.TH "mlpack::naive_bayes::NaiveBayesClassifier< MatType >" 3 "Tue Sep 9 2014" "Version 1.0.10" "MLPACK" \" -*- nroff -*-
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.SH NAME
mlpack::naive_bayes::NaiveBayesClassifier< MatType > \- 
.PP
The simple Naive Bayes classifier\&.  

.SH SYNOPSIS
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.PP
.SS "Public Member Functions"

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.RI "\fBNaiveBayesClassifier\fP (const MatType &data, const arma::Col< size_t > &labels, const size_t classes, const bool incrementalVariance=false)"
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.RI "\fIInitializes the classifier as per the input and then trains it by calculating the sample mean and variances\&. \fP"
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.RI "void \fBClassify\fP (const MatType &data, arma::Col< size_t > &results)"
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.RI "\fIGiven a bunch of data points, this function evaluates the class of each of those data points, and puts it in the vector 'results'\&. \fP"
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.RI "const MatType & \fBMeans\fP () const "
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.RI "\fIGet the sample means for each class\&. \fP"
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.RI "MatType & \fBMeans\fP ()"
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.RI "\fIModify the sample means for each class\&. \fP"
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.RI "const arma::vec & \fBProbabilities\fP () const "
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.RI "\fIGet the prior probabilities for each class\&. \fP"
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.RI "arma::vec & \fBProbabilities\fP ()"
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.RI "\fIModify the prior probabilities for each class\&. \fP"
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.RI "const MatType & \fBVariances\fP () const "
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.RI "\fIGet the sample variances for each class\&. \fP"
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.RI "MatType & \fBVariances\fP ()"
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.RI "\fIModify the sample variances for each class\&. \fP"
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.SS "Private Attributes"

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.RI "MatType \fBmeans\fP"
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.RI "\fISample mean for each class\&. \fP"
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.RI "arma::vec \fBprobabilities\fP"
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.RI "\fIClass probabilities\&. \fP"
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.RI "MatType \fBvariances\fP"
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.RI "\fISample variances for each class\&. \fP"
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.SH "Detailed Description"
.PP 

.SS "template<typename MatType = arma::mat>class mlpack::naive_bayes::NaiveBayesClassifier< MatType >"
The simple Naive Bayes classifier\&. 

This class trains on the data by calculating the sample mean and variance of the features with respect to each of the labels, and also the class probabilities\&. The class labels are assumed to be positive integers (starting with 0), and are expected to be the last row of the data input to the constructor\&.
.PP
Mathematically, it computes P(X_i = x_i | Y = y_j) for each feature X_i for each of the labels y_j\&. Alongwith this, it also computes the classs probabilities P(Y = y_j)\&.
.PP
For classifying a data point (x_1, x_2, \&.\&.\&., x_n), it computes the following: arg max_y(P(Y = y)*P(X_1 = x_1 | Y = y) * \&.\&.\&. * P(X_n = x_n | Y = y))
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Example use:
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.PP
.nf
extern arma::mat training_data, testing_data;
NaiveBayesClassifier<> nbc(training_data, 5);
arma::vec results;

nbc\&.Classify(testing_data, results);
.fi
.PP
 
.PP
Definition at line 58 of file naive_bayes_classifier\&.hpp\&.
.SH "Constructor & Destructor Documentation"
.PP 
.SS "template<typename MatType  = arma::mat> \fBmlpack::naive_bayes::NaiveBayesClassifier\fP< MatType >::\fBNaiveBayesClassifier\fP (const MatType &data, const arma::Col< size_t > &labels, const size_tclasses, const boolincrementalVariance = \fCfalse\fP)"

.PP
Initializes the classifier as per the input and then trains it by calculating the sample mean and variances\&. The input data is expected to have integer labels as the last row (starting with 0 and not greater than the number of classes)\&.
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Example use: 
.PP
.nf
extern arma::mat training_data, testing_data;
extern arma::Col<size_t> labels;
NaiveBayesClassifier nbc(training_data, labels, 5);

.fi
.PP
.PP
\fBParameters:\fP
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\fIdata\fP Training data points\&. 
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\fIlabels\fP Labels corresponding to training data points\&. 
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\fIclasses\fP Number of classes in this classifier\&. 
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\fIincrementalVariance\fP If true, an incremental algorithm is used to calculate the variance; this can prevent loss of precision in some cases, but will be somewhat slower to calculate\&. 
.RE
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.SH "Member Function Documentation"
.PP 
.SS "template<typename MatType  = arma::mat> void \fBmlpack::naive_bayes::NaiveBayesClassifier\fP< MatType >::Classify (const MatType &data, arma::Col< size_t > &results)"

