguly has a superior strike rate followed by Laxman and then Dravid

import cricpy.analytics as ca
frames=["gangulyTestAES2002-08.csv","dravidTestAES2002-08.csv","laxmanTestAES2002-08.csv"]
names=["GangulyAusEngSA2002-08","DravidAusEngSA2002-08","LaxmanAusEngSA2002-08"]
ca.relativeBatsmanCumulativeAvgRuns(frames,names)

ca.relativeBatsmanCumulativeStrikeRate(frames,names)

4. Compare the ODI performances of Rohit Sharma, Joe Root and Kane Williamson against opposition

Compare the performances of Rohit Sharma, Joe Root and Kane williamson in away & neutral venues against Australia, West Indies and Soouth Africa

  • Joe Root piles us the runs in about 15 matches. Rohit has played far more ODIs than the other two and averages a steady 35+
import cricpy.analytics as ca
# Get the ODI HA data for Rohit, Root and Williamson
#df=ca.getPlayerDataHA(34102,tfile="rohitODIHA.csv",type="batting",matchType="ODI")
#df=ca.getPlayerDataHA(303669,tfile="joerootODIHA.csv",type="batting",matchType="ODI")
#df=ca.getPlayerDataHA(277906,tfile="williamsonODIHA.csv",type="batting",matchType="ODI")

# Subset the data for specific opposition in away and neutral venues
## C:\Users\Ganesh\ANACON~1\lib\site-packages\statsmodels\compat\pandas.py:56: FutureWarning: The pandas.core.datetools module is deprecated and will be removed in a future version. Please use the pandas.tseries module instead.
##   from pandas.core import datetools
df=ca.getPlayerDataOppnHA(infile="rohitODIHA.csv",outfile="rohitODIAusWISA.csv"
                       ,opposition=["Australia", "West Indies", "South Africa"],
                      homeOrAway=["away","neutral"])
df=ca.getPlayerDataOppnHA(infile="joerootODIHA.csv",outfile="joerootODIAusWISA.csv"
                       ,opposition=["Australia", "West Indies", "South Africa"],
                       homeOrAway=["away","neutral"])
df=ca.getPlayerDataOppnHA(infile="williamsonODIHA.csv",outfile="williamsonODIAusWiSA.csv",opposition=["Australia", "West Indies", "South Africa"],                    homeOrAway=["away","neutral"])

4a. Compare cumulative strike rates and cumulative average runs of Rohit, Root and Williamson

The relative cumulative strike rate of all 3 are comparable

import cricpy.analytics as ca
frames=["rohitODIAusWISA.csv","joerootODIAusWISA.csv","williamsonODIAusWiSA.csv"]
names=["Rohit-ODI-AusWISA","Joe Root-ODI-AusWISA","Williamson-ODI-AusWISA"]
ca.relativeBatsmanCumulativeAvgRuns(frames,names)

ca.relativeBatsmanCumulativeStrikeRate(frames,names)

5. Plot the performance of Dhoni in T20s against specific opposition at all venues

Plot the performances of Dhoni against Australia, West Indies, South Africa and England

import cricpy.analytics as ca
# Get the HA T20 data for Dhoni
#df=ca.getPlayerDataHA(28081,tfile="dhoniT20HA.csv",type="batting",matchType="T20")
#Subset the data
df=ca.getPlayerDataOppnHA(infile="dhoniT20HA.csv",outfile="dhoniT20AusWISAEng.csv",opposition=["Australia", "West Indies", "South Africa","England"],                homeOrAway=["all"])

5a. Plot Dhoni’s performances in T20

Note You can use any of cricpy’s functions against the fine grained data

import cricpy.analytics as ca
ca.batsmanAvgRunsOpposition("dhoniT20AusWISAEng.csv","Dhoni")

ca.batsmanAvgRunsGround("dhoniT20AusWISAEng.csv","Dhoni")

ca.batsmanCumulativeStrikeRate("dhoniT20AusWISAEng.csv","Dhoni")

ca.batsmanCumulativeAverageRuns("dhoniT20AusWISAEng.csv","Dhoni")

6. Compute and performances of Anil Kumble, Muralitharan and Warne in ‘away’ test matches

Compute the performances of Kumble, Warne and Maralitharan against New Zealand, West Indies, South Africa and England in pitches that are not ‘home’ pithes

import cricpy.analytics as ca
# Get the bowling data for Kumble, Warne and Muralitharan in Test matches
#df=ca.getPlayerDataHA(30176,tfile="kumbleTestHA.csv",type="bowling",matchType="Test")
#df=ca.getPlayerDataHA(8166,tfile="warneTestHA.csv",type="bowling",matchType="Test")
#df=ca.getPlayerDataHA(49636,tfile="muraliTestHA.csv",type="bowling",matchType="Test")

# Subset the data
df=ca.getPlayerDataOppnHA(infile="kumbleTestHA.csv",outfile="kumbleTest-NZWISAEng.csv",opposition=["New Zealand", "West Indies", "South Africa","England"],
                       homeOrAway=["away"])

df=ca.getPlayerDataOppnHA(infile="warneTestHA.csv",outfile="warneTest-NZWISAEng.csv"
                       ,opposition=["New Zealand", "West Indies", "South Africa","England"], homeOrAway=["away"])

df=ca.getPlayerDataOppnHA(infile="muraliTestHA.csv",outfile="muraliTest-NZWISAEng.csv"
                       ,opposition=["New Zealand", "West Indies", "South Africa","England"], homeOrAway=["away"])

