Function ark_ff::biginteger::arithmetic::find_relaxed_naf

pub fn find_relaxed_naf(num: &[u64]) -> Vec<i8>

We define relaxed NAF as a variant of NAF with a very small tweak.

Note that the cost of scalar multiplication grows with the length of the sequence (for doubling) plus the Hamming weight of the sequence (for addition, or subtraction).

NAF is optimizing for the Hamming weight only and therefore can be suboptimal. For example, NAF may generate a sequence (in little-endian) of the form …0 -1 0 1.

This can be rewritten as …0 1 1 to avoid one doubling, at the cost that we are making an exception of non-adjacence for the most significant bit.

Since this representation is no longer a strict NAF, we call it “relaxed NAF”.