utility.py 文件源码

def inv_sqrth(x):
    """
    Matrix inverse square root

    Parameters
    ----------
    x : ndarray
        Real, symmetric matrix

    Returns
    -------
    invsqrt : ndarray
        Input to the power -1/2
    """
    vals, vecs = eigh(x)
    return vecs @ diag(1 / sqrt(vals)) @ vecs.T