NICE_VisLearning/features/simplefeatures/matlab/HelperDataConversionMex.h

#ifndef HELPERDATACONVERSIONMEX_H
#define HELPERDATACONVERSIONMEX_H

// STL includes
#include <math.h>
#include <matrix.h>
#include <mex.h>

// NICE-core includes
#include <core/vector/MatrixT.h>
#include <core/vector/VectorT.h>

// Interface for conversion between Matlab and C objects
#include "gp-hik-core/matlab/ConverterMatlabToNICE.h"
#include "gp-hik-core/matlab/ConverterNICEToMatlab.h"

#include "vislearning/cbaselib/Example.h"

namespace NICE {

namespace MatlabConversion {

/**
 * @brief Create an Examples class from a given full matrix of features and a matrix/vector of labels.
 *
 * The Examples object consists of individual Example objects containing the label and a pointer to the provided raw feature data.
 * Note: No feature data is copied - an Example only contains a pointer to the raw double data.
 * An NICE::Vector is created as an wrapper around this raw double pointer using it, but not copying it.
 * You need to take care to delete these wrapper vectors once you're finished working with the Examples object, otherwise you generate a memory leak.
 *
 * @param p_pArrTrainData double MATLAB matrix containing the features (dimension M) of N samples ( M x N matrix )
 * @param p_pArrTrainLabels double MATLAB matrix containing the labels for N samples (1xN)
 *
 * @param p_ExamplesTrain created Examples class (vector of N Example object with each Example containing a valid vec-ptr to the feature data [uncopied] )
 *
 * @return true for successful Examples creation
 * @author Johannes Ruehle
 */
bool convertDoubleRawPointersToExamples( const mxArray *p_pArrTrainData, const mxArray *p_pArrTrainLabels, OBJREC::Examples &p_ExamplesTrain )
{

    int iNumFeatureDimension = mxGetM( p_pArrTrainData ); // feature dimensions

    NICE::Vector yValuesTrain = convertDoubleVectorToNice( p_pArrTrainLabels );
    NICE::Matrix matDataTrain = convertDoubleMatrixToNice( p_pArrTrainData   );
    assert( yValuesTrain.size() == matDataTrain.cols() );
    assert( iNumFeatureDimension == matDataTrain.rows() );

    p_ExamplesTrain.reserve( matDataTrain.cols() );

    const double *pDataPtr = matDataTrain.getDataPointer();

    for (int i = 0; i < (int)matDataTrain.cols(); i++, pDataPtr+= iNumFeatureDimension )
    {
        NICE::Vector *t_pVecTrainData = new NICE::Vector( pDataPtr , (size_t)iNumFeatureDimension);
        OBJREC::Example t_Example;
        t_Example.vec = t_pVecTrainData;

        p_ExamplesTrain.push_back( std::pair<int, OBJREC::Example>( (int)yValuesTrain[i], t_Example ) );
    }

    return true;
}

}

}

#endif //HELPERDATACONVERSIONMEX_H