Method eigen

deps/opencv/modules/core/src/lapack.cpp:1466–1494

/////////////////// finding eigenvalues and eigenvectors of a symmetric matrix ///////////////

bool cv::eigen( InputArray _src, bool computeEvects, OutputArray _evals, OutputArray _evects )
{
    Mat src = _src.getMat();
    int type = src.type();
    int n = src.rows;

    CV_Assert( src.rows == src.cols );
    CV_Assert (type == CV_32F || type == CV_64F);

    Mat v;
    if( computeEvects )
    {
        _evects.create(n, n, type);
        v = _evects.getMat();
    }

    size_t elemSize = src.elemSize(), astep = alignSize(n*elemSize, 16);
    AutoBuffer<uchar> buf(n*astep + n*5*elemSize + 32);
    uchar* ptr = alignPtr((uchar*)buf, 16);
    Mat a(n, n, type, ptr, astep), w(n, 1, type, ptr + astep*n);
    ptr += astep*n + elemSize*n;
    src.copyTo(a);
    bool ok = type == CV_32F ?
        Jacobi(a.ptr<float>(), a.step, w.ptr<float>(), v.ptr<float>(), v.step, n, ptr) :
        Jacobi(a.ptr<double>(), a.step, w.ptr<double>(), v.ptr<double>(), v.step, n, ptr);

    w.copyTo(_evals);
    return ok;
}

bool cv::eigen( InputArray src, OutputArray evals, int, int )
{