ai-content-maker/.venv/Lib/site-packages/sympy/combinatorics/tests/test_permutations.py

563 lines
20 KiB
Python

from itertools import permutations
from sympy.core.expr import unchanged
from sympy.core.numbers import Integer
from sympy.core.relational import Eq
from sympy.core.symbol import Symbol
from sympy.core.singleton import S
from sympy.combinatorics.permutations import \
Permutation, _af_parity, _af_rmul, _af_rmuln, AppliedPermutation, Cycle
from sympy.printing import sstr, srepr, pretty, latex
from sympy.testing.pytest import raises, warns_deprecated_sympy
rmul = Permutation.rmul
a = Symbol('a', integer=True)
def test_Permutation():
# don't auto fill 0
raises(ValueError, lambda: Permutation([1]))
p = Permutation([0, 1, 2, 3])
# call as bijective
assert [p(i) for i in range(p.size)] == list(p)
# call as operator
assert p(list(range(p.size))) == list(p)
# call as function
assert list(p(1, 2)) == [0, 2, 1, 3]
raises(TypeError, lambda: p(-1))
raises(TypeError, lambda: p(5))
# conversion to list
assert list(p) == list(range(4))
assert Permutation(size=4) == Permutation(3)
assert Permutation(Permutation(3), size=5) == Permutation(4)
# cycle form with size
assert Permutation([[1, 2]], size=4) == Permutation([[1, 2], [0], [3]])
# random generation
assert Permutation.random(2) in (Permutation([1, 0]), Permutation([0, 1]))
p = Permutation([2, 5, 1, 6, 3, 0, 4])
q = Permutation([[1], [0, 3, 5, 6, 2, 4]])
assert len({p, p}) == 1
r = Permutation([1, 3, 2, 0, 4, 6, 5])
ans = Permutation(_af_rmuln(*[w.array_form for w in (p, q, r)])).array_form
assert rmul(p, q, r).array_form == ans
# make sure no other permutation of p, q, r could have given
# that answer
for a, b, c in permutations((p, q, r)):
if (a, b, c) == (p, q, r):
continue
assert rmul(a, b, c).array_form != ans
assert p.support() == list(range(7))
assert q.support() == [0, 2, 3, 4, 5, 6]
assert Permutation(p.cyclic_form).array_form == p.array_form
assert p.cardinality == 5040
assert q.cardinality == 5040
assert q.cycles == 2
assert rmul(q, p) == Permutation([4, 6, 1, 2, 5, 3, 0])
assert rmul(p, q) == Permutation([6, 5, 3, 0, 2, 4, 1])
assert _af_rmul(p.array_form, q.array_form) == \
[6, 5, 3, 0, 2, 4, 1]
assert rmul(Permutation([[1, 2, 3], [0, 4]]),
Permutation([[1, 2, 4], [0], [3]])).cyclic_form == \
[[0, 4, 2], [1, 3]]
assert q.array_form == [3, 1, 4, 5, 0, 6, 2]
assert q.cyclic_form == [[0, 3, 5, 6, 2, 4]]
assert q.full_cyclic_form == [[0, 3, 5, 6, 2, 4], [1]]
assert p.cyclic_form == [[0, 2, 1, 5], [3, 6, 4]]
t = p.transpositions()
assert t == [(0, 5), (0, 1), (0, 2), (3, 4), (3, 6)]
assert Permutation.rmul(*[Permutation(Cycle(*ti)) for ti in (t)])
assert Permutation([1, 0]).transpositions() == [(0, 1)]
assert p**13 == p
assert q**0 == Permutation(list(range(q.size)))
assert q**-2 == ~q**2
assert q**2 == Permutation([5, 1, 0, 6, 3, 2, 4])
assert q**3 == q**2*q
assert q**4 == q**2*q**2
a = Permutation(1, 3)
b = Permutation(2, 0, 3)
I = Permutation(3)
assert ~a == a**-1
