Python densebasic.dmp_zero_p函数代码示例

def dmp_mul_term(f, c, i, u, K):
    """
    Multiply ``f`` by ``c(x_2..x_u)*x_0**i`` in ``K[X]``.

    **Examples**

    >>> from sympy.polys.domains import ZZ
    >>> from sympy.polys.densearith import dmp_mul_term

    >>> f = ZZ.map([[1, 0], [1], []])
    >>> c = ZZ.map([3, 0])

    >>> dmp_mul_term(f, c, 2, 1, ZZ)
    [[3, 0, 0], [3, 0], [], [], []]

    """
    if not u:
        return dup_mul_term(f, c, i, K)

    v = u-1

    if dmp_zero_p(f, u):
        return f
    if dmp_zero_p(c, v):
        return dmp_zero(u)
    else:
        return [ dmp_mul(cf, c, v, K) for cf in f ] + dmp_zeros(i, v, K)

def dmp_mul_term(f, c, i, u, K):
    """
    Multiply ``f`` by ``c(x_2..x_u)*x_0**i`` in ``K[X]``.

    Examples
    ========

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

    >>> R.dmp_mul_term(x**2*y + x, 3*y, 2)
    3*x**4*y**2 + 3*x**3*y

    """
    if not u:
        return dup_mul_term(f, c, i, K)

    v = u - 1

    if dmp_zero_p(f, u):
        return f
    if dmp_zero_p(c, v):
        return dmp_zero(u)
    else:
        return [ dmp_mul(cf, c, v, K) for cf in f ] + dmp_zeros(i, v, K)

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

    **Examples**

    >>> from sympy.polys.domains import ZZ
    >>> from sympy.polys.euclidtools import dmp_cancel

    >>> f = ZZ.map([[2], [0], [-2]])
    >>> g = ZZ.map([[1], [-2], [1]])

    >>> dmp_cancel(f, g, 1, ZZ)
    ([[2], [2]], [[1], [-1]])

    """
    if dmp_zero_p(f, u) or dmp_zero_p(g, u):
        if multout:
            return f, g
        else:
            return K.one, K.one, f, g

    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:
        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 multout:
        return cp, cq, p, q

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

    return p, q

def dmp_mul_term(f, c, i, u, K):
    """Multiply `f` by `c(x_2..x_u)*x_0**i` in `K[X]`. """
    if not u:
        return dup_mul_term(f, c, i, K)

    v = u-1

    if dmp_zero_p(f, u):
        return f
    if dmp_zero_p(c, v):
        return dmp_zero(u)
    else:
        return [ dmp_mul(cf, c, v, K) for cf in f ] + dmp_zeros(i, v, K)

def dmp_zz_wang_hensel_lifting(f, H, LC, A, p, u, K):
    """Wang/EEZ: Parallel Hensel lifting algorithm. """
    S, n, v = [f], len(A), u-1

    H = list(H)

    for i, a in enumerate(reversed(A[1:])):
        s = dmp_eval_in(S[0], a, n-i, u-i, K)
        S.insert(0, dmp_ground_trunc(s, p, v-i, K))

    d = max(dmp_degree_list(f, u)[1:])

    for j, s, a in zip(xrange(2, n+2), S, A):
        G, w = list(H), j-1

        I, J = A[:j-2], A[j-1:]

        for i, (h, lc) in enumerate(zip(H, LC)):
            lc = dmp_ground_trunc(dmp_eval_tail(lc, J, v, K), p, w-1, K)
            H[i] = [lc] + dmp_raise(h[1:], 1, w-1, K)

        m = dmp_nest([K.one, -a], w, K)
        M = dmp_one(w, K)

        c = dmp_sub(s, dmp_expand(H, w, K), w, K)

        dj = dmp_degree_in(s, w, w)

        for k in xrange(0, dj):
            if dmp_zero_p(c, w):
                break

            M = dmp_mul(M, m, w, K)
            C = dmp_diff_eval_in(c, k+1, a, w, w, K)

