Python iterables.subsets函数代码示例

def test_issue_11230():
    # a specific test that always failed
    a, b, f, k, l, i = symbols('a b f k l i')
    p = [a*b*f*k*l, a*i*k**2*l, f*i*k**2*l]
    R, C = cse(p)
    assert not any(i.is_Mul for a in C for i in a.args)

    # random tests for the issue
    from random import choice
    from sympy.core.function import expand_mul
    s = symbols('a:m')
    # 35 Mul tests, none of which should ever fail
    ex = [Mul(*[choice(s) for i in range(5)]) for i in range(7)]
    for p in subsets(ex, 3):
        p = list(p)
        R, C = cse(p)
        assert not any(i.is_Mul for a in C for i in a.args)
        for ri in reversed(R):
            for i in range(len(C)):
                C[i] = C[i].subs(*ri)
        assert p == C
    # 35 Add tests, none of which should ever fail
    ex = [Add(*[choice(s[:7]) for i in range(5)]) for i in range(7)]
    for p in subsets(ex, 3):
        p = list(p)
        was = R, C = cse(p)
        assert not any(i.is_Add for a in C for i in a.args)
        for ri in reversed(R):
            for i in range(len(C)):
                C[i] = C[i].subs(*ri)
        # use expand_mul to handle cases like this:
        # p = [a + 2*b + 2*e, 2*b + c + 2*e, b + 2*c + 2*g]
        # x0 = 2*(b + e) is identified giving a rebuilt p that
        # is now `[a + 2*(b + e), c + 2*(b + e), b + 2*c + 2*g]`
        assert p == [expand_mul(i) for i in C]

def test_issue2300():
    args = [x, y, S(2), S.Half]
    def ok(a):
        """Return True if the input args for diff are ok"""
        if not a: return False
        if a[0].is_Symbol is False: return False
        s_at = [i for i in range(len(a)) if a[i].is_Symbol]
        n_at = [i for i in range(len(a)) if not a[i].is_Symbol]
        # every symbol is followed by symbol or int
        # every number is followed by a symbol
        return (all([a[i+1].is_Symbol or a[i+1].is_Integer
            for i in s_at if i+1<len(a)]) and
            all([a[i+1].is_Symbol
            for i in n_at if i+1<len(a)]))
    eq = x**10*y**8
    for a in subsets(args):
        for v in variations(a, len(a)):
            if ok(v):
                noraise = eq.diff(*v)
            else:
                raises(ValueError, 'eq.diff(*v)')

def pairwise_most_common(sets):
    """Return a list of `(s, L)` tuples where `s` is the largest subset
    of elements that appear in pairs of sets given by `sets` and `L`
    is a list of tuples giving the indices of the pairs of sets in
    which those elements appeared. All `s` will be of the same length.

    Examples
    ========

    >>> from sympy.simplify.cse_main import pairwise_most_common
    >>> pairwise_most_common((
    ...     {1,2,3},
    ...     {1,3,5},
    ...     {1,2,3,4,5},
    ...     {1,2,3,6}))
    [({1, 3, 5}, [(1, 2)]), ({1, 2, 3}, [(0, 2), (0, 3), (2, 3)])]
    >>>
    """
    from sympy.utilities.iterables import subsets
    from collections import defaultdict
    most = -1
    for i, j in subsets(list(range(len(sets))), 2):
        com = sets[i] & sets[j]
        if com and len(com) > most:
            best = defaultdict(list)
            best_keys = []
            most = len(com)
        if len(com) == most:
            if com not in best_keys:
                best_keys.append(com)
            best[best_keys.index(com)].append((i,j))
    if most == -1:
        return []
    for k in range(len(best)):
        best_keys[k] = (best_keys[k], best[k])
    best_keys.sort(key=lambda x: len(x[1]))
    return best_keys

def test_farthest_points_closest_points():
    from random import randint
    from sympy.utilities.iterables import subsets

    for how in (min, max):
        if how is min:
            func = closest_points
        else:
            func = farthest_points

        raises(ValueError, lambda: func(Point2D(0, 0), Point2D(0, 0)))

