factory.py 文件源码

def _unitary_haar(dim, randstate=None):
    """Returns a sample from the Haar measure of the unitary group of given
    dimension.

    :param int dim: Dimension
    :param randn: Function to create real N(0,1) distributed random variables.
        It should take the shape of the output as numpy.random.randn does
        (default: numpy.random.randn)
    """
    z = _zrandn((dim, dim), randstate) / np.sqrt(2.0)
    q, r = qr(z)
    d = np.diagonal(r)
    ph = d / np.abs(d)
    return q * ph