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lagrange_coeffs can infer the degree.

This commit is contained in:
Sean Bowe 2016-08-06 11:35:12 -06:00
parent 4ad19126df
commit ea0b341eed
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GPG Key ID: 95684257D8F8B031
1 changed files with 7 additions and 8 deletions
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15
src/lagrange.rs
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@ -1,16 +1,16 @@
use snark::{Group, Fr};
use crossbeam;
pub fn lagrange_coeffs<G: Group>(v: &[G], omega: Fr, d: usize) -> Vec<G>
pub fn lagrange_coeffs<G: Group>(v: &[G], omega: Fr) -> Vec<G>
{
const THREADS: usize = 8;
let overd = Fr::from_str(&format!("{}", d)).inverse();
let overd = Fr::from_str(&format!("{}", v.len())).inverse();
let mut tmp = fft(v, omega, THREADS);
tmp.reverse(); // coefficients are in reverse
crossbeam::scope(|scope| {
for i in tmp.chunks_mut(d / THREADS) {
for i in tmp.chunks_mut(v.len() / THREADS) {
scope.spawn(move || {
for i in i {
*i = *i * overd;
@ -96,18 +96,17 @@ mod test {
let powers_of_tau_g2 = TauPowers::new(tau).take(d).map(|e| G2::one() * e).collect::<Vec<_>>();
// Perform FFT to compute lagrange coeffs in G1/G2
let overd = Fr::from_str(&format!("{}", d)).inverse();
let lc1 = lagrange_coeffs(&powers_of_tau_g1, omega, d);
let lc2 = lagrange_coeffs(&powers_of_tau_g2, omega, d);
let lc1 = lagrange_coeffs(&powers_of_tau_g1, omega);
let lc2 = lagrange_coeffs(&powers_of_tau_g2, omega);
{
// Perform G1 FFT with wrong omega
let lc1 = lagrange_coeffs(&powers_of_tau_g1, Fr::random(), d);
let lc1 = lagrange_coeffs(&powers_of_tau_g1, Fr::random());
assert!(!compare_tau(&lc1, &lc2, &tau, &cs));
}
{
// Perform G2 FFT with wrong omega
let lc2 = lagrange_coeffs(&powers_of_tau_g2, Fr::random(), d);
let lc2 = lagrange_coeffs(&powers_of_tau_g2, Fr::random());
assert!(!compare_tau(&lc1, &lc2, &tau, &cs));
}