assert a*~a == I
assert a*b**-1 == a*~b
ans = Permutation(0, 5, 3, 1, 6)(2, 4)
assert (p + q.rank()).rank() == ans.rank()
assert (p + q.rank())._rank == ans.rank()
assert (q + p.rank()).rank() == ans.rank()
raises(TypeError, lambda: p + Permutation(list(range(10))))
assert (p - q.rank()).rank() == Permutation(0, 6, 3, 1, 2, 5, 4).rank()
assert p.rank() - q.rank() < 0 # for coverage: make sure mod is used
assert (q - p.rank()).rank() == Permutation(1, 4, 6, 2)(3, 5).rank()
assert p*q == Permutation(_af_rmuln(*[list(w) for w in (q, p)]))
assert p*Permutation([]) == p
assert Permutation([])*p == p
assert p*Permutation([[0, 1]]) == Permutation([2, 5, 0, 6, 3, 1, 4])
assert Permutation([[0, 1]])*p == Permutation([5, 2, 1, 6, 3, 0, 4])
pq = p ^ q
assert pq == Permutation([5, 6, 0, 4, 1, 2, 3])
assert pq == rmul(q, p, ~q)
qp = q ^ p
assert qp == Permutation([4, 3, 6, 2, 1, 5, 0])
assert qp == rmul(p, q, ~p)
raises(ValueError, lambda: p ^ Permutation([]))
assert p.commutator(q) == Permutation(0, 1, 3, 4, 6, 5, 2)
assert q.commutator(p) == Permutation(0, 2, 5, 6, 4, 3, 1)
assert p.commutator(q) == ~q.commutator(p)
raises(ValueError, lambda: p.commutator(Permutation([])))
assert len(p.atoms()) == 7
assert q.atoms() == {0, 1, 2, 3, 4, 5, 6}
assert p.inversion_vector() == [2, 4, 1, 3, 1, 0]
assert q.inversion_vector() == [3, 1, 2, 2, 0, 1]
assert Permutation.from_inversion_vector(p.inversion_vector()) == p
assert Permutation.from_inversion_vector(q.inversion_vector()).array_form\
== q.array_form
raises(ValueError, lambda: Permutation.from_inversion_vector([0, 2]))
assert Permutation(list(range(500, -1, -1))).inversions() == 125250
s = Permutation([0, 4, 1, 3, 2])
assert s.parity() == 0
_ = s.cyclic_form # needed to create a value for _cyclic_form
assert len(s._cyclic_form) != s.size and s.parity() == 0
assert not s.is_odd
assert s.is_even
assert Permutation([0, 1, 4, 3, 2]).parity() == 1
assert _af_parity([0, 4, 1, 3, 2]) == 0
assert _af_parity([0, 1, 4, 3, 2]) == 1
s = Permutation([0])
assert s.is_Singleton
assert Permutation([]).is_Empty
r = Permutation([3, 2, 1, 0])
assert (r**2).is_Identity
assert rmul(~p, p).is_Identity
assert (~p)**13 == Permutation([5, 2, 0, 4, 6, 1, 3])
assert ~(r**2).is_Identity
assert p.max() == 6
assert p.min() == 0
q = Permutation([[6], [5], [0, 1, 2, 3, 4]])
assert q.max() == 4
assert q.min() == 0
p = Permutation([1, 5, 2, 0, 3, 6, 4])
q = Permutation([[1, 2, 3, 5, 6], [0, 4]])
assert p.ascents() == [0, 3, 4]
assert q.ascents() == [1, 2, 4]
assert r.ascents() == []
assert p.descents() == [1, 2, 5]
assert q.descents() == [0, 3, 5]
assert Permutation(r.descents()).is_Identity
assert p.inversions() == 7
# test the merge-sort with a longer permutation
big = list(p) + list(range(p.max() + 1, p.max() + 130))
assert Permutation(big).inversions() == 7
assert p.signature() == -1
assert q.inversions() == 11
assert q.signature() == -1
assert rmul(p, ~p).inversions() == 0
assert rmul(p, ~p).signature() == 1
assert p.order() == 6
