", Classification_report (Gbc_y_predict, Y_test, target_names=['died','survived']))103 104 " " the Single decision tree accuracy: 0.7811550151975684106 Other indicators:107 Precision recall F1-score support108 109 died 0.91 0.78 0.84 236 the survived 0.58 0.80 0.67111 the avg/total 0.81 0.78 0.79 329113 the Random forest accuracy: 0.78419452887538 the Other indicators: the Precision recall F1-score suppor
[Ai refining] machine learning 051-bag of Vision Model + extreme random forest to build an image classifier
(Python library and version number used in this article: Python 3.6, numpy 1.14, scikit-learn 0.19, matplotlib 2.2)
Bag of visual words (bovw) comes from bag of words
The random forest algorithm and summary implemented by Python, And the python forest Algorithm
This example describes the random forest algorithm implemented by
Random forest classifier:
Introduction to the algorithm:
Stochastic forest is an integrated algorithm of decision tree. Random forests contain multiple decision trees to reduce the risk of fitting. Stochastic forest has the charac
],[4.0,5.0,6.0])) " "#Split the data into training and test sets (30% held out for testing) splits the dataset, leaving 30% as the test set(Trainingdata, TestData) = Data.randomsplit ([0.7, 0.3])#Train a randomforest model. Training Decision Tree Models#empty categoricalfeaturesinfo indicates all features is continuous. Null categoricalfeaturesinfo means that all features are continuous#note:use larger numtrees in practice. Note: More trees can be used in practice#Setting featuresubsetstrategy=
Python decision tree and random forest algorithm examples
This article describes Python decision tree and random forest algorithms. We will share this with you for your reference. The details are as follows:
Decision Trees and
Stochastic forest is a very flexible machine learning method, which has many applications from marketing to medical insurance. It can be used for marketing to model or predict the patient's disease risk and susceptibility to customer acquisition and retention.
Random forests can be used for classification and regression problems, can handle a large number of features, and can help estimate the importance o
The local sensitive hashing algorithm was previously implemented with the R language, but because of its low performance in R, the LSH was discarded for similarity retrieval. Learn python found a lot of modules can be achieved, and by random projection of the forest to make query data faster, think you can try to large-scale application in the data similarity ret
algorithm (LSH) solves the problem of mechanical similarity of text (I, basic principle)The R language implements the ︱ local sensitive hashing algorithm (LSH) to solve textual mechanical similarity problems (two. Textreuse introduction)The four parts of the mechanical-similar Python version:Lsh︱python realization of locally sensitive random projection
data has the opportunity to be extracted again. It works well in cases where the number of samples is not much.Other similar algorithms1.BaggingThe bagging algorithm is similar to a random forest, except that each tree uses all features rather than just a subset of the features. The algorithm process is as follows:1) n samples are selected randomly from sample set;2) on all attributes, set up the
(such as sample size, shape and element composition, etc.) obtained by the molecule descriptor, the descriptor has been normalized.First time CommitThe game is a two-dollar classification problem whose data has been extracted and selected to make preprocessing easier, and although the game is over, you can still submit a solution so you can see comparisons with the world's best data scientists.Here, I use the random
:
When splitting, find the splitting variable and the splitting point that make the purity drop the fastest.
From the results, it can be seen that the cart can be iterated through variable selection to create a classification tree, so that each classification plane can best divide the remaining data into two categories.
Classification tree is very simple, but there are often noisy classifiers. So introduced ensemble classifiers:bagging, Ran
make a summary of the flow of the bagging algorithm. The AdaBoost and gbdt,bagging algorithms are much simpler relative to the boosting series.Input as Sample set $d=\{(X_,y_1), (x_2,y_2), ... (X_m,y_m) \}$, weak learner algorithm, weak classifier iteration number T.Output is the final strong classifier $f (x) $1) for t=1,2...,t:A) a T random sampling of the tra
Below is the calculation
Calculation below
3. Recursive Construction decision tree
When all the features are used up, a majority voting method is used to determine the classification of the leaf node, that is, the leaf node belongs to a certain class of the maximum number of samples, then we say that the leaf node belongs to that category!
Create Tree
To run t
Awesome Random ForestRandom forest-a curated list of resources regarding tree-based methods and more, including-not limited-to-random for EST, bagging and boosting.ContributingPlease feel free-to-pull requests, email Jung Kwon Lee ([e-Mail protected]) or join our chats to add links.Table of Contents
Codes
Theory
Lectures
Books
attribute has a stronger ability to reduce the entropy of the sample, which makes the data more capable of becoming deterministic from uncertainty .?1.3 Decision tree over-fittingThe decision tree has a good ability to classify the training, but the unknown test data may not have good classification ability, and the generalization ability is weak, that is, there may have been a fitting phenomenon.Pruning and random
training of several classifiers, the tuple that was incorrectly categorized in the previous classifier, is increased in weight so that it is more "concerned" in the classifier that is later established.The final classification is also voted by all classifiers, voting weights depend on the accuracy of the classifierAdaBoost algorithmAdvantages and disadvantages of the lifting algorithmCan get a higher accu
In machine learning, a random forest is composed of many decision trees, because these decision trees adopt a random method, which is also called a random decision tree. There is no association between trees in the random forest.
, indicating that the attribute has a stronger ability to reduce the entropy of the sample, which makes the data more capable of becoming deterministic from uncertainty .1.3 Decision tree over-fittingThe decision tree has a good ability to classify the training, but the unknown test data may not have good classification ability, and the generalization ability is weak, that is, there may have been a fitting phenomenon.Pruning and random
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