Finding Rank of Kernel/Matrix using OpenCV

Basically I want to find the rank of a given kernel/matrix so that I can check whether it is separable or not? Is there a function in OpenCV to find the rank of a kernel? If I'm correct, we can use the compute method of svd class to find the singular values, but after that how do we calculate the rank? The below is the code I used. double k = 3; float kdata[] = {2,0,2,0,1,0,0,0,0}; Mat kernel(k,k,CV_32F, kdata); Mat s,u,v; SVD::compute(kernel,s,u,v);