The BLAS routines for multiplication and solving linear systems allow for scalar multipliers, usually written alpha and beta, so that the general mutating version of a matrix product is equivalent to
C .= α .* (A * B) + β .* C
I thought I saw 5-argument versions of mul! with a signature like
Are there methods for mul!, etc. that would end up calling LinearAlgebra.BLAS.gemm!with alpha and beta arguments?
The reason I want this is because a calculation in a tight inner loop needs to replace C by C - A*B and I would much prefer to do this in-place. If there are alternative ways to accomplish this I would welcome hearing of them.