test_subresultants_qq_zz.py 文件源码

def test_modified_subresultants_bezout():
    x = var('x')

    p = x**8 + x**6 - 3*x**4 - 3*x**3 + 8*x**2 + 2*x - 5
    q = 3*x**6 + 5*x**4 - 4*x**2 - 9*x + 21
    amv_factors = [1, 1, -1, 1, -1, 1]
    assert modified_subresultants_bezout(p, q, x) == [i*j for i, j in zip(amv_factors, subresultants_amv(p, q, x))]
    assert modified_subresultants_bezout(p, q, x)[-1] != sylvester(p + x**8, q, x).det()
    assert modified_subresultants_bezout(p, q, x) != sturm_amv(p, q, x)

    p = x**3 - 7*x + 7
    q = 3*x**2 - 7
    assert modified_subresultants_bezout(p, q, x) == sturm_amv(p, q, x)
    assert modified_subresultants_bezout(-p, q, x) != sturm_amv(-p, q, x)