pub fn convolution<T: FFT>(a: &[T], b: &[T]) -> Vec<T>Expand description
Given two polynomials (vectors) sum_i a[i] x^i and sum_i b[i] x^i, computes their product (convolution) c[k] = sum_(i+j=k) a[i]*b[j]. Uses complex FFT if inputs are f64, or modular NTT if inputs are i64.