.PP
Given a bunch of data points, this function evaluates the class of each of those data points, and puts it in the vector 'results'\&. 
.PP
.nf
arma::mat test_data; // each column is a test point
arma::Col<size_t> results;
\&.\&.\&.
nbc\&.Classify(test_data, &results);

.fi
.PP
.PP
\fBParameters:\fP
.RS 4
\fIdata\fP List of data points\&. 
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\fIresults\fP Vector that class predictions will be placed into\&. 
.RE
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.SS "template<typename MatType  = arma::mat> const MatType& \fBmlpack::naive_bayes::NaiveBayesClassifier\fP< MatType >::Means () const\fC [inline]\fP"

.PP
Get the sample means for each class\&. 
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Definition at line 113 of file naive_bayes_classifier\&.hpp\&.
.PP
References mlpack::naive_bayes::NaiveBayesClassifier< MatType >::means\&.
.SS "template<typename MatType  = arma::mat> MatType& \fBmlpack::naive_bayes::NaiveBayesClassifier\fP< MatType >::Means ()\fC [inline]\fP"

.PP
Modify the sample means for each class\&. 
.PP
Definition at line 115 of file naive_bayes_classifier\&.hpp\&.
.PP
References mlpack::naive_bayes::NaiveBayesClassifier< MatType >::means\&.
.SS "template<typename MatType  = arma::mat> const arma::vec& \fBmlpack::naive_bayes::NaiveBayesClassifier\fP< MatType >::Probabilities () const\fC [inline]\fP"

.PP
Get the prior probabilities for each class\&. 
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Definition at line 123 of file naive_bayes_classifier\&.hpp\&.
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References mlpack::naive_bayes::NaiveBayesClassifier< MatType >::probabilities\&.
.SS "template<typename MatType  = arma::mat> arma::vec& \fBmlpack::naive_bayes::NaiveBayesClassifier\fP< MatType >::Probabilities ()\fC [inline]\fP"

.PP
Modify the prior probabilities for each class\&. 
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Definition at line 125 of file naive_bayes_classifier\&.hpp\&.
.PP
References mlpack::naive_bayes::NaiveBayesClassifier< MatType >::probabilities\&.
.SS "template<typename MatType  = arma::mat> const MatType& \fBmlpack::naive_bayes::NaiveBayesClassifier\fP< MatType >::Variances () const\fC [inline]\fP"

.PP
Get the sample variances for each class\&. 
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Definition at line 118 of file naive_bayes_classifier\&.hpp\&.
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References mlpack::naive_bayes::NaiveBayesClassifier< MatType >::variances\&.
.SS "template<typename MatType  = arma::mat> MatType& \fBmlpack::naive_bayes::NaiveBayesClassifier\fP< MatType >::Variances ()\fC [inline]\fP"

.PP
Modify the sample variances for each class\&. 
.PP
Definition at line 120 of file naive_bayes_classifier\&.hpp\&.
.PP
References mlpack::naive_bayes::NaiveBayesClassifier< MatType >::variances\&.
.SH "Member Data Documentation"
.PP 
.SS "template<typename MatType  = arma::mat> MatType \fBmlpack::naive_bayes::NaiveBayesClassifier\fP< MatType >::means\fC [private]\fP"

.PP
Sample mean for each class\&. 
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Definition at line 62 of file naive_bayes_classifier\&.hpp\&.
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Referenced by mlpack::naive_bayes::NaiveBayesClassifier< MatType >::Means()\&.
.SS "template<typename MatType  = arma::mat> arma::vec \fBmlpack::naive_bayes::NaiveBayesClassifier\fP< MatType >::probabilities\fC [private]\fP"

.PP
Class probabilities\&. 
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Definition at line 68 of file naive_bayes_classifier\&.hpp\&.
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Referenced by mlpack::naive_bayes::NaiveBayesClassifier< MatType >::Probabilities()\&.
.SS "template<typename MatType  = arma::mat> MatType \fBmlpack::naive_bayes::NaiveBayesClassifier\fP< MatType >::variances\fC [private]\fP"

.PP
Sample variances for each class\&. 
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Definition at line 65 of file naive_bayes_classifier\&.hpp\&.
.PP
Referenced by mlpack::naive_bayes::NaiveBayesClassifier< MatType >::Variances()\&.

.SH "Author"
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