tools_fri_doa_plane.py 文件源码

def output_shrink(K, L):
    """
    shrink the convolution output to half the size.
    used when both the annihilating filter and the uniform samples of sinusoids satisfy
    Hermitian symmetric.
    :param K: the annihilating filter size: K + 1
    :param L: length of the (complex-valued) b vector
    :return:
    """
    out_len = L - K
    if out_len % 2 == 0:
        half_out_len = np.int(out_len / 2.)
        mtx_r = np.hstack((np.eye(half_out_len),
                           np.zeros((half_out_len, half_out_len))))
        mtx_i = mtx_r
    else:
        half_out_len = np.int((out_len + 1) / 2.)
        mtx_r = np.hstack((np.eye(half_out_len),
                           np.zeros((half_out_len, half_out_len - 1))))
        mtx_i = np.hstack((np.eye(half_out_len - 1),
                           np.zeros((half_out_len - 1, half_out_len))))
    return linalg.block_diag(mtx_r, mtx_i)