Opencv random forest Parameters
[Original source]: http://blog.csdn.net/sangni007/article/details/7488727
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In opencv2.3Inheritance Structure:
API:
Cvrtparams
Defines the extension subclass of the parameter cvdtreeparams for R. T. Training, but does not use all the parameters required by cvdtreeparams (single decision tree. For example, R. T. Usually does not requ
Library (randomforest) data (Iris) Set.seed (indThis article is from the "Nothing-skywalker" blog, please be sure to keep this source http://tianxingzhe.blog.51cto.com/3390077/1657443R language implements random forest code
. The predicted value of a good model should be close to the actual value, which means that most of the points should fall above or near the diagonal line.Prediction based on test setDEXfat_pred Extreme values of predicted valuesXlim Plot (DEXfat_pred ~ DEXfat, data = bodyfat. test, xlab = "Observed ",Ylab = "Predicted", ylim = xlim, xlim = xlim)Abline (a = 0, B = 1)The rendering result is as follows:3. Random ForestWe use the pack
Randomness in random forests is reflected in: 1. Randomness of training data 2. Choosing the randomness of a split propertyCan solve the problem of classification and regression, and all have good estimation performance1. Generating a data description fileMahout describe-p input.csv-f Input.info-d2 I 3 n i 5 n i 3 C L (description file for executing describe generated data)2. Training modelMahout buildforest-d input.csv-ds input.info-sl 5-p-t 5-o fore
Forest In order to prevent overfitting, a random forest is equivalent to several decision trees.Four, KNN nearest neighborSince KNN has to traverse all the remaining points each time it looks for the next closest point to it, the algorithm is expensive.V. Naive BayesTo push the probability that the occurrence of event a occurs under B (where events A and B can
This article introduces the use of random forest random trees in the MLL of opencv Machine Learning Library.
References:
1. breiman,LEO (2001). "random forests ".MachineLearning
2. Random Forests website
If you are not familiar with MLL, refer to this article: opencv Machine
Install.packages ("Randomforest") #安装R包Library (Party) #输入数据Library (randomforest) #引入分析包Output.forest data = readingskills) #创建随机森林Print (output.forest) #查看Print (Importance (Output.forest,type = 2)) #Gini指数The Gini index indicates the purity of the node, and the greater the Gini index, the lower the purity. The average reduction of the Gini value indicates the average reduction of the purity of the variable partition nodes of all trees. For the variable importance measure, the steps are descri
This article mainly implements the stochastic forest algorithm in the Pyspark environment:
%pyspark from Pyspark.ml.linalg import Vectors to pyspark.ml.feature import stringindexer from Pyspark.ml.classificati On the import randomforestclassifier from pyspark.sql import Row #任务目标: Solve two classification problems through random forests and evaluate #1 of classification effects. Read data = Spark.sql (""
that is divided when selecting the optimal attribute cannot exceed this value.
When an integer, the maximum number of features, or the number of features of the training set when it is a decimal;
If "Auto", then Max_features=sqrt (n_features).
If "sqrt", Thenmax_features=sqrt (N_features).
If "Log2", Thenmax_features=log2 (N_features).
If None, then max_features=n_features.
max_depth: (default=none) sets the maximum depth of the tree, the default is None, so that when making a contribution, eac
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