FromInterface converts an interface to a big.Int element input must be primitive (uintXX, intXX, []byte, string) or implement BigInt(res *big.Int) (which is the case for gnark-crypto field elements) if the input is a string, it calls (big.Int).SetString(input, 0).

pad to 2^n gates (and 4^n for first layer) 4^n exists for historical reasons, not used now.

SortIntSeq sorts an integer sequence using a given compare function.