assert q.order() == 10
assert (p**(p.order())).is_Identity
assert p.length() == 6
assert q.length() == 7
assert r.length() == 4
assert p.runs() == [[1, 5], [2], [0, 3, 6], [4]]
assert q.runs() == [[4], [2, 3, 5], [0, 6], [1]]
assert r.runs() == [[3], [2], [1], [0]]
assert p.index() == 8
assert q.index() == 8
assert r.index() == 3
assert p.get_precedence_distance(q) == q.get_precedence_distance(p)
assert p.get_adjacency_distance(q) == p.get_adjacency_distance(q)
assert p.get_positional_distance(q) == p.get_positional_distance(q)
p = Permutation([0, 1, 2, 3])
q = Permutation([3, 2, 1, 0])
assert p.get_precedence_distance(q) == 6
assert p.get_adjacency_distance(q) == 3
assert p.get_positional_distance(q) == 8
p = Permutation([0, 3, 1, 2, 4])
q = Permutation.josephus(4, 5, 2)
assert p.get_adjacency_distance(q) == 3
raises(ValueError, lambda: p.get_adjacency_distance(Permutation([])))
raises(ValueError, lambda: p.get_positional_distance(Permutation([])))
raises(ValueError, lambda: p.get_precedence_distance(Permutation([])))
a = [Permutation.unrank_nonlex(4, i) for i in range(5)]
iden = Permutation([0, 1, 2, 3])
for i in range(5):
for j in range(i + 1, 5):
assert a[i].commutes_with(a[j]) == \
(rmul(a[i], a[j]) == rmul(a[j], a[i]))
if a[i].commutes_with(a[j]):
assert a[i].commutator(a[j]) == iden
assert a[j].commutator(a[i]) == iden
a = Permutation(3)
b = Permutation(0, 6, 3)(1, 2)
assert a.cycle_structure == {1: 4}
assert b.cycle_structure == {2: 1, 3: 1, 1: 2}
# issue 11130
raises(ValueError, lambda: Permutation(3, size=3))
raises(ValueError, lambda: Permutation([1, 2, 0, 3], size=3))
def test_Permutation_subclassing():
# Subclass that adds permutation application on iterables
class CustomPermutation(Permutation):
def __call__(self, *i):
try:
return super().__call__(*i)
except TypeError:
pass
try:
perm_obj = i[0]
return [self._array_form[j] for j in perm_obj]
except TypeError:
raise TypeError('unrecognized argument')
def __eq__(self, other):
if isinstance(other, Permutation):
return self._hashable_content() == other._hashable_content()
else:
return super().__eq__(other)
def __hash__(self):
return super().__hash__()
p = CustomPermutation([1, 2, 3, 0])
q = Permutation([1, 2, 3, 0])
assert p == q
raises(TypeError, lambda: q([1, 2]))
assert [2, 3] == p([1, 2])
assert type(p * q) == CustomPermutation
assert type(q * p) == Permutation # True because q.__mul__(p) is called!
# Run all tests for the Permutation class also on the subclass
def wrapped_test_Permutation():
# Monkeypatch the class definition in the globals
globals()['__Perm'] = globals()['Permutation']
globals()['Permutation'] = CustomPermutation
test_Permutation()
globals()['Permutation'] = globals()['__Perm'] # Restore
del globals()['__Perm']
wrapped_test_Permutation()
def test_josephus():
assert Permutation.josephus(4, 6, 1) == Permutation([3, 1, 0, 2, 5, 4])
assert Permutation.josephus(1, 5, 1).is_Identity
def test_ranking():
assert Permutation.unrank_lex(5, 10).rank() == 10
