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//     Jin Ma, jin@multicorewareinc.com
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#include "precomp.hpp"

using namespace cv;
using namespace cv::ocl;

KalmanFilter::KalmanFilter()
{

}

KalmanFilter::KalmanFilter(int dynamParams, int measureParams, int controlParams, int type)
{
    init(dynamParams, measureParams, controlParams, type);
}

void KalmanFilter::init(int DP, int MP, int CP, int type)
{
    CV_Assert( DP > 0 && MP > 0 );
    CV_Assert( type == CV_32F || type == CV_64F );
    CP = cv::max(CP, 0);

    statePre.create(DP, 1, type);
    statePre.setTo(Scalar::all(0));

    statePost.create(DP, 1, type);
    statePost.setTo(Scalar::all(0));

    transitionMatrix.create(DP, DP, type);
    setIdentity(transitionMatrix, 1);

    processNoiseCov.create(DP, DP, type);
    setIdentity(processNoiseCov, 1);

    measurementNoiseCov.create(MP, MP, type);
    setIdentity(measurementNoiseCov, 1);

    measurementMatrix.create(MP, DP, type);
    measurementMatrix.setTo(Scalar::all(0));

    errorCovPre.create(DP, DP, type);
    errorCovPre.setTo(Scalar::all(0));

    errorCovPost.create(DP, DP, type);
    errorCovPost.setTo(Scalar::all(0));

    gain.create(DP, MP, type);
    gain.setTo(Scalar::all(0));

    if( CP > 0 )
    {
        controlMatrix.create(DP, CP, type);
        controlMatrix.setTo(Scalar::all(0));
    }
    else
        controlMatrix.release();

    temp1.create(DP, DP, type);
    temp2.create(MP, DP, type);
    temp3.create(MP, MP, type);
    temp4.create(MP, DP, type);
    temp5.create(MP, 1, type);
}

CV_EXPORTS const oclMat& KalmanFilter::predict(const oclMat& control)
{
    gemm(transitionMatrix, statePost, 1, oclMat(), 0, statePre);
    oclMat temp;

    if(control.data)
        gemm(controlMatrix, control, 1, statePre, 1, statePre);
    gemm(transitionMatrix, errorCovPost, 1, oclMat(), 0, temp1);
    gemm(temp1, transitionMatrix, 1, processNoiseCov, 1, errorCovPre, GEMM_2_T);
    statePre.copyTo(statePost);
    return statePre;
}

CV_EXPORTS const oclMat& KalmanFilter::correct(const oclMat& measurement)
{
    CV_Assert(measurement.empty() == false);
    gemm(measurementMatrix, errorCovPre, 1, oclMat(), 0, temp2);
    gemm(temp2, measurementMatrix, 1, measurementNoiseCov, 1, temp3, GEMM_2_T);
    Mat temp;
    solve(Mat(temp3), Mat(temp2), temp, DECOMP_SVD);
    temp4.upload(temp);
    gain = temp4.t();
    gemm(measurementMatrix, statePre, -1, measurement, 1, temp5);
    gemm(gain, temp5, 1, statePre, 1, statePost);
    gemm(gain, temp2, -1, errorCovPre, 1, errorCovPost);
    return statePost;
}