def isleftorequal(a, b, c):
    """ Test if point c is on the left of the vector a-->b

    Parameters
    ----------

    a : np.array (2xN)
    b : np.array (2xN)
    c : np.array (2xN)

    Returns
    -------

    boolean array (1xN)

    See Also
    --------

    isleft

    """
    return ((b[0, :] - a[0, :]) * (c[1, :] - a[1, :])) - ((b[1, :] - a[1, :]) * (c[0, :] - a[0, :])) >= 0