From d168f5c21bbfece7451df5bf3fe6179448e83762 Mon Sep 17 00:00:00 2001 From: therealyingtong Date: Thu, 12 Nov 2020 14:14:01 +0800 Subject: [PATCH] Parallelize and rename methods in msm.rs --- src/poly/commitment.rs | 4 ++-- src/poly/commitment/msm.rs | 42 +++++++++++++++++++-------------- src/poly/commitment/verifier.rs | 14 +++++------ src/poly/multiopen/verifier.rs | 4 ++-- 4 files changed, 35 insertions(+), 29 deletions(-) diff --git a/src/poly/commitment.rs b/src/poly/commitment.rs index dec70c8c..bfd4e069 100644 --- a/src/poly/commitment.rs +++ b/src/poly/commitment.rs @@ -293,7 +293,7 @@ fn test_opening_proof() { let opening_proof = opening_proof.unwrap(); // Verify the opening proof let mut commitment_msm = params.empty_msm(); - commitment_msm.add_term(Field::one(), p); + commitment_msm.append_term(Field::one(), p); let guard = opening_proof .verify( ¶ms, @@ -320,7 +320,7 @@ fn test_opening_proof() { // Check another proof to populate `msm.g_scalars` let msm = guard.use_challenges(); let mut commitment_msm = params.empty_msm(); - commitment_msm.add_term(Field::one(), p); + commitment_msm.append_term(Field::one(), p); let guard = opening_proof .verify( ¶ms, diff --git a/src/poly/commitment/msm.rs b/src/poly/commitment/msm.rs index 08c0914e..1d11d664 100644 --- a/src/poly/commitment/msm.rs +++ b/src/poly/commitment/msm.rs @@ -1,5 +1,5 @@ use super::Params; -use crate::arithmetic::{best_multiexp, Curve, CurveAffine}; +use crate::arithmetic::{best_multiexp, parallelize, Curve, CurveAffine}; /// A multiscalar multiplication in the polynomial commitment scheme #[derive(Debug, Clone)] @@ -34,52 +34,58 @@ impl<'a, C: CurveAffine> MSM<'a, C> { self.other_bases.extend(other.other_bases.iter()); if let Some(g_scalars) = &other.g_scalars { - self.add_to_g(&g_scalars); + self.add_to_g_scalars(&g_scalars); } if let Some(h_scalar) = &other.h_scalar { - self.add_to_h(*h_scalar); + self.add_to_h_scalar(*h_scalar); } } /// Add arbitrary term (the scalar and the point) - pub fn add_term(&mut self, scalar: C::Scalar, point: C) { + pub fn append_term(&mut self, scalar: C::Scalar, point: C) { self.other_scalars.push(scalar); self.other_bases.push(point); } /// Add a vector of scalars to `g_scalars`. This function will panic if the /// caller provides a slice of scalars that is not of length `params.n`. - // TODO: parallelize - pub fn add_to_g(&mut self, scalars: &[C::Scalar]) { + pub fn add_to_g_scalars(&mut self, scalars: &[C::Scalar]) { assert_eq!(scalars.len(), self.params.n as usize); if let Some(g_scalars) = &mut self.g_scalars { - for (g_scalar, scalar) in g_scalars.iter_mut().zip(scalars.iter()) { - *g_scalar += scalar; - } + parallelize(g_scalars, |g_scalars, start| { + for (g_scalar, scalar) in g_scalars.iter_mut().zip(scalars[start..].iter()) { + *g_scalar += scalar; + } + }) } else { self.g_scalars = Some(scalars.to_vec()); } } - /// Add term to h - pub fn add_to_h(&mut self, scalar: C::Scalar) { + /// Add to `h_scalar` + pub fn add_to_h_scalar(&mut self, scalar: C::Scalar) { self.h_scalar = self.h_scalar.map_or(Some(scalar), |a| Some(a + &scalar)); } /// Scale all scalars in the MSM by some scaling factor - // TODO: parallelize pub fn scale(&mut self, factor: C::Scalar) { if let Some(g_scalars) = &mut self.g_scalars { - for g_scalar in g_scalars.iter_mut() { - *g_scalar *= &factor; - } + parallelize(g_scalars, |g_scalars, _| { + for g_scalar in g_scalars { + *g_scalar *= &factor; + } + }) } - // TODO: parallelize - for other_scalar in self.other_scalars.iter_mut() { - *other_scalar *= &factor; + if !self.other_scalars.is_empty() { + parallelize(&mut self.other_scalars, |other_scalars, _| { + for other_scalar in other_scalars { + *other_scalar *= &factor; + } + }) } + self.h_scalar = self.h_scalar.map(|a| a * &factor); } diff --git a/src/poly/commitment/verifier.rs b/src/poly/commitment/verifier.rs index 02ed4d8a..70791e75 100644 --- a/src/poly/commitment/verifier.rs +++ b/src/poly/commitment/verifier.rs @@ -32,8 +32,8 @@ impl<'a, C: CurveAffine> Guard<'a, C> { /// scalars and points. pub fn use_challenges(mut self) -> MSM<'a, C> { let s = compute_s(&self.challenges_sq, self.allinv * &self.neg_z1); - self.msm.add_to_g(&s); - self.msm.add_to_h(self.neg_z1); + self.msm.add_to_g_scalars(&s); + self.msm.add_to_h_scalar(self.neg_z1); self.msm } @@ -41,7 +41,7 @@ impl<'a, C: CurveAffine> Guard<'a, C> { /// Lets caller supply the purported G point and simply appends it to /// return an updated MSM. pub fn use_g(mut self, g: C) -> (MSM<'a, C>, Accumulator) { - self.msm.add_term(self.neg_z1, g); + self.msm.append_term(self.neg_z1, g); let accumulator = Accumulator { g, @@ -176,17 +176,17 @@ impl Proof { } for (scalar, base) in extra_scalars.iter().zip(extra_bases.iter()) { - msm.add_term(*scalar, *base); + msm.append_term(*scalar, *base); } // [c * v] U - [z1 * b] U - msm.add_term((c * &v) + &(neg_z1 * &b), u); + msm.append_term((c * &v) + &(neg_z1 * &b), u); // delta - msm.add_term(Field::one(), self.delta); + msm.append_term(Field::one(), self.delta); // - [z1 - z2] H - msm.add_to_h(self.z1 - &self.z2); + msm.add_to_h_scalar(self.z1 - &self.z2); let guard = Guard { msm, diff --git a/src/poly/multiopen/verifier.rs b/src/poly/multiopen/verifier.rs index 57713f8c..6bd8a6ae 100644 --- a/src/poly/multiopen/verifier.rs +++ b/src/poly/multiopen/verifier.rs @@ -54,7 +54,7 @@ impl Proof { { let mut accumulate = |set_idx: usize, new_commitment, evals: Vec| { q_commitments[set_idx].scale(x_4); - q_commitments[set_idx].add_term(C::Scalar::one(), new_commitment); + q_commitments[set_idx].append_term(C::Scalar::one(), new_commitment); for (eval, set_eval) in evals.iter().zip(q_eval_sets[set_idx].iter_mut()) { *set_eval *= &x_4; *set_eval += eval; @@ -109,7 +109,7 @@ impl Proof { // Compute the final commitment that has to be opened let mut commitment_msm = params.empty_msm(); - commitment_msm.add_term(C::Scalar::one(), self.f_commitment); + commitment_msm.append_term(C::Scalar::one(), self.f_commitment); let (commitment_msm, msm_eval) = q_commitments.into_iter().zip(self.q_evals.iter()).fold( (commitment_msm, msm_eval), |(mut commitment_msm, msm_eval), (q_commitment, q_eval)| {