/////////////////////////////////////////////////////////////////////////////////////// // IMPORTANT: READ BEFORE DOWNLOADING, COPYING, INSTALLING OR USING. // By downloading, copying, installing or using the software you agree to this license. // If you do not agree to this license, do not download, install, // copy or use the software. // This is a implementation of the Logistic Regression algorithm in C++ in OpenCV. // AUTHOR: // Rahul Kavi rahulkavi[at]live[at]com // # You are free to use, change, or redistribute the code in any way you wish for // # non-commercial purposes, but please maintain the name of the original author. // # This code comes with no warranty of any kind. // # // # You are free to use, change, or redistribute the code in any way you wish for // # non-commercial purposes, but please maintain the name of the original author. // # This code comes with no warranty of any kind. // # Logistic Regression ALGORITHM // License Agreement // For Open Source Computer Vision Library // Copyright (C) 2000-2008, Intel Corporation, all rights reserved. // Copyright (C) 2008-2011, Willow Garage Inc., all rights reserved. // Third party copyrights are property of their respective owners. // Redistribution and use in source and binary forms, with or without modification, // are permitted provided that the following conditions are met: // * Redistributions of source code must retain the above copyright notice, // this list of conditions and the following disclaimer. // * Redistributions in binary form must reproduce the above copyright notice, // this list of conditions and the following disclaimer in the documentation // and/or other materials provided with the distribution. // * The name of the copyright holders may not be used to endorse or promote products // derived from this software without specific prior written permission. // This software is provided by the copyright holders and contributors "as is" and // any express or implied warranties, including, but not limited to, the implied // warranties of merchantability and fitness for a particular purpose are disclaimed. // In no event shall the Intel Corporation or contributors be liable for any direct, // indirect, incidental, special, exemplary, or consequential damages // (including, but not limited to, procurement of substitute goods or services; // loss of use, data, or profits; or business interruption) however caused // and on any theory of liability, whether in contract, strict liability, // or tort (including negligence or otherwise) arising in any way out of // the use of this software, even if advised of the possibility of such damage. #include "precomp.hpp" using namespace std; namespace cv { namespace ml { class LrParams { public: LrParams() { alpha = 0.001; num_iters = 1000; norm = LogisticRegression::REG_L2; train_method = LogisticRegression::BATCH; mini_batch_size = 1; term_crit = TermCriteria(TermCriteria::COUNT + TermCriteria::EPS, num_iters, alpha); } double alpha; //!< learning rate. int num_iters; //!< number of iterations. int norm; int train_method; int mini_batch_size; TermCriteria term_crit; }; class LogisticRegressionImpl : public LogisticRegression { public: LogisticRegressionImpl() { } virtual ~LogisticRegressionImpl() {} CV_IMPL_PROPERTY(double, LearningRate, params.alpha) CV_IMPL_PROPERTY(int, Iterations, params.num_iters) CV_IMPL_PROPERTY(int, Regularization, params.norm) CV_IMPL_PROPERTY(int, TrainMethod, params.train_method) CV_IMPL_PROPERTY(int, MiniBatchSize, params.mini_batch_size) CV_IMPL_PROPERTY(TermCriteria, TermCriteria, params.term_crit) virtual bool train( const Ptr& trainData, int=0 ); virtual float predict(InputArray samples, OutputArray