docs: def sin_fc(fdata):
      """Apply sine in the Fourier domain."""
  
      nrows = fdata.shape[0]
      ncols = fdata.shape[1]
  
      M = nrows / 2
      fdata[int(M - 1), :] = 0
      fdata[int(M + 1), :] = 0
      
      work1 = np.zeros([nrows, ncols], dtype=np.complex128)
      work2 = np.zeros([nrows, ncols], dtype=np.complex128)
  
      work1[0, :] = fdata[-1, :]
      work1[1:, :] = fdata[0:-1, :]
  
      work2[0:-1] = fdata[1:, :]
      work2[-1, :] = fdata[0, :]
  
      fdata[:, :] = 1.0 / (2 * 1j) * (work1 - work2)