cuda library for calculate diagonal of a matrix

Question

I want to multiply 2 matrices together. And I only want the diagonal of the result matrix, so I don't want to calculate other elements. I am wondering if there is a function implemented in some existing library, such as cublas or other c++ library.

I know I can do that through a kernel wrapper, and cuda kernel for this is doable. But I want to check if there is library function available first. Thanks.