sepia_img = img.dot(sepia_matrix.T) Since sepia matrix rows do not have unit sums, once the full sepia image is constructed, we need to rescale the result. sepia_img /= sepia_img.max() then extend ...

And in most cases, these libraries ultimately call an optimized version of the Basic Linear Algebra Subroutine (BLAS) library DGEMM (Double-precision GEneral Matrix Multiplication). Developers have ...