From 15a9826e3ce7469dc408bc6c71952196d8f0f112 Mon Sep 17 00:00:00 2001
From: Daniel Lubarov <daniel@lubarov.com>
Date: Mon, 3 Aug 2020 11:55:21 -0700
Subject: [PATCH] Some minor tweaks (#21)

Minor tweaks
---
 src/commitments.rs  | 13 +++++++------
 src/dense_mlpoly.rs |  7 +++----
 src/nizk/bullet.rs  |  4 ++--
 src/nizk/mod.rs     |  2 +-
 src/unipoly.rs      |  6 +++---
 5 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/src/commitments.rs b/src/commitments.rs
index 3108000..8cc9112 100644
--- a/src/commitments.rs
+++ b/src/commitments.rs
@@ -1,7 +1,8 @@
 use super::group::{GroupElement, VartimeMultiscalarMul, GROUP_BASEPOINT_COMPRESSED};
 use super::scalar::Scalar;
-use digest::{ExtendableOutput, Input, XofReader};
+use digest::{ExtendableOutput, Input};
 use sha3::Shake256;
+use std::io::Read;
 
 #[derive(Debug)]
 pub struct MultiCommitGens {
@@ -20,7 +21,7 @@ impl MultiCommitGens {
     let mut gens: Vec<GroupElement> = Vec::new();
     let mut uniform_bytes = [0u8; 64];
     for _ in 0..n + 1 {
-      reader.read(&mut uniform_bytes);
+      reader.read_exact(&mut uniform_bytes).unwrap();
       gens.push(GroupElement::from_uniform_bytes(&uniform_bytes));
     }
 
@@ -39,8 +40,8 @@ impl MultiCommitGens {
     }
   }
 
-  pub fn split_at_mut(&mut self, mid: usize) -> (MultiCommitGens, MultiCommitGens) {
-    let (G1, G2) = self.G.split_at_mut(mid);
+  pub fn split_at(&self, mid: usize) -> (MultiCommitGens, MultiCommitGens) {
+    let (G1, G2) = self.G.split_at(mid);
 
     (
       MultiCommitGens {
@@ -63,14 +64,14 @@ pub trait Commitments {
 
 impl Commitments for Scalar {
   fn commit(&self, blind: &Scalar, gens_n: &MultiCommitGens) -> GroupElement {
-    assert!(gens_n.n == 1);
+    assert_eq!(gens_n.n, 1);
     GroupElement::vartime_multiscalar_mul(&[*self, *blind], &[gens_n.G[0], gens_n.h])
   }
 }
 
 impl Commitments for Vec<Scalar> {
   fn commit(&self, blind: &Scalar, gens_n: &MultiCommitGens) -> GroupElement {
-    assert!(gens_n.n == self.len());
+    assert_eq!(gens_n.n, self.len());
     GroupElement::vartime_multiscalar_mul(self, &gens_n.G) + blind * gens_n.h
   }
 }
diff --git a/src/dense_mlpoly.rs b/src/dense_mlpoly.rs
index f12f6c6..3c836c1 100644
--- a/src/dense_mlpoly.rs
+++ b/src/dense_mlpoly.rs
@@ -16,7 +16,7 @@ use rayon::prelude::*;
 
 #[derive(Debug)]
 pub struct DensePolynomial {
-  num_vars: usize, //the number of variables in the multilinear polynomial
+  num_vars: usize, // the number of variables in the multilinear polynomial
   len: usize,
   Z: Vec<Scalar>, // evaluations of the polynomial in all the 2^num_vars Boolean inputs
 }
@@ -148,8 +148,7 @@ impl DensePolynomial {
     let R_size = self.Z.len() / L_size;
     assert_eq!(L_size * R_size, self.Z.len());
     let C = (0..L_size)
-      .collect::<Vec<usize>>()
-      .par_iter()
+      .into_par_iter()
       .map(|&i| {
         self.Z[R_size * i..R_size * (i + 1)]
           .commit(&blinds[i], gens)
@@ -207,7 +206,7 @@ impl DensePolynomial {
     let R_size = right_num_vars.pow2();
     (0..R_size)
       .map(|i| (0..L_size).map(|j| L[j] * self.Z[j * R_size + i]).sum())
-      .collect::<Vec<Scalar>>()
+      .collect()
   }
 
   pub fn bound_poly_var_top(&mut self, r: &Scalar) {
diff --git a/src/nizk/bullet.rs b/src/nizk/bullet.rs
index 902e322..0224932 100644
--- a/src/nizk/bullet.rs
+++ b/src/nizk/bullet.rs
@@ -168,8 +168,8 @@ impl BulletReductionProof {
 
     // 3. Compute u_i^2 and (1/u_i)^2
     for i in 0..lg_n {
-      challenges[i] = challenges[i] * challenges[i];
-      challenges_inv[i] = challenges_inv[i] * challenges_inv[i];
+      challenges[i] = challenges[i].square();
+      challenges_inv[i] = challenges_inv[i].square();
     }
     let challenges_sq = challenges;
     let challenges_inv_sq = challenges_inv;
diff --git a/src/nizk/mod.rs b/src/nizk/mod.rs
index bf0137d..0cfb592 100644
--- a/src/nizk/mod.rs
+++ b/src/nizk/mod.rs
@@ -415,7 +415,7 @@ pub struct DotProductProofGens {
 
 impl DotProductProofGens {
   pub fn new(n: usize, label: &[u8]) -> Self {
-    let (gens_n, gens_1) = MultiCommitGens::new(n + 1, label).split_at_mut(n);
+    let (gens_n, gens_1) = MultiCommitGens::new(n + 1, label).split_at(n);
     DotProductProofGens { n, gens_n, gens_1 }
   }
 }
diff --git a/src/unipoly.rs b/src/unipoly.rs
index a6db038..895b24d 100644
--- a/src/unipoly.rs
+++ b/src/unipoly.rs
@@ -103,9 +103,9 @@ impl CompressedUniPoly {
     }
 
     let mut coeffs: Vec<Scalar> = Vec::new();
-    coeffs.extend(vec![&self.coeffs_except_linear_term[0]]);
-    coeffs.extend(vec![&linear_term]);
-    coeffs.extend(self.coeffs_except_linear_term[1..].to_vec());
+    coeffs.push(self.coeffs_except_linear_term[0]);
+    coeffs.push(linear_term);
+    coeffs.extend(&self.coeffs_except_linear_term[1..]);
     assert_eq!(self.coeffs_except_linear_term.len() + 1, coeffs.len());
     UniPoly { coeffs }
   }