results, int) const; virtual void clear(); virtual void write(FileStorage& fs) const; virtual void read(const FileNode& fn); virtual Mat get_learnt_thetas() const; virtual int getVarCount() const { return learnt_thetas.cols; } virtual bool isTrained() const { return !learnt_thetas.empty(); } virtual bool isClassifier() const { return true; } virtual String getDefaultName() const { return "opencv_ml_lr"; } protected: Mat calc_sigmoid(const Mat& data) const; double compute_cost(const Mat& _data, const Mat& _labels, const Mat& _init_theta); void compute_gradient(const Mat& _data, const Mat& _labels, const Mat &_theta, const double _lambda, Mat & _gradient ); Mat batch_gradient_descent(const Mat& _data, const Mat& _labels, const Mat& _init_theta); Mat mini_batch_gradient_descent(const Mat& _data, const Mat& _labels, const Mat& _init_theta); bool set_label_map(const Mat& _labels_i); Mat remap_labels(const Mat& _labels_i, const map& lmap) const; protected: LrParams params; Mat learnt_thetas; map forward_mapper; map reverse_mapper; Mat labels_o; Mat labels_n; }; Ptr LogisticRegression::create() { return makePtr(); } bool LogisticRegressionImpl::train(const Ptr& trainData, int) { clear(); Mat _data_i = trainData->getSamples(); Mat _labels_i = trainData->getResponses(); CV_Assert( !_labels_i.empty() && !_data_i.empty()); // check the number of columns if(_labels_i.cols != 1) { CV_Error( CV_StsBadArg, "_labels_i should be a column matrix" ); } // check data type. // data should be of floating type CV_32FC1 if((_data_i.type() != CV_32FC1) || (_labels_i.type() != CV_32FC1)) { CV_Error( CV_StsBadArg, "data and labels must be a floating point matrix" ); } bool ok = false; Mat labels; set_label_map(_labels_i); int num_classes = (int) this->forward_mapper.size(); // add a column of ones Mat data_t; hconcat( cv::Mat::ones( _data_i.rows, 1, CV_32F ), _data_i, data_t ); if(num_classes < 2) { CV_Error( CV_StsBadArg, "data should have atleast 2 classes" ); } if(_labels_i.rows != _data_i.rows) { CV_Error( CV_StsBadArg, "number of rows in data and labels should be the equal" ); } Mat thetas = Mat::zeros(num_classes, data_t.cols, CV_32F); Mat init_theta = Mat::zeros(data_t.cols, 1, CV_32F); Mat labels_l = remap_labels(_labels_i, this->forward_mapper); Mat new_local_labels; int ii=0; Mat new_theta; if(num_classes == 2) { labels_l.convertTo(labels, CV_32F); if(this->params.train_method == LogisticRegression::BATCH) new_theta = batch_gradient_descent(data_t, labels, init_theta); else new_theta = mini_batch_gradient_descent(data_t, labels, init_theta); thetas = new_theta.t(); } else { /* take each class and rename classes you will get a theta per class as in multi class class scenario, we will have n thetas for n classes */ ii = 0; for(map::iterator it = this->forward_mapper.begin(); it != this->forward_mapper.end(); ++it) { new_local_labels = (labels_l == it->second)/255; new_local_labels.convertTo(labels, CV_32F); if(this->params.train_method == LogisticRegression::BATCH) new_theta = batch_gradient_descent(data_t, labels, init_theta); else new_theta = mini_batch_gradient_descent(data_t, labels, init_theta); hconcat(new_theta.t(), thetas.row(ii)); ii += 1; } } this->learnt_thetas = thetas.clone(); if( cvIsNaN( (double)sum(this->learnt_thetas)[0] ) ) { CV_Error( CV_StsBadArg, "check training parameters. Invalid training classifier" ); } ok = true; return ok; } float LogisticRegressionImpl::predict(InputArray samples, OutputArray results, int flags) const { /* returns a class of the predicted class class names can be 1,2,3,4, .... etc */ Mat thetas, data, pred_labs; data = samples.getMat(); const bool rawout = flags & StatModel::RAW_OUTPUT; // check if learnt_mats array is populated