[][src]Crate matrixmultiply

General matrix multiplication for f32, f64 matrices. Operates on matrices with general layout (they can use arbitrary row and column stride).

This crate uses the same macro/microkernel approach to matrix multiplication as the BLIS project.

We presently provide a few good microkernels, portable and for x86-64, and only one operation: the general matrix-matrix multiplication (“gemm”).

Matrix Representation

matrixmultiply supports matrices with general stride, so a matrix is passed using a pointer and four integers:

In this example, A is a m by k matrix. a is a pointer to the element at index 0, 0.

The row stride is the pointer offset (in number of elements) to the element on the next row. It’s the distance from element i, j to i + 1, j.

The column stride is the pointer offset (in number of elements) to the element in the next column. It’s the distance from element i, j to i, j + 1.

For example for a contiguous matrix, row major strides are rsa=k, csa=1 and column major strides are rsa=1, csa=m.

Strides can be negative or even zero, but for a mutable matrix elements may not alias each other.

Portability and Performance

Other Notes

The functions in this crate are thread safe, as long as the destination matrix is distinct.

Functions

dgemm

General matrix multiplication (f64)

sgemm

General matrix multiplication (f32)