def dmp_cancel(f, g, u, K, include=True):
    """
    Cancel common factors in a rational function `f/g`.

    Examples
    ========

    >>> from sympy.polys import ring, ZZ
    >>> R, x,y = ring("x,y", ZZ)

    >>> R.dmp_cancel(2*x**2 - 2, x**2 - 2*x + 1)
    (2*x + 2, x - 1)

    """
    K0 = None

    if K.has_Field and K.has_assoc_Ring:
        K0, K = K, K.get_ring()

        cq, f = dmp_clear_denoms(f, u, K0, K, convert=True)
        cp, g = dmp_clear_denoms(g, u, K0, K, convert=True)
    else:
        cp, cq = K.one, K.one

    _, p, q = dmp_inner_gcd(f, g, u, K)

    if K0 is not None:
        _, cp, cq = K.cofactors(cp, cq)

        p = dmp_convert(p, u, K, K0)
        q = dmp_convert(q, u, K, K0)

        K = K0

    p_neg = K.is_negative(dmp_ground_LC(p, u, K))
    q_neg = K.is_negative(dmp_ground_LC(q, u, K))

    if p_neg and q_neg:
        p, q = dmp_neg(p, u, K), dmp_neg(q, u, K)
    elif p_neg:
        cp, p = -cp, dmp_neg(p, u, K)
    elif q_neg:
        cp, q = -cp, dmp_neg(q, u, K)

    if not include:
        return cp, cq, p, q

    p = dmp_mul_ground(p, cp, u, K)
    q = dmp_mul_ground(q, cq, u, K)

    return p, q
dataset/ETHPy150Open sympy/sympy/sympy/polys/euclidtools.py/dmp_cancel/original