Variants of matrix-matrix multiplication for Fortran-90

Abstract

The Fortran-90 standard requires an intrinsic function matmul which multiplies two matrices together to produce a third as the result. However, the standard does not specify which algorithm to use. We consider an extension to the matmul syntax which allows a Winograd variant of Strassen's algorithm to be added. We discuss an implementation that is in a commercial Fortran-90 offering.