Book Image

Statistics for Machine Learning

By : Pratap Dangeti
Book Image

Statistics for Machine Learning

By: Pratap Dangeti

Overview of this book

Complex statistics in machine learning worry a lot of developers. Knowing statistics helps you build strong machine learning models that are optimized for a given problem statement. This book will teach you all it takes to perform the complex statistical computations that are required for machine learning. You will gain information on the statistics behind supervised learning, unsupervised learning, reinforcement learning, and more. You will see real-world examples that discuss the statistical side of machine learning and familiarize yourself with it. You will come across programs for performing tasks such as modeling, parameter fitting, regression, classification, density collection, working with vectors, matrices, and more. By the end of the book, you will have mastered the statistics required for machine learning and will be able to apply your new skills to any sort of industry problem.
Table of Contents (16 chapters)
Title Page
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Random forest classifier - grid search


Tuning parameters in a machine learning model plays a critical role. Here, we are showing a grid search example on how to tune a random forest model:

# Random Forest Classifier - Grid Search 
>>> from sklearn.pipeline import Pipeline 
>>> from sklearn.model_selection import train_test_split,GridSearchCV 
 
>>> pipeline = Pipeline([ ('clf',RandomForestClassifier(criterion='gini',class_weight = {0:0.3,1:0.7}))])

Tuning parameters are similar to random forest parameters apart from verifying all the combinations using the pipeline function. The number of combinations to be evaluated will be (3 x 3 x 2 x 2) *5 =36*5 = 180 combinations. Here 5 is used in the end, due to the cross validation of five-fold:

>>> parameters = { 
...         'clf__n_estimators':(2000,3000,5000), 
...         'clf__max_depth':(5,15,30), 
...         'clf__min_samples_split':(2,3), 
...         'clf__min_samples_leaf':(1,2)  } 

>>> grid_search...