test_piecewise.py 文件源码

def test_piecewise_fold_piecewise_in_cond():
    p1 = Piecewise((cos(x), x < 0), (0, True))
    p2 = Piecewise((0, Eq(p1, 0)), (p1 / Abs(p1), True))
    p3 = piecewise_fold(p2)
    assert(p2.subs(x, -pi/2) == 0.0)
    assert(p2.subs(x, 1) == 0.0)
    assert(p2.subs(x, -pi/4) == 1.0)
    p4 = Piecewise((0, Eq(p1, 0)), (1,True))
    assert(piecewise_fold(p4) == Piecewise(
        (0, Or(And(Eq(cos(x), 0), x < 0), Not(x < 0))), (1, True)))

    r1 = 1 < Piecewise((1, x < 1), (3, True))
    assert(piecewise_fold(r1) == Not(x < 1))

    p5 = Piecewise((1, x < 0), (3, True))
    p6 = Piecewise((1, x < 1), (3, True))
    p7 = piecewise_fold(Piecewise((1, p5 < p6), (0, True)))
    assert(Piecewise((1, And(Not(x < 1), x < 0)), (0, True)))