Search icon CANCEL
Subscription
0
Cart icon
Your Cart (0 item)
Close icon
You have no products in your basket yet
Arrow left icon
Explore Products
Best Sellers
New Releases
Books
Videos
Audiobooks
Learning Hub
Free Learning
Arrow right icon
Arrow up icon
GO TO TOP
Statistics for Machine Learning

You're reading from   Statistics for Machine Learning Techniques for exploring supervised, unsupervised, and reinforcement learning models with Python and R

Arrow left icon
Product type Paperback
Published in Jul 2017
Publisher Packt
ISBN-13 9781788295758
Length 442 pages
Edition 1st Edition
Languages
Arrow right icon
Author (1):
Arrow left icon
Pratap Dangeti Pratap Dangeti
Author Profile Icon Pratap Dangeti
Pratap Dangeti
Arrow right icon
View More author details
Toc

Table of Contents (10) Chapters Close

Preface 1. Journey from Statistics to Machine Learning FREE CHAPTER 2. Parallelism of Statistics and Machine Learning 3. Logistic Regression Versus Random Forest 4. Tree-Based Machine Learning Models 5. K-Nearest Neighbors and Naive Bayes 6. Support Vector Machines and Neural Networks 7. Recommendation Engines 8. Unsupervised Learning 9. Reinforcement Learning

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...
lock icon The rest of the chapter is locked
Register for a free Packt account to unlock a world of extra content!
A free Packt account unlocks extra newsletters, articles, discounted offers, and much more. Start advancing your knowledge today.
Unlock this book and the full library FREE for 7 days
Get unlimited access to 7000+ expert-authored eBooks and videos courses covering every tech area you can think of
Renews at $19.99/month. Cancel anytime
Banner background image