🐙 Poulpy-CPU-AVX

Poulpy-CPU-AVX is a Rust crate that provides an AVX2 + FMA accelerated CPU backend for Poulpy.

This backend implements the Poulpy HAL extension traits and can be used by:

• poulpy-hal
• poulpy-core
• poulpy-schemes

🚩 Safety and Requirements

To avoid illegal hardware instructions (SIGILL) on unsupported CPUs, this backend is opt-in and only builds when explicitly requested.

If enable-avx is enabled but the target does not provide these capabilities, the build fails immediately with a clear error message, rather than generating invalid binaries.

When enable-avx is not enabled, this crate is simply skipped and Poulpy automatically falls back to the portable poulpy-cpu-ref backend. This ensure that Poulpy's workspace remains portable (e.g. for macOS ARM).

⚙️ Building with the AVX backend enabled

Because the compiler must generate AVX2 + FMA instructions, both the Cargo feature and CPU target flags must be specified:

RUSTFLAGS="-C target-feature=+avx2,+fma" \
cargo build --features enable-avx

Running an example

RUSTFLAGS="-C target-feature=+avx2,+fma" \
cargo run --example <name> --features enable-avx

Running benchmarks

RUSTFLAGS="-C target-feature=+avx2,+fma" \
cargo bench --features enable-avx

Basic Usage

This crate exposes two AVX2-accelerated backends:

use poulpy_cpu_avx::{FFT64Avx, NTT120Avx};
use poulpy_hal::{api::ModuleNew, layouts::Module};

let log_n: usize = 10;

// f64 FFT backend (AVX2 + FMA)
let module: Module<FFT64Avx> = Module::<FFT64Avx>::new(1 << log_n);

// Q120 NTT backend (AVX2, CRT over four ~30-bit primes)
let module: Module<NTT120Avx> = Module::<NTT120Avx>::new(1 << log_n);

Once compiled with enable-avx, both backends are usable transparently anywhere Poulpy expects a backend type (poulpy-hal, poulpy-core, poulpy-schemes).

🤝 Contributors

To implement your own Poulpy backend (SIMD or accelerator):

1. Define a backend struct
2. Implement the open extension traits from poulpy-hal/oep
3. Implement the Backend trait

Your backend will automatically integrate with:

• poulpy-hal
• poulpy-core
• poulpy-schemes

No modifications to those crates are required — the HAL provides the extension points.

For questions or guidance, feel free to open an issue or discussion in the repository.