if(this->learnt_thetas.total()<=0) { CV_Error( CV_StsBadArg, "classifier should be trained first" ); } if(data.type() != CV_32F) { CV_Error( CV_StsBadArg, "data must be of floating type" ); } // add a column of ones Mat data_t; hconcat( cv::Mat::ones( data.rows, 1, CV_32F ), data, data_t ); if ( learnt_thetas.type() == CV_32F ) { thetas = learnt_thetas; } else { this->learnt_thetas.convertTo( thetas, CV_32F ); } CV_Assert(thetas.rows > 0); double min_val; double max_val; Point min_loc; Point max_loc; Mat labels; Mat labels_c; Mat temp_pred; Mat pred_m = Mat::zeros(data_t.rows, thetas.rows, data.type()); if(thetas.rows == 1) { temp_pred = calc_sigmoid(data_t*thetas.t()); CV_Assert(temp_pred.cols==1); pred_m = temp_pred.clone(); // if greater than 0.5, predict class 0 or predict class 1 temp_pred = (temp_pred>0.5)/255; temp_pred.convertTo(labels_c, CV_32S); } else { for(int i = 0;ireverse_mapper); // convert pred_labs to integer type pred_labs.convertTo(pred_labs, CV_32S); // return either the labels or the raw output if ( results.needed() ) { if ( rawout ) { pred_m.copyTo( results ); } else { pred_labs.copyTo(results); } } return ( pred_labs.empty() ? 0.f : (float) pred_labs.at< int >( 0 ) ); } Mat LogisticRegressionImpl::calc_sigmoid(const Mat& data) const { Mat dest; exp(-data, dest); return 1.0/(1.0+dest); } double LogisticRegressionImpl::compute_cost(const Mat& _data, const Mat& _labels, const Mat& _init_theta) { int llambda = 0; int m; int n; double cost = 0; double rparameter = 0; Mat theta_b; Mat theta_c; Mat d_a; Mat d_b; m = _data.rows; n = _data.cols; theta_b = _init_theta(Range(1, n), Range::all()); if (params.norm != REG_DISABLE) { llambda = 1; } if(this->params.norm == LogisticRegression::REG_L1) { rparameter = (llambda/(2*m)) * sum(theta_b)[0]; } else { // assuming it to be L2 by default multiply(theta_b, theta_b, theta_c, 1); rparameter = (llambda/(2*m)) * sum(theta_c)[0]; } d_a = calc_sigmoid(_data * _init_theta); log(d_a, d_a); multiply(d_a, _labels, d_a); // use the fact that: log(1 - sigmoid(x)) = log(sigmoid(-x)) d_b = calc_sigmoid(- _data * _init_theta); log(d_b, d_b); multiply(d_b, 1-_labels, d_b); cost = (-1.0/m) * (sum(d_a)[0] + sum(d_b)[0]); cost = cost + rparameter; if(cvIsNaN( cost ) == 1) { CV_Error( CV_StsBadArg, "check training parameters. Invalid training classifier" ); } return cost; } void LogisticRegressionImpl::compute_gradient(const Mat& _data, const Mat& _labels, const Mat &_theta, const double _lambda, Mat & _gradient ) { const int m = _data.rows; Mat pcal_a, pcal_b, pcal_ab; const Mat z = _data * _theta; CV_Assert( _gradient.rows == _theta.rows && _gradient.cols == _theta.cols ); pcal_a = calc_sigmoid(z) - _labels; pcal_b = _data(Range::all(), Range(0,1)); multiply(pcal_a, pcal_b, pcal_ab, 1); _gradient.row(0) = ((float)1/m) * sum(pcal_ab)[0]; //cout<<"for each training data entry"<params.alpha<=0) { CV_Error( CV_StsBadArg, "check training parameters (learning rate) for the classifier" ); } if(this->params.num_iters <= 0) { CV_Error( CV_StsBadArg, "number of iterations cannot be zero or a negative number" ); } int llambda = 0; int m; Mat theta_p = _init_theta.clone(); Mat gradient( theta_p.rows, theta_p.cols, theta_p.type() ); m = _data.rows; if (params.norm != REG_DISABLE) { llambda = 1; } for(int i = 0;iparams.num_iters;i++) { // this seems to only be called to ensure that cost is not NaN compute_cost(_data, _labels, theta_p); compute_gradient( _data, _labels, theta_p, llambda, gradient ); theta_p = theta_p - ( static_cast(this->params.alpha)/m)*gradient; } return theta_p; } Mat LogisticRegressionImpl::mini_batch_gradient_descent(const Mat& _data, const Mat& _labels, const Mat& _init_theta) { // implements