Remove redundant add operation and allocate vector beforehand (#251)

* remove redundant add operation and allocate vector beforehand

Signed-off-by: lovesh harchandani <[email protected]>

* remove redundant iterator creation

Signed-off-by: lovesh harchandani <[email protected]>

Author: lovesh

src/r1cs/verifier.rs

@@ -373,9 +373,7 @@ impl<'a, 'b> Verifier<'a, 'b> {
         let u_for_g = iter::repeat(Scalar::one())
             .take(n1)
             .chain(iter::repeat(u).take(n2 + pad));
-        let u_for_h = iter::repeat(Scalar::one())
-            .take(n1)
-            .chain(iter::repeat(u).take(n2 + pad));
+        let u_for_h = u_for_g.clone();
 
         // define parameters for P check
         let g_scalars = yneg_wR

src/util.rs

@@ -62,13 +62,13 @@ pub fn exp_iter(x: Scalar) -> ScalarExp {
 }
 
 pub fn add_vec(a: &[Scalar], b: &[Scalar]) -> Vec<Scalar> {
-    let mut out = Vec::new();
     if a.len() != b.len() {
         // throw some error
         println!("lengths of vectors don't match for vector addition");
     }
+    let mut out = vec![Scalar::zero(); b.len()];
     for i in 0..a.len() {
-        out.push(a[i] + b[i]);
+        out[i] = a[i] + b[i];
     }
     out
 }
@@ -98,7 +98,7 @@ impl VecPoly1 {
         let n = self.0.len();
         let mut out = vec![Scalar::zero(); n];
         for i in 0..n {
-            out[i] += self.0[i] + self.1[i] * x;
+            out[i] = self.0[i] + self.1[i] * x;
         }
         out
     }
@@ -143,7 +143,7 @@ impl VecPoly3 {
         let n = self.0.len();
         let mut out = vec![Scalar::zero(); n];
         for i in 0..n {
-            out[i] += self.0[i] + x * (self.1[i] + x * (self.2[i] + x * self.3[i]));
+            out[i] = self.0[i] + x * (self.1[i] + x * (self.2[i] + x * self.3[i]));
         }
         out
     }