test_simplify.py 文件源码

def test_collect_order():
    a, b, x, t = symbols('a,b,x,t')

    assert collect(t + t*x + t*x**2 + O(x**3), t) == t*(1 + x + x**2 + O(x**3))
    assert collect(t + t*x + x**2 + O(x**3), t) == \
        t*(1 + x + O(x**3)) + x**2 + O(x**3)

    f = a*x + b*x + c*x**2 + d*x**2 + O(x**3)
    g = x*(a + b) + x**2*(c + d) + O(x**3)

    assert collect(f, x) == g
    assert collect(f, x, distribute_order_term=False) == g

    f = sin(a + b).series(b, 0, 10)

    assert collect(f, [sin(a), cos(a)]) == \
        sin(a)*cos(b).series(b, 0, 10) + cos(a)*sin(b).series(b, 0, 10)
    assert collect(f, [sin(a), cos(a)], distribute_order_term=False) == \
        sin(a)*cos(b).series(b, 0, 10).removeO() + \
        cos(a)*sin(b).series(b, 0, 10).removeO() + O(b**10)