github.com/consensys/gnark-crypto@v0.14.0/ecc/bls24-317/internal/fptower/e4_bls315.go (about)

     1  // Copyright 2020 ConsenSys AG
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package fptower
    16  
    17  // MulBybTwistCurveCoeff multiplies by 4*(0,1)
    18  func (z *E4) MulBybTwistCurveCoeff(x *E4) *E4 {
    19  
    20  	var res E4
    21  	res.B1.Set(&x.B0)
    22  	res.B0.MulByNonResidue(&x.B1)
    23  
    24  	z.Double(&res).
    25  		Double(z)
    26  
    27  	return z
    28  }