README
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SIMD experiment (Go 1.27+)
This package requires Go 1.27 with GOEXPERIMENT=simd. Unlike simd/archsimd, the
stdlib simd package it is built on is portable: no architecture build tag is required.
See benchmarks.
Platform support
| Architecture | Backing hardware |
|---|---|
| amd64 | AVX / AVX2 / AVX-512, picked at runtime |
| arm64 | NEON |
| wasm | SIMD128 |
| everything else | pure-Go emulation |
On the emulated tier, this package transparently falls back to the equivalent scalar
github.com/samber/lo function instead of paying the emulation overhead.
Controlling the vector width
GODEBUG=simd=<0|128|256|512> forces a specific behaviour for the current process:
GODEBUG=simd=0 go test ./... # force the scalar/lo.* fallback everywhere
GODEBUG=simd=128 go test ./... # force 128-bit vectors
GODEBUG=simd=256 go test ./... # force 256-bit vectors (panics if unsupported by the CPU)
Without GODEBUG=simd, the widest vector the CPU supports (with the required feature set)
is used automatically. Building without GOEXPERIMENT=simd at all compiles this package to
an empty stub with no exported symbols, same as before this package existed.
Running the tests
GOEXPERIMENT=simd go test ./...
Documentation
¶
Overview ¶
Package simd accelerates a subset of the samber/lo slice helpers (Sum, Mean, Min, Max, Clamp, SumBy, MeanBy, Contains) using the Go 1.27 stdlib "simd" package.
Unlike simd/archsimd, the stdlib "simd" package is portable: it maps to AVX/AVX2/AVX512 on amd64, NEON on arm64, SIMD128 on wasm, and falls back to a pure-Go emulation on every other architecture. This package therefore requires no per-architecture build tags.
Building this package requires Go 1.27+ and GOEXPERIMENT=simd. Without the experiment enabled, this file is the only one compiled: the package exposes no symbols.
Fallback ¶
When the current process runs the emulated implementation (no hardware SIMD support, or GODEBUG=simd=0), every helper transparently falls back to the equivalent scalar github.com/samber/lo function, which is faster than paying the emulation overhead.
Source Files