strided-perm

Cache-efficient tensor permutation / transpose, inspired by HPTT (Springer et al., 2017).

Usage

Copy from any strided-view source view into a mutable destination view with the same shape:

use strided_perm::copy_into;
use strided_view::StridedArray;

let src = StridedArray::<f64>::from_fn_col_major(&[2, 3], |idx| {
    (idx[0] + 10 * idx[1]) as f64
});
let transposed = src.view().permute(&[1, 0]).unwrap();

let mut dst = StridedArray::<f64>::col_major(transposed.dims());
copy_into(&mut dst.view_mut(), &transposed).unwrap();

Use copy_into_col_major when the destination is known to be column-major and you want to make that layout contract explicit.

copy_into_uninit (and copy_into_uninit_par) takes a StridedViewMut<MaybeUninit<T>> destination over fresh storage. It runs the same engine, selected on T rather than on MaybeUninit<T>, so the native f32/f64 kernels still apply; every element the views describe is written exactly once, through raw pointers only.

Parallel Feature

Enable the parallel feature to use Rayon-backed copy entry points:

[dependencies]
strided-perm = { version = "0.4", features = ["parallel"] }

# use strided_perm::copy_into_par;
# use strided_view::StridedArray;
# let src = StridedArray::<f64>::col_major(&[2, 3]);
# let mut dst = StridedArray::<f64>::col_major(&[2, 3]);
copy_into_par(&mut dst.view_mut(), &src.view()).unwrap();

Benchmarks live in strided-rs-benchmark-suite.

Acknowledgments and License

The transpose engine in src/hptt/ reimplements the algorithm of HPTT by Paul Springer, Tong Su, and Paolo Bientinesi, following the structure of the original C++ implementation (P. Springer, T. Su, P. Bientinesi, "HPTT: A High-Performance Tensor Transposition C++ Library", ARRAY 2017). HPTT is licensed under BSD-3-Clause (Copyright 2018 Paul Springer); see the packaged THIRD-PARTY-LICENSES file for the full text.

This crate is therefore licensed as (MIT OR Apache-2.0) AND BSD-3-Clause.