I initialized two Mat images as: Mat ft=Mat::zeros(src.rows,src.cols,CV_32FC1),h=Mat::zeros(src.rows,src.cols,CV_32FC1);

and then i have some calculations: ft has fourier transform stored for an image, and h has matrix for Laplacian filtering in fourier domain.......they both have same dimensions,

and then i did multiplication of them using both h*ft and gemm(h,ft,1,NULL,0,temp); function call but while executing it shows some problems..... it reads like this: opencv error assertion failed (some long code and at last says something about gemm in ....matmul.cpp)......termination called after throwing exception of 'cv::exception'