def array2image(array, nx=0, ny=0):
    """
    returns the information contained in a 1d array into an n*n 2d array (only works when lenght of array is n**2)

    :param array: image values
    :type array: array of size n**2
    :returns:  2d array
    :raises: AttributeError, KeyError
    """
    if nx == 0 or ny == 0:
        n = int(np.sqrt(len(array)))
        if n**2 != len(array):
            raise ValueError("lenght of input array given as %s is not square of integer number!" %(len(array)))
        nx, ny = n, n
    image = array.reshape(int(nx), int(ny))
    return image