v.Z.Subtract(&Z2, &TT2d) // flipped sign v.T.Add(&Z2, &TT2d) // flipped sign return v } // Doubling. func (v *projP1xP1) Double(p *projP2) *projP1xP1 { var XX, YY, ZZ2, XplusYsq field.Element XX.Square(&p.X) YY.Square(&p.Y) ZZ2.Square(&p.Z) ZZ2.Add(&ZZ2, &ZZ2) XplusYsq.Add(&p.X, &p.Y) XplusYsq.Square(&XplusYsq) v.Y.Add(&YY, &XX) v.Z.Subtract(&YY, &XX) v.X.Subtract(&XplusYsq, &v.Y) v.T.Subtract(&ZZ2, &v.Z) return v } // Negation. // Negate sets v = -p, and returns v. func (v *Point) Negate(p *Point) *Point...