Crate guff_matrix[−][src]

Expand description

Fast SIMD matrix multiplication for finite fields

This crate implements two things:

  1. Fast SIMD-based multiplication of vectors of finite field elements (GF(28) with the polynomial 0x11b)

  2. A (cache-friendly) matrix multiplication routine based on achieving 100% utilisation of the above

This crate supports x86_64 and Arm (v7, v8) with NEON extensions.

The matrix multiplication routine is heavily geared towards use in implementing Reed-Solomon or Information Dispersal Algorithm error-correcting codes.

Building

For x86_64 and Armv8 (Aarch64), building should require no extra options:

cargo build

Optional Features

Currently available options are:

  • simulator — Software simulation of “wrap-around read matrix” (“warm”) multiply
  • arm_dsp — Armv6 (dsp) 4-way SIMD multiply
  • arm_long — Armv7/Armv8 8-way NEON reimplementation of Armv6 code
  • arm_vmull — Armv7/Armv8 8-way NEON vmull/vtbl multiply

To enable building these, use the --features option when building, eg:

RUSTFLAGS="-C target-cpu=native" cargo build --features arm_vmull

Software Simulation Feature

I’ve implemented a pure Rust version of the matrix multiplication code. It uses the same basic idea as the optimised versions, although for clarity, it works a byte at a time instead of simulating SIMD multiplication on 8 or 16 bytes at a time.

Modules

simulator

Non-SIMD, pure Rust simulation of matrix multiplication algorithm

x86

x86_64-specific SIMD

Traits

Simd
SimdMatrix

Functions

_monomorph
gcd
gcd3
gcd4
lcm
lcm3
lcm4
matrix_multiply
simd_warm_multiply⚠