p = Permutation.unrank_lex(15, 225)
assert p.rank() == 225
p1 = p.next_lex()
assert p1.rank() == 226
assert Permutation.unrank_lex(15, 225).rank() == 225
assert Permutation.unrank_lex(10, 0).is_Identity
p = Permutation.unrank_lex(4, 23)
assert p.rank() == 23
assert p.array_form == [3, 2, 1, 0]
assert p.next_lex() is None
p = Permutation([1, 5, 2, 0, 3, 6, 4])
q = Permutation([[1, 2, 3, 5, 6], [0, 4]])
a = [Permutation.unrank_trotterjohnson(4, i).array_form for i in range(5)]
assert a == [[0, 1, 2, 3], [0, 1, 3, 2], [0, 3, 1, 2], [3, 0, 1,
2], [3, 0, 2, 1] ]
assert [Permutation(pa).rank_trotterjohnson() for pa in a] == list(range(5))
assert Permutation([0, 1, 2, 3]).next_trotterjohnson() == \
Permutation([0, 1, 3, 2])
assert q.rank_trotterjohnson() == 2283
assert p.rank_trotterjohnson() == 3389
assert Permutation([1, 0]).rank_trotterjohnson() == 1
a = Permutation(list(range(3)))
b = a
l = []
tj = []
for i in range(6):
l.append(a)
tj.append(b)
a = a.next_lex()
b = b.next_trotterjohnson()
assert a == b is None
assert {tuple(a) for a in l} == {tuple(a) for a in tj}
p = Permutation([2, 5, 1, 6, 3, 0, 4])
q = Permutation([[6], [5], [0, 1, 2, 3, 4]])
assert p.rank() == 1964
assert q.rank() == 870
assert Permutation([]).rank_nonlex() == 0
prank = p.rank_nonlex()
assert prank == 1600
assert Permutation.unrank_nonlex(7, 1600) == p
qrank = q.rank_nonlex()
assert qrank == 41
assert Permutation.unrank_nonlex(7, 41) == Permutation(q.array_form)
a = [Permutation.unrank_nonlex(4, i).array_form for i in range(24)]
assert a == [
[1, 2, 3, 0], [3, 2, 0, 1], [1, 3, 0, 2], [1, 2, 0, 3], [2, 3, 1, 0],
[2, 0, 3, 1], [3, 0, 1, 2], [2, 0, 1, 3], [1, 3, 2, 0], [3, 0, 2, 1],
[1, 0, 3, 2], [1, 0, 2, 3], [2, 1, 3, 0], [2, 3, 0, 1], [3, 1, 0, 2],
[2, 1, 0, 3], [3, 2, 1, 0], [0, 2, 3, 1], [0, 3, 1, 2], [0, 2, 1, 3],
[3, 1, 2, 0], [0, 3, 2, 1], [0, 1, 3, 2], [0, 1, 2, 3]]
N = 10
p1 = Permutation(a[0])
for i in range(1, N+1):
p1 = p1*Permutation(a[i])
p2 = Permutation.rmul_with_af(*[Permutation(h) for h in a[N::-1]])
assert p1 == p2
ok = []
p = Permutation([1, 0])
for i in range(3):
ok.append(p.array_form)
p = p.next_nonlex()
if p is None:
ok.append(None)
break
assert ok == [[1, 0], [0, 1], None]
assert Permutation([3, 2, 0, 1]).next_nonlex() == Permutation([1, 3, 0, 2])
assert [Permutation(pa).rank_nonlex() for pa in a] == list(range(24))
def test_mul():
a, b = [0, 2, 1, 3], [0, 1, 3, 2]
assert _af_rmul(a, b) == [0, 2, 3, 1]
assert _af_rmuln(a, b, list(range(4))) == [0, 2, 3, 1]
assert rmul(Permutation(a), Permutation(b)).array_form == [0, 2, 3, 1]
a = Permutation([0, 2, 1, 3])
b = (0, 1, 3, 2)
c = (3, 1, 2, 0)
assert Permutation.rmul(a, b, c) == Permutation([1, 2, 3, 0])
assert Permutation.rmul(a, c) == Permutation([3, 2, 1, 0])
raises(TypeError, lambda: Permutation.rmul(b, c))
n = 6
m = 8
a = [Permutation.unrank_nonlex(n, i).array_form for i in range(m)]
h = list(range(n))
for i in range(m):
h = _af_rmul(h, a[i])
h2 = _af_rmuln(*a[:i + 1])