        # 3rd pt dx is close and pt is closer to 1st pt
        p1 = [Point2D(0, 0), Point2D(3, 0), Point2D(1, 1)]
        # 3rd pt dx is close and pt is closer to 2nd pt
        p2 = [Point2D(0, 0), Point2D(3, 0), Point2D(2, 1)]
        # 3rd pt dx is close and but pt is not closer
        p3 = [Point2D(0, 0), Point2D(3, 0), Point2D(1, 10)]
        # 3rd pt dx is not closer and it's closer to 2nd pt
        p4 = [Point2D(0, 0), Point2D(3, 0), Point2D(4, 0)]
        # 3rd pt dx is not closer and it's closer to 1st pt
        p5 = [Point2D(0, 0), Point2D(3, 0), Point2D(-1, 0)]
        # duplicate point doesn't affect outcome
        dup = [Point2D(0, 0), Point2D(3, 0), Point2D(3, 0), Point2D(-1, 0)]
        # symbolic
        x = Symbol('x', positive=True)
        s = [Point2D(a) for a in ((x, 1), (x + 3, 2), (x + 2, 2))]

        for points in (p1, p2, p3, p4, p5, s, dup):
            d = how(i.distance(j) for i, j in subsets(points, 2))
            ans = a, b = list(func(*points))[0]
            a.distance(b) == d
            assert ans == _ordered_points(ans)

        # if the following ever fails, the above tests were not sufficient
        # and the logical error in the routine should be fixed
        points = set()
        while len(points) != 7:
            points.add(Point2D(randint(1, 100), randint(1, 100)))
        points = list(points)
        d = how(i.distance(j) for i, j in subsets(points, 2))
        ans = a, b = list(func(*points))[0]
        a.distance(b) == d
        assert ans == _ordered_points(ans)

    # equidistant points
    a, b, c = (
        Point2D(0, 0), Point2D(1, 0), Point2D(S(1)/2, sqrt(3)/2))
    ans = set([_ordered_points((i, j))
        for i, j in subsets((a, b, c), 2)])
    assert closest_points(b, c, a) == ans
    assert farthest_points(b, c, a) == ans

    # unique to farthest
    points = [(1, 1), (1, 2), (3, 1), (-5, 2), (15, 4)]
    assert farthest_points(*points) == set(
        [(Point2D(-5, 2), Point2D(15, 4))])
    points = [(1, -1), (1, -2), (3, -1), (-5, -2), (15, -4)]
    assert farthest_points(*points) == set(
        [(Point2D(-5, -2), Point2D(15, -4))])
    assert farthest_points((1, 1), (0, 0)) == set(
        [(Point2D(0, 0), Point2D(1, 1))])
    raises(ValueError, lambda: farthest_points((1, 1)))

def test_subsets():
    # combinations
    assert list(subsets([1, 2, 3], 0)) == [()]
    assert list(subsets([1, 2, 3], 1)) == [(1,), (2,), (3,)]
    assert list(subsets([1, 2, 3], 2)) == [(1, 2), (1, 3), (2, 3)]
    assert list(subsets([1, 2, 3], 3)) == [(1, 2, 3)]
    l = range(4)
    assert list(subsets(l, 0, repetition=True)) == [()]
    assert list(subsets(l, 1, repetition=True)) == [(0,), (1,), (2,), (3,)]
    assert list(subsets(l, 2, repetition=True)) == [(0, 0), (0, 1), (0, 2),
                                                    (0, 3), (1, 1), (1, 2),
                                                    (1, 3), (2, 2), (2, 3),
                                                    (3, 3)]
    assert list(subsets(l, 3, repetition=True)) == [(0, 0, 0), (0, 0, 1),
                                                    (0, 0, 2), (0, 0, 3),
                                                    (0, 1, 1), (0, 1, 2),
                                                    (0, 1, 3), (0, 2, 2),
                                                    (0, 2, 3), (0, 3, 3),
                                                    (1, 1, 1), (1, 1, 2),
                                                    (1, 1, 3), (1, 2, 2),
                                                    (1, 2, 3), (1, 3, 3),
                                                    (2, 2, 2), (2, 2, 3),
                                                    (2, 3, 3), (3, 3, 3)]
    assert len(list(subsets(l, 4, repetition=True))) == 35