6a. Plot the average wickets of Kumble, Warne and Murali

import cricpy.analytics as ca
ca.bowlerAvgWktsOpposition("kumbleTest-NZWISAEng.csv","Kumble-NZWISAEng-AN")

ca.bowlerAvgWktsOpposition("warneTest-NZWISAEng.csv","Warne-NZWISAEng-AN")

ca.bowlerAvgWktsOpposition("muraliTest-NZWISAEng.csv","Murali-NZWISAEng-AN")

6b. Plot the average wickets in different grounds of Kumble, Warne and Murali

import cricpy.analytics as ca
ca.bowlerAvgWktsGround("kumbleTest-NZWISAEng.csv","Kumble")

ca.bowlerAvgWktsGround("warneTest-NZWISAEng.csv","Warne")

ca.bowlerAvgWktsGround("muraliTest-NZWISAEng.csv","Murali")

6c. Plot the cumulative average wickets and cumulative economy rate of Kumble, Warne and Murali

  • Murali has the best economy rate followed by Kumble and then Warne
  • Again Murali has the best cumulative average wickets followed by Warne and then Kumble
import cricpy.analytics as ca
frames=["kumbleTest-NZWISAEng.csv","warneTest-NZWISAEng.csv","muraliTest-NZWISAEng.csv"]
names=["Kumble","Warne","Murali"]
ca.relativeBowlerCumulativeAvgEconRate(frames,names)

ca.relativeBowlerCumulativeAvgWickets(frames,names)

7. Compute and plot the performances of Bumrah in 2016, 2017 and 2018 in ODIs

import cricpy.analytics as ca
# Get the HA data for Bumrah in ODI in bowling
#df=ca.getPlayerDataHA(625383,tfile="bumrahODIHA.csv",type="bowling",matchType="ODI")

# Slice the data for periods 2016, 2017 and 2018
df=ca.getPlayerDataOppnHA(infile="bumrahODIHA.csv",outfile="bumrahODI2016.csv",
                       startDate="2016-01-01",endDate="2017-01-01")

df=ca.getPlayerDataOppnHA(infile="bumrahODIHA.csv",outfile="bumrahODI2017.csv",
                       startDate="2017-01-01",endDate="2018-01-01")

df=ca.getPlayerDataOppnHA(infile="bumrahODIHA.csv",outfile="bumrahODI2018.csv",
                       startDate="2018-01-01",endDate="2019-01-01")

7a. Compute the performances of Bumrah in 2016, 2017 and 2018

  • Very clearly Bumrah is getting better at his art. His economy rate in 2018 is the best!!!
  • Bumrah has had a very prolific year in 2017. However all the years he seems to be quite effective
import cricpy.analytics as ca
frames=["bumrahODI2016.csv","bumrahODI2017.csv","bumrahODI2018.csv"]
names=["Bumrah-2016","Bumrah-2017","Bumrah-2018"]
ca.relativeBowlerCumulativeAvgEconRate(frames,names)

ca.relativeBowlerCumulativeAvgWickets(frames,names)

8. Compute and plot the performances of Shakib, Bumrah and Jadeja in T20 matches for bowling

import cricpy.analytics as ca
# Get the HA bowling data for Shakib, Bumrah and Jadeja
#df=ca.getPlayerDataHA(56143,tfile="shakibT20HA.csv",type="bowling",matchType="T20")
#df=ca.getPlayerDataHA(625383,tfile="bumrahT20HA.csv",type="bowling",matchType="T20")
#df=ca.getPlayerDataHA(234675,tfile="jadejaT20HA.csv",type="bowling",matchType="T20")

# Slice the data for performances against Sri Lanka, Australia, South Africa and England
df=ca.getPlayerDataOppnHA(infile="shakibT20HA.csv",outfile="shakibT20-SLAusSAEng.csv" ,opposition=["Sri Lanka","Australia", "South Africa","England"],
                       homeOrAway=["all"])
df=ca.getPlayerDataOppnHA(infile="bumrahT20HA.csv",outfile="bumrahT20-SLAusSAEng.csv",opposition=["Sri Lanka","Australia", "South Africa","England"],
                       homeOrAway=["all"])

df=ca.getPlayerDataOppnHA(infile="jadejaT20HA.csv",outfile="jadejaT20-SLAusSAEng.csv"                      ,opposition=["Sri Lanka","Australia", "South Africa","England"],   homeOrAway=["all"])

8a. Compare the relative performances of Shakib, Bumrah and Jadeja

  • Jadeja and Bumrah have comparable economy rates. Shakib is more expensive
  • Shakib pips Bumrah in number of cumulative wickets, though Bumrah is close behind
import cricpy.analytics as ca
frames=["shakibT20-SLAusSAEng.csv","bumrahT20-SLAusSAEng.csv","jadejaT20-SLAusSAEng.csv"]
names=["Shakib-SLAusSAEng","Bumrah-SLAusSAEng","Jadeja-SLAusSAEng"]
ca.relativeBowlerCumulativeAvgEconRate(frames,names)

ca.relativeBowlerCumulativeAvgWickets(frames,names)

Conclusion

By getting the homeOrAway data for players using the profileNo, you can slice and dice the data based on your choice of opposition, whether you want matches that were played at home/away/neutral venues. Finally by specifying the period for which the data has to be subsetted you can create fine grained analysis.

Hope you have a great time with cricpy!!!

Also see
1. My book ‘Cricket analytics with cricketr and cricpy’ is now on Amazon
2. The 3rd paperback & kindle editions of my books on Cricket, now on Amazon
3. Exploring Quantum Gate operations with QCSimulator
4. Deep Learning from first principles in Python, R and Octave – Part 6
5. Natural selection of database technology through the years
6. Pitching yorkpy … short of good length to IPL – Part 1
7. Using Linear Programming (LP) for optimizing bowling change or batting lineup in T20 cricket
8. Practical Machine Learning with R and Python – Part 3

To see all posts click Index of posts