Create simple moving matrix.

    Parameters
    ----------
    x : ndarray
        A numpy array
    n : integer
        The number of sample points used to make average

    Returns
    -------
    ndarray
        A n x n numpy array which will be useful for calculating confidentail
        interval of simple moving average

def simple_moving_matrix(x, n=10):
    """
    Create simple moving matrix.

    Parameters
    ----------
    x : ndarray
        A numpy array
    n : integer
        The number of sample points used to make average

    Returns
    -------
    ndarray
        A n x n numpy array which will be useful for calculating confidentail
        interval of simple moving average

    """
    if x.ndim > 1 and len(x[0]) > 1:
        x = np.average(x, axis=1)
    h = n / 2
    o = 0 if h * 2 == n else 1
    xx = []
    for i in range(h, len(x) - h):
        xx.append(x[i-h:i+h+o])
    return np.array(xx)