Information about the zufft build — zufft

Reports which ducc0 source zufft was built from and how: the vendored commit and the SciPy commit that pins it, the SIMD backend and vector width the compiler selected, whether the target has fused multiply-add instructions, the threading mode, and the thread pool.

Usage

zufft_info()

Value

A named list:

ducc0_commit: ducc0 commit of the vendored FFT subset.
scipy_commit: SciPy commit whose vendoring script pins it.
simd_backend: "ducc0", "std::experimental::simd" or "none".
simd_width: Doubles per SIMD vector, 1 without SIMD.
fma: TRUE if the target has fused multiply-add.
fp_contract: "off" when the transforms never fuse multiply-adds, so results are bit-identical whatever workers is; "fast" for a GCC build targeting FMA hardware, where they can differ in the last bit. CRAN's builds are "off".
threading: "zufft" when zufft supplies the thread pool, "none" when threads are compiled out.
pool_size: Threads the pool can use now, the caller included.
hardware_threads: Threads the hardware offers.
complex_path: "zero-copy" when complex vectors are viewed in place, "marshal" when they are copied (design §12.2).

Examples

zufft_info()$simd_width
#> [1] 2