Struct LowStageTwiddles 

pub struct LowStageTwiddles { /* private fields */ }

The twiddles of the lowest LOW_STAGES stages of a single-column additive transform.

Stage j pairs elements 2^j apart, and block b of that stage, its 2^(j+1) elements from 2^(j+1) b on, scales by one twiddle, affine in b:

    twiddle(j, b) = shifts[j] + Σ basis[k]    over the set bits k of b

A run of 2^LOW_STAGES elements is closed under all of those stages, so they run together while the run sits in registers, instead of in one sweep of the slice each.

Implementations

impl LowStageTwiddles

pub fn new(shifts: &[u128], basis: &[u128]) -> Self

The twiddles of a transform with these stage shifts and this block basis.

Panics

Panics if shifts holds fewer than LOW_STAGES stages, or basis holds fewer than LOW_STAGES - 1 elements.

pub fn forward(&self, values: &mut [u128], first_run: usize)

Runs the low stages of the forward transform over values.

values starts at element 2^LOW_STAGES · first_run of the transform, and ends on a whole run of 2^LOW_STAGES elements.

Panics

Panics if values ends inside a run, or if a run lies past the basis the twiddles hold.

Trait Implementations

impl Clone for LowStageTwiddles

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for LowStageTwiddles

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.