Remove duplicate function scale_by_cofactor()

CHANGELOG.md

@@ -14,7 +14,8 @@
 - [\#359](https://github.com/arkworks-rs/algebra/pull/359) (ark-test-templates) Simplify the field and curve test macros.
 - [\#365](https://github.com/arkworks-rs/algebra/pull/365) (arc-ec)
 	- Move `COFACTOR`, `COFACTOR_INV`, and `is_in_correct_subgroup_assuming_on_curve()` from `{SW,TE}ModelParameters` to `ModelParameters`. 
-	- Add `mul_bits` to `AffineCurve` and provide a default implementation of `mul` using this.
+	- Add `mul_bits()` to `AffineCurve` and provide a default implementation of `mul()` using this.
+    - Remove duplicate function `scale_by_cofactor()` from `short_weierstrass_jacobian::GroupAffine` and `twisted_edwards_extended::GroupAffine`
 
 ### Features
 

ec/src/models/short_weierstrass_jacobian.rs

@@ -74,12 +74,6 @@ impl<P: Parameters> GroupAffine<P> {
         Self { x, y, infinity }
     }
 
-    /// Multiply `self` by the cofactor of the curve, `P::COFACTOR`.
-    pub fn scale_by_cofactor(&self) -> GroupProjective<P> {
-        let cofactor = BitIteratorBE::new(P::COFACTOR);
-        self.mul_bits(cofactor)
-    }
-
     /// Attempts to construct an affine point given an x-coordinate. The
     /// point is not guaranteed to be in the prime order subgroup.
     ///
@@ -180,7 +174,7 @@ impl<P: Parameters> Distribution<GroupAffine<P>> for Standard {
             let greatest = rng.gen();
 
             if let Some(p) = GroupAffine::get_point_from_x(x, greatest) {
-                return p.scale_by_cofactor().into();
+                return p.mul_by_cofactor();
             }
         }
     }
@@ -218,7 +212,7 @@ impl<P: Parameters> AffineCurve for GroupAffine<P> {
 
     #[inline]
     fn mul_by_cofactor_to_projective(&self) -> Self::Projective {
-        self.scale_by_cofactor()
+        self.mul_bits(BitIteratorBE::new(P::COFACTOR))
     }
 
     fn mul_by_cofactor_inv(&self) -> Self {
@@ -342,7 +336,7 @@ impl<P: Parameters> Distribution<GroupProjective<P>> for Standard {
             let greatest = rng.gen();
 
             if let Some(p) = GroupAffine::get_point_from_x(x, greatest) {
-                return p.scale_by_cofactor().into();
+                return p.mul_by_cofactor_to_projective();
             }
         }
     }

ec/src/models/twisted_edwards_extended.rs

@@ -57,11 +57,6 @@ impl<P: Parameters> GroupAffine<P> {
         Self { x, y }
     }
 
-    #[must_use]
-    pub fn scale_by_cofactor(&self) -> <Self as AffineCurve>::Projective {
-        self.mul_bits(BitIteratorBE::new(P::COFACTOR))
-    }
-
     /// Attempts to construct an affine point given an y-coordinate. The
     /// point is not guaranteed to be in the prime order subgroup.
     ///
@@ -144,7 +139,7 @@ impl<P: Parameters> AffineCurve for GroupAffine<P> {
 
     #[inline]
     fn mul_by_cofactor_to_projective(&self) -> Self::Projective {
-        self.scale_by_cofactor()
+        self.mul_bits(BitIteratorBE::new(P::COFACTOR))
     }
 
     fn mul_by_cofactor_inv(&self) -> Self {
@@ -250,7 +245,7 @@ impl<P: Parameters> Distribution<GroupAffine<P>> for Standard {
             let greatest = rng.gen();
 
             if let Some(p) = GroupAffine::get_point_from_y(y, greatest) {
-                return p.scale_by_cofactor().into();
+                return p.mul_by_cofactor();
             }
         }
     }
@@ -349,7 +344,7 @@ impl<P: Parameters> Distribution<GroupProjective<P>> for Standard {
             let greatest = rng.gen();
 
             if let Some(p) = GroupAffine::get_point_from_y(y, greatest) {
-                return p.scale_by_cofactor();
+                return p.mul_by_cofactor_to_projective();
             }
         }
     }

test-curves/src/bn384_small_two_adicity/g1.rs

@@ -4,7 +4,7 @@ use ark_ec::{
 };
 use ark_ff::{field_new, Zero};
 
-use crate::bn384_small_two_adicity::{Fq, Fr};
+use crate::bn384_small_two_adicity::{Fq, Fr, FR_ONE};
 
 pub type G1Affine = GroupAffine<Parameters>;
 pub type G1Projective = GroupProjective<Parameters>;
@@ -18,10 +18,10 @@ impl ModelParameters for Parameters {
     type Affine = GroupAffine<Self>;
 
     /// COFACTOR = 1
-    const COFACTOR: &'static [u64] = &[0x1];
+    const COFACTOR: &'static [u64] = &[1];
 
     /// COFACTOR_INV = COFACTOR^{-1} mod r = 1
-    const COFACTOR_INV: Fr = field_new!(Fr, "1");
+    const COFACTOR_INV: Fr = FR_ONE;
 }
 
 impl SWModelParameters for Parameters {

test-curves/src/mnt4_753/g1.rs

@@ -20,8 +20,7 @@ impl ModelParameters for Parameters {
     /// COFACTOR = 1
     const COFACTOR: &'static [u64] = &[1];
 
-    /// COFACTOR^(-1) mod r =
-    /// 1
+    /// COFACTOR^(-1) mod r = 1
     #[rustfmt::skip]
     const COFACTOR_INV: Fr = FR_ONE;
 }

test-templates/src/lib.rs

@@ -193,7 +193,7 @@ macro_rules! generate_g1_generator_raw_test {
                     let p = G1Affine::new(x, if y < -y { y } else { -y }, false);
                     assert!(!p.is_in_correct_subgroup_assuming_on_curve());
 
-                    let g1 = p.scale_by_cofactor();
+                    let g1 = p.mul_by_cofactor_to_projective();
                     if !g1.is_zero() {
                         assert_eq!(i, $const);
                         let g1 = G1Affine::from(g1);