    assert list(subsets(l[:2], 3, repetition=False)) == []
    assert list(subsets(l[:2], 3, repetition=True)) == [(0, 0, 0),
                                                        (0, 0, 1),
                                                        (0, 1, 1),
                                                        (1, 1, 1)]
    assert list(subsets([1, 2], repetition=True)) == \
        [(), (1,), (2,), (1, 1), (1, 2), (2, 2)]
    assert list(subsets([1, 2], repetition=False)) == \
        [(), (1,), (2,), (1, 2)]
    assert list(subsets([1, 2, 3], 2)) == \
        [(1, 2), (1, 3), (2, 3)]
    assert list(subsets([1, 2, 3], 2, repetition=True)) == \
        [(1, 1), (1, 2), (1, 3), (2, 2), (2, 3), (3, 3)]

 def delta(p):
     if len(p) == 1:
         return oo
     return min(abs(i[0] - i[1]) for i in subsets(p, 2))

def test_subsets():
    # combinations
    assert list(subsets([1, 2, 3], 0)) == [[]]
    assert list(subsets([1, 2, 3], 1)) == [[1], [2], [3]]
    assert list(subsets([1, 2, 3], 2)) == [[1, 2], [1,3], [2, 3]]
    assert list(subsets([1, 2, 3], 3)) == [[1, 2, 3]]
    l = range(4)
    assert list(subsets(l, 0, repetition=True)) == [[]]
    assert list(subsets(l, 1, repetition=True)) == [[0], [1], [2], [3]]
    assert list(subsets(l, 2, repetition=True)) == [[0, 0], [0, 1], [0, 2],
                                                    [0, 3], [1, 1], [1, 2],
                                                    [1, 3], [2, 2], [2, 3],
                                                    [3, 3]]
    assert list(subsets(l, 3, repetition=True)) == [[0, 0, 0], [0, 0, 1],
                                                    [0, 0, 2], [0, 0, 3],
                                                    [0, 1, 1], [0, 1, 2],
                                                    [0, 1, 3], [0, 2, 2],
                                                    [0, 2, 3], [0, 3, 3],
                                                    [1, 1, 1], [1, 1, 2],
                                                    [1, 1, 3], [1, 2, 2],
                                                    [1, 2, 3], [1, 3, 3],
                                                    [2, 2, 2], [2, 2, 3],
                                                    [2, 3, 3], [3, 3, 3]]
    assert len(list(subsets(l, 4, repetition=True))) == 35

    assert list(subsets(l[:2], 3, repetition=False)) == []
    assert list(subsets(l[:2], 3, repetition=True)) == [[0, 0, 0],
                                                        [0, 0, 1],
                                                        [0, 1, 1],
                                                        [1, 1, 1]]
    assert list(subsets([1, 2], repetition=True)) == \
           [[], [1], [2], [1, 1], [1, 2], [2, 2]]
    assert list(subsets([1, 2], repetition=False)) == \
           [[], [1], [2], [1, 2]]
    assert list(subsets([1, 2, 3], 2)) == \
           [[1, 2], [1, 3], [2, 3]]
    assert list(subsets([1, 2, 3], 2, repetition=True)) == \
           [[1, 1], [1, 2], [1, 3], [2, 2], [2, 3], [3, 3]]

def test_arguments():
    """Functions accepting `Point` objects in `geometry`
    should also accept tuples and lists and
    automatically convert them to points."""

