qi.py 文件源码

def funm_svd(a, func):
    """Apply real scalar function to singular values of a matrix.

    Args:
        a : (N, N) array_like
            Matrix at which to evaluate the function.
        func : callable
            Callable object that evaluates a scalar function f.

    Returns:
        funm : (N, N) ndarray
            Value of the matrix function specified by func evaluated at `A`.
    """
    U, s, Vh = la.svd(a, lapack_driver='gesvd')
    S = np.diag(func(s))
    return U.dot(S).dot(Vh)