Struct BitAxisFolder 

pub struct BitAxisFolder<F: BinaryField> { /* private fields */ }

A reusable folder over a fixed vector of bit-index scalars.

The one-shot function above rebuilds its lookup tables on every call. A caller folding several word-lists against the same scalar vector builds them once here, and reuses them across folds.

The word axis has a folder of its own, built the same way.

Implementations

impl<F: BinaryField> BitAxisFolder<F>

pub fn new(vec: &[F]) -> Self

Builds the folding transform for vec.

Preconditions

• vec contains exactly one scalar per bit of a word

pub fn fold<P, A>(&self, alloc: &A, words: &[Word]) -> FieldBuffer<P, A::Vec<P>>

where P: PackedField<Scalar = F>, A: Allocator,

Folds words, mapping each word to the inner product of its bits with the scalar vector.

The one-shot function at the top of this module states the exact contract.

pub fn fold_bitand_operands<P, A>( &self, alloc: &A, a_words: &[Word], b_words: &[Word], ) -> [FieldBuffer<P, A::Vec<P>>; 3]

where P: PackedField<Scalar = F>, A: Allocator,

Folds the two stored BitAnd operand columns and their derived AND column in one pass.

Overview

The BitAnd zerocheck folds three columns of the constraint A & B = C. On a satisfying witness the third column equals the AND of the first two. So this fold reads only the two stored columns and derives the third in registers:

    stream A ──┬──> fold ──> folded A
    stream B ──┼──> fold ──> folded B
               └──> A & B ──> fold ──> folded C   (no third input stream)

Returns

Three folded buffers, in order:

• the first operand column, folded as a single column would be.
• the second operand column, folded the same way.
• the word-by-word AND of the two columns, folded the same way.

The AND column is derived in registers and never written to memory.

Performance

• Two input streams instead of three.
• Two register ANDs per word pair replace one memory stream.
• The bytewise lookup tables stay hot across all three outputs.

Preconditions

• The two word-lists have equal length.

Trait Implementations

impl<F: Debug + BinaryField> Debug for BitAxisFolder<F>

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

Formats the value using the given formatter.