extmath.py 文件源码

def _standard_normal(shape, randstate=np.random, dtype=np.float_):
    """Generates a standard normal numpy array of given shape and dtype, i.e.
    this function is equivalent to `randstate.randn(*shape)` for real dtype and
    `randstate.randn(*shape) + 1.j * randstate.randn(shape)` for complex dtype.

    :param tuple shape: Shape of array to be returned
    :param randstate: An instance of :class:`numpy.random.RandomState` (default is
        ``np.random``))
    :param dtype: ``np.float_`` (default) or `np.complex_`

    Returns
    -------

    A: An array of given shape and dtype with standard normal entries

    """
    if dtype == np.float_:
        return randstate.randn(*shape)
    elif dtype == np.complex_:
        return randstate.randn(*shape) + 1.j * randstate.randn(*shape)
    else:
        raise ValueError('{} is not a valid dtype.'.format(dtype))