assert h == h2
def test_args():
p = Permutation([(0, 3, 1, 2), (4, 5)])
assert p._cyclic_form is None
assert Permutation(p) == p
assert p.cyclic_form == [[0, 3, 1, 2], [4, 5]]
assert p._array_form == [3, 2, 0, 1, 5, 4]
p = Permutation((0, 3, 1, 2))
assert p._cyclic_form is None
assert p._array_form == [0, 3, 1, 2]
assert Permutation([0]) == Permutation((0, ))
assert Permutation([[0], [1]]) == Permutation(((0, ), (1, ))) == \
Permutation(((0, ), [1]))
assert Permutation([[1, 2]]) == Permutation([0, 2, 1])
assert Permutation([[1], [4, 2]]) == Permutation([0, 1, 4, 3, 2])
assert Permutation([[1], [4, 2]], size=1) == Permutation([0, 1, 4, 3, 2])
assert Permutation(
[[1], [4, 2]], size=6) == Permutation([0, 1, 4, 3, 2, 5])
assert Permutation([[0, 1], [0, 2]]) == Permutation(0, 1, 2)
assert Permutation([], size=3) == Permutation([0, 1, 2])
assert Permutation(3).list(5) == [0, 1, 2, 3, 4]
assert Permutation(3).list(-1) == []
assert Permutation(5)(1, 2).list(-1) == [0, 2, 1]
assert Permutation(5)(1, 2).list() == [0, 2, 1, 3, 4, 5]
raises(ValueError, lambda: Permutation([1, 2], [0]))
# enclosing brackets needed
raises(ValueError, lambda: Permutation([[1, 2], 0]))
# enclosing brackets needed on 0
raises(ValueError, lambda: Permutation([1, 1, 0]))
raises(ValueError, lambda: Permutation([4, 5], size=10)) # where are 0-3?
# but this is ok because cycles imply that only those listed moved
assert Permutation(4, 5) == Permutation([0, 1, 2, 3, 5, 4])
def test_Cycle():
assert str(Cycle()) == '()'
assert Cycle(Cycle(1,2)) == Cycle(1, 2)
assert Cycle(1,2).copy() == Cycle(1,2)
assert list(Cycle(1, 3, 2)) == [0, 3, 1, 2]
assert Cycle(1, 2)(2, 3) == Cycle(1, 3, 2)
assert Cycle(1, 2)(2, 3)(4, 5) == Cycle(1, 3, 2)(4, 5)
assert Permutation(Cycle(1, 2)(2, 1, 0, 3)).cyclic_form, Cycle(0, 2, 1)
raises(ValueError, lambda: Cycle().list())
assert Cycle(1, 2).list() == [0, 2, 1]
assert Cycle(1, 2).list(4) == [0, 2, 1, 3]
assert Cycle(3).list(2) == [0, 1]
assert Cycle(3).list(6) == [0, 1, 2, 3, 4, 5]
assert Permutation(Cycle(1, 2), size=4) == \
Permutation([0, 2, 1, 3])
assert str(Cycle(1, 2)(4, 5)) == '(1 2)(4 5)'
assert str(Cycle(1, 2)) == '(1 2)'
assert Cycle(Permutation(list(range(3)))) == Cycle()
assert Cycle(1, 2).list() == [0, 2, 1]
assert Cycle(1, 2).list(4) == [0, 2, 1, 3]
assert Cycle().size == 0
raises(ValueError, lambda: Cycle((1, 2)))
raises(ValueError, lambda: Cycle(1, 2, 1))
raises(TypeError, lambda: Cycle(1, 2)*{})
raises(ValueError, lambda: Cycle(4)[a])
raises(ValueError, lambda: Cycle(2, -4, 3))
# check round-trip
p = Permutation([[1, 2], [4, 3]], size=5)
assert Permutation(Cycle(p)) == p
def test_from_sequence():
assert Permutation.from_sequence('SymPy') == Permutation(4)(0, 1, 3)
assert Permutation.from_sequence('SymPy', key=lambda x: x.lower()) == \
Permutation(4)(0, 2)(1, 3)
def test_resize():
p = Permutation(0, 1, 2)
assert p.resize(5) == Permutation(0, 1, 2, size=5)
assert p.resize(4) == Permutation(0, 1, 2, size=4)
assert p.resize(3) == p