    singles2d = ((1,2), [1,2], Point(1,2))
    singles2d2 = ((1,3), [1,3], Point(1,3))
    doubles2d = cartes(singles2d, singles2d2)
    p2d = Point2D(1,2)
    singles3d = ((1,2,3), [1,2,3], Point(1,2,3))
    doubles3d = subsets(singles3d, 2)
    p3d = Point3D(1,2,3)
    singles4d = ((1,2,3,4), [1,2,3,4], Point(1,2,3,4))
    doubles4d = subsets(singles4d, 2)
    p4d = Point(1,2,3,4)

    # test 2D
    test_single = ['distance', 'is_scalar_multiple', 'taxicab_distance', 'midpoint', 'intersection', 'dot', 'equals', '__add__', '__sub__']
    test_double = ['is_concyclic', 'is_collinear']
    for p in singles2d:
        Point2D(p)
    for func in test_single:
        for p in singles2d:
            getattr(p2d, func)(p)
    for func in test_double:
        for p in doubles2d:
            getattr(p2d, func)(*p)

    # test 3D
    test_double = ['is_collinear']
    for p in singles3d:
        Point3D(p)
    for func in test_single:
        for p in singles3d:
            getattr(p3d, func)(p)
    for func in test_double:
        for p in doubles2d:
            getattr(p3d, func)(*p)

    # test 4D
    test_double = ['is_collinear']
    for p in singles4d:
        Point(p)
    for func in test_single:
        for p in singles4d:
            getattr(p4d, func)(p)
    for func in test_double:
        for p in doubles4d:
            getattr(p4d, func)(*p)

    # test evaluate=False for ops
    x = Symbol('x')
    a = Point(0, 1)
    assert a + (0.1, x) == Point(0.1, 1 + x)
    a = Point(0, 1)
    assert a/10.0 == Point(0.0, 0.1)
    a = Point(0, 1)
    assert a*10.0 == Point(0.0, 10.0)

    # test evaluate=False when changing dimensions
    u = Point(.1, .2, evaluate=False)
    u4 = Point(u, dim=4, on_morph='ignore')
    assert u4.args == (.1, .2, 0, 0)
    assert all(i.is_Float for i in u4.args[:2])
    # and even when *not* changing dimensions
    assert all(i.is_Float for i in Point(u).args)

    # never raise error if creating an origin
    assert Point(dim=3, on_morph='error')

#.........这里部分代码省略.........
            return d

        def from_dict(d):
            # build expression from dict from
            # as_coefficients_dict or as_powers_dict
            # SHARES F
            return ufunc(*[F(k, v) for k, v in d.items()])

        def update(k):
            # updates all of the info associated with k using
            # the com_dict: func_dicts, func_args, opt_subs
            # returns True if all values were updated, else None
            # SHARES com_dict, com_func, func_dicts, func_args,
            #        opt_subs, funcs, verbose
            for di in com_dict:
                # don't allow a sign to change
                if com_dict[di] > func_dicts[k][di]:
                    return
            # remove it
            if Func is Add:
                take = min(func_dicts[k][i] for i in com_dict)
                com_func_take = Mul(take, from_dict(com_dict), evaluate=False)
            else:
                take = igcd(*[func_dicts[k][i] for i in com_dict])
                com_func_take = Pow(from_dict(com_dict), take, evaluate=False)
            for di in com_dict:
                func_dicts[k][di] -= take*com_dict[di]
            # compute the remaining expression
            rem = from_dict(func_dicts[k])
            # reject hollow change, e.g extracting x + 1 from x + 3
            if Func is Add and rem and rem.is_Integer and 1 in com_dict:
                return
            if verbose:
                print('\nfunc %s (%s) \ncontains %s \nas %s \nleaving %s' %
                    (funcs[k], func_dicts[k], com_func, com_func_take, rem))
            # recompute the dict since some keys may now
            # have corresponding values of 0; one could
            # keep track of which ones went to zero but
            # this seems cleaner
            func_dicts[k] = as_dict(rem)
            # update associated info
            func_dicts[k][com_func] = take
            func_args[k] = set(func_dicts[k])
            # keep the constant separate from the remaining
            # part of the expression, e.g. 2*(a*b) rather than 2*a*b
            opt_subs[funcs[k]] = ufunc(rem, com_func_take)
            # everything was updated
            return True