            if not dmp_zero_p(C, w-1):
                C = dmp_quo_ground(C, K.factorial(k+1), w-1, K)
                T = dmp_zz_diophantine(G, C, I, d, p, w-1, K)

                for i, (h, t) in enumerate(zip(H, T)):
                    h = dmp_add_mul(h, dmp_raise(t, 1, w-1, K), M, w, K)
                    H[i] = dmp_ground_trunc(h, p, w, K)

                h = dmp_sub(s, dmp_expand(H, w, K), w, K)
                c = dmp_ground_trunc(h, p, w, K)

    if dmp_expand(H, u, K) != f:
        raise ExtraneousFactors # pragma: no cover
    else:
        return H

def _dmp_ff_trivial_gcd(f, g, u, K):
    """Handle trivial cases in GCD algorithm over a field. """
    zero_f = dmp_zero_p(f, u)
    zero_g = dmp_zero_p(g, u)

    if zero_f and zero_g:
        return tuple(dmp_zeros(3, u, K))
    elif zero_f:
        return (dmp_ground_monic(g, u, K), dmp_zero(u), dmp_ground(dmp_ground_LC(g, u, K), u))
    elif zero_g:
        return (dmp_ground_monic(f, u, K), dmp_ground(dmp_ground_LC(f, u, K), u), dmp_zero(u))
    elif query("USE_SIMPLIFY_GCD"):
        return _dmp_simplify_gcd(f, g, u, K)
    else:
        return None

def dmp_exquo(f, g, u, K):
    """
    Returns polynomial quotient in ``K[X]``.

    **Examples**

    >>> from sympy.polys.domains import ZZ
    >>> from sympy.polys.densearith import dmp_exquo

    >>> f = ZZ.map([[1], [1, 0], []])
    >>> g = ZZ.map([[1], [1, 0]])
    >>> h = ZZ.map([[2], [2]])

    >>> dmp_exquo(f, g, 1, ZZ)
    [[1], []]

    >>> dmp_exquo(f, h, 1, ZZ)
    Traceback (most recent call last):
    ...
    ExactQuotientFailed: [[2], [2]] does not divide [[1], [1, 0], []]

    """
    q, r = dmp_div(f, g, u, K)

    if dmp_zero_p(r, u):
        return q
    else:
        raise ExactQuotientFailed(f, g)

def dmp_add_term(f, c, i, u, K):
    """
    Add ``c(x_2..x_u)*x_0**i`` to ``f`` in ``K[X]``.

    **Examples**

    >>> from sympy.polys.domains import ZZ
    >>> from sympy.polys.densearith import dmp_add_term

    >>> f = ZZ.map([[1, 0], [1]])
    >>> c = ZZ.map([2])

    >>> dmp_add_term(f, c, 2, 1, ZZ)
    [[2], [1, 0], [1]]

    """
    if not u:
        return dup_add_term(f, c, i, K)

    v = u-1

    if dmp_zero_p(c, v):
        return f

    n = len(f)
    m = n-i-1

    if i == n-1:
        return dmp_strip([dmp_add(f[0], c, v, K)] + f[1:], u)
    else:
        if i >= n:
            return [c] + dmp_zeros(i-n, v, K) + f
        else:
            return f[:m] + [dmp_add(f[m], c, v, K)] + f[m+1:]

def dmp_pow(f, n, u, K):
    """Raise f to the n-th power in `K[X]`. """
    if not u:
        return dup_pow(f, n, K)

    if not n:
        return dmp_one(u, K)
    if n < 0:
        raise ValueError("can't raise polynomial to a negative power")
    if n == 1 or dmp_zero_p(f, u) or dmp_one_p(f, u, K):
        return f

    g = dmp_one(u, K)

    while True:
        n, m = n//2, n

        if m & 1:
            g = dmp_mul(g, f, u, K)

            if not n:
                break

        f = dmp_sqr(f, u, K)

    return g

def dmp_sqf_part(f, u, K):
    """
    Returns square-free part of a polynomial in ``K[X]``.

