use gnark API for Add

crypto/bn256/gnark/g1.go

@@ -20,25 +20,7 @@ type G1 struct {
 
 // Add adds `a` and `b` together storing the result in `g`
 func (g *G1) Add(a, b *G1) {
-	// TODO(Decision to be made): There are three ways to
-	// TODO do this addition. Each with different performance
-	// TODO: characteristics.
-	//
-	// Option 1: This just calls a method in gnark
-	// g.inner.Add(&a.inner, &b.inner)
-
-	// Option 2: This calls multiple methods in gnark
-	// but is faster.
-	//
-	// var res bn254.G1Jac
-	// res.FromAffine(&a.inner)
-	// res.AddMixed(&b.inner)
-	// g.inner.FromJacobian(&res)
-
-	// Option 3: This calls a method that I created that
-	// we can upstream to gnark.
-	// This should be the fastest, I can write the same for G2
-	g.addAffine(a, b)
+	g.inner.Add(&a.inner, &b.inner)
 }
 
 // ScalarMult computes the scalar multiplication between `a` and

crypto/bn256/gnark/g1_aff.go

@@ -1,73 +0,0 @@
-package bn256
-
-import (
-	"github.com/consensys/gnark-crypto/ecc/bn254/fp"
-)
-
-// This is just the addition formula
-// but given we know that we do not need Jacobian
-// coordinates, we use the naive implementation.
-//
-// Ideally, we push this into gnark
-func (g *G1) addAffine(a_, b_ *G1) {
-
-	// Get the gnark specific points
-	var a = a_.inner
-	var b = b_.inner
-
-	// If a is 0, then return b
-	if a.IsInfinity() {
-		g.inner.Set(&b)
-		return
-	}
-
-	// If b is 0, then return a
-	if b.IsInfinity() {
-		g.inner.Set(&a)
-		return
-	}
-
-	// If a == -b, then return 0
-	g.inner.Neg(&b)
-	if a.Equal(&g.inner) {
-		g.inner.X.SetZero()
-		g.inner.Y.SetZero()
-		return
-	}
-
-	// Compute lambda based on whether we
-	// are doing a point addition or a point doubling
-	//
-	// Check if points are equal
-	var pointsAreEqual = a.Equal(&b)
-
-	var denominator fp.Element
-	var lambda fp.Element
-
-	// If a == b, then we need to compute lambda for double
-	// else we need to compute lambda for addition
-	if pointsAreEqual {
-		// Compute numerator
-		lambda.Square(&a.X)
-		fp.MulBy3(&lambda)
-
-		denominator.Add(&a.Y, &a.Y)
-	} else {
-		// Compute numerator
-		lambda.Sub(&b.Y, &a.Y)
-
-		denominator.Sub(&b.X, &a.X)
-	}
-	denominator.Inverse(&denominator)
-	lambda.Mul(&lambda, &denominator)
-
-	// Compute x_3 as lambda^2 - a_x - b_x
-	g.inner.X.Square(&lambda)
-	g.inner.X.Sub(&g.inner.X, &a.X)
-	g.inner.X.Sub(&g.inner.X, &b.X)
-
-	// Compute y as lambda * (a_x - x_3) - a_y
-	g.inner.Y.Sub(&a.X, &g.inner.X)
-	g.inner.Y.Mul(&g.inner.Y, &lambda)
-	g.inner.Y.Sub(&g.inner.Y, &a.Y)
-}