Struct AdditiveFft 

pub struct AdditiveFft<F> { /* private fields */ }

In-place additive FFT over a 2^log_n subspace of a binary tower field. Transforms return Err(FftError::BadLength) unless data.len() == 2^log_n; on success the buffer is overwritten in place.

Implementations

impl<F: BinaryFieldExtras + HardwareField> AdditiveFft<F>

pub fn new(log_n: u32) -> Self

Derives the Cantor basis (via solve_quadratic) and the twiddle schedule for transform size 2^log_n. This one-time allocation is the only heap use; the transforms are in-place.

Panics

If log_n is not in 1..=min(F::BITS, 63), or F admits no Cantor basis of that size.

pub fn forward_scalar(&self, data: &mut [Flat<F>]) -> Result<(), FftError>

Forward: novel-basis coefficients to evaluations.

pub fn inverse_scalar(&self, data: &mut [Flat<F>]) -> Result<(), FftError>

Inverse: evaluations to novel-basis coefficients.

pub fn forward_coset_scalar( &self, data: &mut [Flat<F>], offset: Flat<F>, ) -> Result<(), FftError>

Forward over the coset offset + W_log_n.

pub fn inverse_coset_scalar( &self, data: &mut [Flat<F>], offset: Flat<F>, ) -> Result<(), FftError>

Inverse over the coset offset + W_log_n.

pub fn forward(&self, data: &mut [PackedFlat<F>]) -> Result<(), FftError>

Forward, F::WIDTH column-lanes per element in lockstep.

pub fn inverse(&self, data: &mut [PackedFlat<F>]) -> Result<(), FftError>

Inverse, F::WIDTH column-lanes per element in lockstep.

pub fn forward_coset( &self, data: &mut [PackedFlat<F>], offset: Flat<F>, ) -> Result<(), FftError>

Packed forward over the coset offset + W_log_n.

pub fn inverse_coset( &self, data: &mut [PackedFlat<F>], offset: Flat<F>, ) -> Result<(), FftError>

Packed inverse over the coset offset + W_log_n.