    Examples
    ========

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

    >>> R.dmp_sqf_part(x**3 + 2*x**2*y + x*y**2)
    x**2 + x*y

    """
    if not u:
        return dup_sqf_part(f, K)

    if K.is_FiniteField:
        return dmp_gf_sqf_part(f, u, K)

    if dmp_zero_p(f, u):
        return f

    if K.is_negative(dmp_ground_LC(f, u, K)):
        f = dmp_neg(f, u, K)

    gcd = dmp_gcd(f, dmp_diff(f, 1, u, K), u, K)
    sqf = dmp_quo(f, gcd, u, K)

    if K.has_Field:
        return dmp_ground_monic(sqf, u, K)
    else:
        return dmp_ground_primitive(sqf, u, K)[1]

def dmp_content(f, u, K):
    """
    Returns GCD of multivariate coefficients.

    Examples
    ========

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

    >>> R.dmp_content(2*x*y + 6*x + 4*y + 12)
    2*y + 6

    """
    cont, v = dmp_LC(f, K), u - 1

    if dmp_zero_p(f, u):
        return cont

    for c in f[1:]:
        cont = dmp_gcd(cont, c, v, K)

        if dmp_one_p(cont, v, K):
            break

    if K.is_negative(dmp_ground_LC(cont, v, K)):
        return dmp_neg(cont, v, K)
    else:
        return cont

def dmp_ground_primitive(f, u, K):
    """
    Compute content and the primitive form of ``f`` in ``K[X]``.

    Examples
    ========

    >>> from sympy.polys import ring, ZZ, QQ

    >>> R, x,y = ring("x,y", ZZ)
    >>> f = 2*x*y + 6*x + 4*y + 12

    >>> R.dmp_ground_primitive(f)
    (2, x*y + 3*x + 2*y + 6)

    >>> R, x,y = ring("x,y", QQ)
    >>> f = 2*x*y + 6*x + 4*y + 12

    >>> R.dmp_ground_primitive(f)
    (2, x*y + 3*x + 2*y + 6)

    """
    if not u:
        return dup_primitive(f, K)

    if dmp_zero_p(f, u):
        return K.zero, f

    cont = dmp_ground_content(f, u, K)

    if K.is_one(cont):
        return cont, f
    else:
        return cont, dmp_quo_ground(f, cont, u, K)

def dmp_compose(f, g, u, K):
    """
    Evaluate functional composition ``f(g)`` in ``K[X]``.

    Examples
    ========

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

    >>> R.dmp_compose(x*y + 2*x + y, y)
    y**2 + 3*y

    """
    if not u:
        return dup_compose(f, g, K)

    if dmp_zero_p(f, u):
        return f

    h = [f[0]]

    for c in f[1:]:
        h = dmp_mul(h, g, u, K)
        h = dmp_add_term(h, c, 0, u, K)

    return h

def dmp_exquo(f, g, u, K):
    """
    Returns polynomial quotient in ``K[X]``.

    Examples
    ========

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

    >>> f = x**2 + x*y
    >>> g = x + y
    >>> h = 2*x + 2

    >>> R.dmp_exquo(f, g)
    x

    >>> R.dmp_exquo(f, h)
    Traceback (most recent call last):
    ...
    ExactQuotientFailed: [[2], [2]] does not divide [[1], [1, 0], []]

    """
    q, r = dmp_div(f, g, u, K)

    if dmp_zero_p(r, u):
        return q
    else:
        raise ExactQuotientFailed(f, g)

def dmp_content(f, u, K):
    """
    Returns GCD of multivariate coefficients.

    **Examples**

    >>> from sympy.polys.domains import ZZ
    >>> from sympy.polys.euclidtools import dmp_content

    >>> f = ZZ.map([[2, 6], [4, 12]])

    >>> dmp_content(f, 1, ZZ)
    [2, 6]

    """
    cont, v = dmp_LC(f, K), u-1

    if dmp_zero_p(f, u):
        return cont

    for c in f[1:]:
        cont = dmp_gcd(cont, c, v, K)

        if dmp_one_p(cont, v, K):
            break

    if K.is_negative(dmp_ground_LC(cont, v, K)):
        return dmp_neg(cont, v, K)
    else:
        return cont