batch gradient descent int lambda_l = 0; int m; int j = 0; int size_b = this->params.mini_batch_size; if(this->params.mini_batch_size <= 0 || this->params.alpha == 0) { CV_Error( CV_StsBadArg, "check training parameters for the classifier" ); } if(this->params.num_iters <= 0) { CV_Error( CV_StsBadArg, "number of iterations cannot be zero or a negative number" ); } Mat theta_p = _init_theta.clone(); Mat gradient( theta_p.rows, theta_p.cols, theta_p.type() ); Mat data_d; Mat labels_l; if (params.norm != REG_DISABLE) { lambda_l = 1; } for(int i = 0;iparams.term_crit.maxCount;i++) { if(j+size_b<=_data.rows) { data_d = _data(Range(j,j+size_b), Range::all()); labels_l = _labels(Range(j,j+size_b),Range::all()); } else { data_d = _data(Range(j, _data.rows), Range::all()); labels_l = _labels(Range(j, _labels.rows),Range::all()); } m = data_d.rows; // this seems to only be called to ensure that cost is not NaN compute_cost(data_d, labels_l, theta_p); compute_gradient(data_d, labels_l, theta_p, lambda_l, gradient); theta_p = theta_p - ( static_cast(this->params.alpha)/m)*gradient; j += this->params.mini_batch_size; // if parsed through all data variables if (j >= _data.rows) { j = 0; } } return theta_p; } bool LogisticRegressionImpl::set_label_map(const Mat &_labels_i) { // this function creates two maps to map user defined labels to program friendly labels two ways. int ii = 0; Mat labels; this->labels_o = Mat(0,1, CV_8U); this->labels_n = Mat(0,1, CV_8U); _labels_i.convertTo(labels, CV_32S); for(int i = 0;iforward_mapper[labels.at(i)] += 1; } for(map::iterator it = this->forward_mapper.begin(); it != this->forward_mapper.end(); ++it) { this->forward_mapper[it->first] = ii; this->labels_o.push_back(it->first); this->labels_n.push_back(ii); ii += 1; } for(map::iterator it = this->forward_mapper.begin(); it != this->forward_mapper.end(); ++it) { this->reverse_mapper[it->second] = it->first; } return true; } Mat LogisticRegressionImpl::remap_labels(const Mat& _labels_i, const map& lmap) const { Mat labels; _labels_i.convertTo(labels, CV_32S); Mat new_labels = Mat::zeros(labels.rows, labels.cols, labels.type()); CV_Assert( !lmap.empty() ); for(int i =0;i(i,0) = lmap.find(labels.at(i,0))->second; } return new_labels; } void LogisticRegressionImpl::clear() { this->learnt_thetas.release(); this->labels_o.release(); this->labels_n.release(); } void LogisticRegressionImpl::write(FileStorage& fs) const { // check if open if(fs.isOpened() == 0) { CV_Error(CV_StsBadArg,"file can't open. Check file path"); } string desc = "Logisitic Regression Classifier"; fs<<"classifier"<params.alpha; fs<<"iterations"<params.num_iters; fs<<"norm"<params.norm; fs<<"train_method"<params.train_method; if(this->params.train_method == LogisticRegression::MINI_BATCH) { fs<<"mini_batch_size"<params.mini_batch_size; } fs<<"learnt_thetas"<learnt_thetas; fs<<"n_labels"<labels_n; fs<<"o_labels"<labels_o; } void LogisticRegressionImpl::read(const FileNode& fn) { // check if empty if(fn.empty()) { CV_Error( CV_StsBadArg, "empty FileNode object" ); } this->params.alpha = (double)fn["alpha"]; this->params.num_iters = (int)fn["iterations"]; this->params.norm = (int)fn["norm"]; this->params.train_method = (int)fn["train_method"]; if(this->params.train_method == LogisticRegression::MINI_BATCH) { this->params.mini_batch_size = (int)fn["mini_batch_size"]; } fn["learnt_thetas"] >> this->learnt_thetas; fn["o_labels"] >> this->labels_o; fn["n_labels"] >> this->labels_n; for(int ii =0;iiforward_mapper[labels_o.at(ii,0)] = labels_n.at(ii,0); this->reverse_mapper[labels_n.at(ii,0)] = labels_o.at(ii,0); } } Mat LogisticRegressionImpl::get_learnt_thetas() const { return this->learnt_thetas; } } } /* End of file. */