# Copyright (c) 2015, Disney Research

# All rights reserved.

#

# Author(s): Sehoon Ha <sehoon.ha@disneyresearch.com>

# Disney Research Robotics Group

import numpy as np

def grad(fun, x, h):

    n = len(x)

    g = np.zeros(n)

    for i in range(n):

        dx = np.zeros(n)

        dx[i] = h

        f1 = fun(x - dx)

        f2 = fun(x + dx)

        g[i] = (0.5 * f2 - 0.5 * f1) / h

    return g