fourier.py 文件源码

def Idag(v=None, cell=None):
    """Computes the complex conjugate of the `I` operator for Fourier basis.

    Args:
        v (numpy.ndarray): if None, then return the matrix :math:`\mathbb{I^\dag}`,
          else, return :math:`\mathbb{I^\dag}\cdot v`.
        cell (pydft.geometry.Cell): that describes the unit cell and
          sampling points for real and reciprocal space.
    """
    #It turns out that for Fourier, the complex conjugate only differs by a -1
    #on the i (symmetric in R and G), so that we can return J instead.
    cell = get_cell(cell)
    def ifft(X):
        FB = np.fft.ifftn(np.reshape(X, cell.S, order='F'))
        return np.reshape(FB, X.shape, order='F')
    return matprod(ifft, v)*np.prod(cell.S)