length p returns the length of a given array p

get p i returns the i-th element of a given array p

build log computes [one; g; ..; g^{n-1}] where g is a primitive n-th root of unity and n = 2^log

subgroup log d returns a subgroup of d of order 2^log

inverse d returns for a domain wⁱᵢ its inverse domain w⁻ⁱᵢ