distribution_util_test.py 文件源码

def _fill_lower_triangular(self, x):
    """Numpy implementation of `fill_lower_triangular`."""
    x = np.asarray(x)
    d = x.shape[-1]
    # d = n(n+1)/2 implies n is:
    n = int(0.5 * (math.sqrt(1. + 8. * d) - 1.))
    ids = np.tril_indices(n)
    y = np.zeros(list(x.shape[:-1]) + [n, n], dtype=x.dtype)
    y[..., ids[0], ids[1]] = x
    return y