github.com/jingcheng-WU/gonum@v0.9.1-0.20210323123734-f1a2a11a8f7b/dsp/fourier/internal/fftpack/helpers.go (about)

     1  // Copyright ©2020 The Gonum Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package fftpack
     6  
     7  // swap returns c with the real and imaginary parts swapped.
     8  func swap(c complex128) complex128 {
     9  	return complex(imag(c), real(c))
    10  }
    11  
    12  // scale scales the complex number c by f.
    13  func scale(f float64, c complex128) complex128 {
    14  	return complex(f*real(c), f*imag(c))
    15  }