Function rotr_ind

pub fn rotr_ind<F: Field>(i: &[F], j: &[F], s: &[F]) -> F

Computes the multilinear extension of the rotate right indicator at a point.

The shift indicator for rotate right (rotr) evaluates to 1 when bit i of the output equals bit j of the input after rotating right by s positions. Unlike logical shifts, bits that shift off one end wrap around to the other end. Specifically:

• rotr_ind(i, j, s) = 1 if and only if j = (i + s) mod 2^k
• rotr_ind(i, j, s) = 0 otherwise

This function evaluates the multilinear extension of this indicator at the given point (i, j, s) where each coordinate is a field element.

Arguments

• i - Slice of field elements representing the output bit position (length k)
• j - Slice of field elements representing the input bit position (length k)
• s - Slice of field elements representing the shift amount (length k)

Panics

Panics if the slices don’t all have the same length.