        def get_copy(i):
            return [func_dicts[i].copy(), func_args[i].copy(), funcs[i], i]

        def restore(dafi):
            i = dafi.pop()
            func_dicts[i], func_args[i], funcs[i] = dafi

        # ----------------- end helpers -----------------------

        func_dicts = [as_dict(f) for f in funcs]
        func_args = [set(d) for d in func_dicts]
        while True:
            hit = pairwise_most_common(func_args)
            if not hit or len(hit[0][0]) <= 1:
                break
            changed = False
            for com_args, ij in hit:
                take = len(com_args)
                ALL = list(ordered(com_args))
                while take >= 2:
                    for com_args in subsets(ALL, take):
                        com_func = Func(*com_args)
                        com_dict = as_dict(com_func)
                        for i, j in ij:
                            dafi = None
                            if com_func != funcs[i]:
                                dafi = get_copy(i)
                                ch = update(i)
                                if not ch:
                                    restore(dafi)
                                    continue
                            if com_func != funcs[j]:
                                dafj = get_copy(j)
                                ch = update(j)
                                if not ch:
                                    if dafi is not None:
                                        restore(dafi)
                                    restore(dafj)
                                    continue
                            changed = True
                        if changed:
                            break
                    else:
                        take -= 1
                        continue
                    break
                else:
                    continue
                break
            if not changed:
                break

def test_subsets():
    assert list(subsets([1, 2, 3], 1)) == [[1], [2], [3]]
    assert list(subsets([1, 2, 3], 2)) == [[1, 2], [1,3], [2, 3]]
    assert list(subsets([1, 2, 3], 3)) == [[1, 2, 3]]

def zzx_zassenhaus(f):
    """Factor square-free polynomials over Z[x]. """
    n = zzx_degree(f)

    if n == 1:
        return [f]

    A = zzx_max_norm(f)
    b = zzx_LC(f)
    B = abs(int(sqrt(n+1)*2**n*A*b))
    C = (n+1)**(2*n)*A**(2*n-1)
    gamma = int(ceil(2*log(C, 2)))
    prime_max = int(2*gamma*log(gamma))

    for p in xrange(3, prime_max+1):
        if not isprime(p) or b % p == 0:
            continue

        F = gf_from_int_poly(f, p)

        if gf_sqf_p(F, p):
            break

    l = int(ceil(log(2*B + 1, p)))

    modular = []

    for ff in gf_factor_sqf(F, p)[1]:
        modular.append(gf_to_int_poly(ff, p))

    g = zzx_hensel_lift(p, f, modular, l)

    T = set(range(len(g)))
    factors, s = [], 1

    while 2*s <= len(T):
        for S in subsets(T, s):
            G, H = [b], [b]

            S = set(S)

            for i in S:
                G = zzx_mul(G, g[i])
            for i in T-S:
                H = zzx_mul(H, g[i])

            G = zzx_trunc(G, p**l)
            H = zzx_trunc(H, p**l)

            G_norm = zzx_l1_norm(G)
            H_norm = zzx_l1_norm(H)

            if G_norm*H_norm <= B:
                T = T - S

                G = zzx_primitive(G)[1]
                f = zzx_primitive(H)[1]

                factors.append(G)
                b = zzx_LC(f)

                break
        else:
            s += 1

    return factors + [f]