raises(ValueError, lambda: p.resize(2))
p = Permutation(0, 1, 2)(3, 4)(5, 6)
assert p.resize(3) == Permutation(0, 1, 2)
raises(ValueError, lambda: p.resize(4))
def test_printing_cyclic():
p1 = Permutation([0, 2, 1])
assert repr(p1) == 'Permutation(1, 2)'
assert str(p1) == '(1 2)'
p2 = Permutation()
assert repr(p2) == 'Permutation()'
assert str(p2) == '()'
p3 = Permutation([1, 2, 0, 3])
assert repr(p3) == 'Permutation(3)(0, 1, 2)'
def test_printing_non_cyclic():
p1 = Permutation([0, 1, 2, 3, 4, 5])
assert srepr(p1, perm_cyclic=False) == 'Permutation([], size=6)'
assert sstr(p1, perm_cyclic=False) == 'Permutation([], size=6)'
p2 = Permutation([0, 1, 2])
assert srepr(p2, perm_cyclic=False) == 'Permutation([0, 1, 2])'
assert sstr(p2, perm_cyclic=False) == 'Permutation([0, 1, 2])'
p3 = Permutation([0, 2, 1])
assert srepr(p3, perm_cyclic=False) == 'Permutation([0, 2, 1])'
assert sstr(p3, perm_cyclic=False) == 'Permutation([0, 2, 1])'
p4 = Permutation([0, 1, 3, 2, 4, 5, 6, 7])
assert srepr(p4, perm_cyclic=False) == 'Permutation([0, 1, 3, 2], size=8)'
def test_deprecated_print_cyclic():
p = Permutation(0, 1, 2)
try:
Permutation.print_cyclic = True
with warns_deprecated_sympy():
assert sstr(p) == '(0 1 2)'
with warns_deprecated_sympy():
assert srepr(p) == 'Permutation(0, 1, 2)'
with warns_deprecated_sympy():
assert pretty(p) == '(0 1 2)'
with warns_deprecated_sympy():
assert latex(p) == r'\left( 0\; 1\; 2\right)'
Permutation.print_cyclic = False
with warns_deprecated_sympy():
assert sstr(p) == 'Permutation([1, 2, 0])'
with warns_deprecated_sympy():
assert srepr(p) == 'Permutation([1, 2, 0])'
with warns_deprecated_sympy():
assert pretty(p, use_unicode=False) == '/0 1 2\\\n\\1 2 0/'
with warns_deprecated_sympy():
assert latex(p) == \
r'\begin{pmatrix} 0 & 1 & 2 \\ 1 & 2 & 0 \end{pmatrix}'
finally:
Permutation.print_cyclic = None
def test_permutation_equality():
a = Permutation(0, 1, 2)
b = Permutation(0, 1, 2)
assert Eq(a, b) is S.true
c = Permutation(0, 2, 1)
assert Eq(a, c) is S.false
d = Permutation(0, 1, 2, size=4)
assert unchanged(Eq, a, d)
e = Permutation(0, 2, 1, size=4)
assert unchanged(Eq, a, e)
i = Permutation()
assert unchanged(Eq, i, 0)
assert unchanged(Eq, 0, i)
def test_issue_17661():
c1 = Cycle(1,2)
c2 = Cycle(1,2)
assert c1 == c2
assert repr(c1) == 'Cycle(1, 2)'
assert c1 == c2
def test_permutation_apply():
x = Symbol('x')
p = Permutation(0, 1, 2)
assert p.apply(0) == 1
assert isinstance(p.apply(0), Integer)
assert p.apply(x) == AppliedPermutation(p, x)
assert AppliedPermutation(p, x).subs(x, 0) == 1
x = Symbol('x', integer=False)
raises(NotImplementedError, lambda: p.apply(x))
x = Symbol('x', negative=True)
raises(NotImplementedError, lambda: p.apply(x))
def test_AppliedPermutation():
x = Symbol('x')
p = Permutation(0, 1, 2)
raises(ValueError, lambda: AppliedPermutation((0, 1, 2), x))
assert AppliedPermutation(p, 1, evaluate=True) == 2
assert AppliedPermutation(p, 1, evaluate=False).__class__ == \
AppliedPermutation