def assess_angmom(X):
    """
        Checks for change of sign in each component of the angular momentum.
        Returns an array with ith entry 1 if no sign change in i component
        and 0 if sign change.
        Box = (0,0,0)
        S.A loop = (0,0,1)
        L.A loop = (1,0,0)
    """
    L=angmom(X[0])
    loop = np.array([1,1,1])
    for i in X[1:]:
        L0 = angmom(i)
        if(L0[0]*L[0]<0.):
            loop[0] = 0
        if(L0[1]*L[1]<0.):
            loop[1] = 0
        if(L0[2]*L[2]<0.):
            loop[2] = 0
    return loop