def __new__(cls, partition):
"""
Generates a new partition object.
This method also verifies if the arguments passed are
valid and raises a ValueError if they are not.
Examples
========
>>> from sympy.combinatorics.partitions import Partition
>>> a = Partition([[1, 2], [3]])
>>> a
{{1, 2}, {3}}
>>> a.partition
[[1, 2], [3]]
>>> len(a)
2
>>> a.members
(1, 2, 3)
"""
args = partition
if not all(isinstance(part, list) for part in args):
raise ValueError("Partition should be a list of lists.")
# sort so we have a canonical reference for RGS
partition = sorted(sum(partition, []), key=default_sort_key)
if has_dups(partition):
raise ValueError("Partition contained duplicated elements.")
obj = C.FiniteSet.__new__(cls, list(map(C.FiniteSet, args)))
obj.members = tuple(partition)
obj.size = len(partition)
return obj
def __new__(cls, partition):
"""
Generates a new partition object.
This method also verifies if the arguments passed are
valid and raises a ValueError if they are not.
Examples
========
>>> from sympy.combinatorics.partitions import Partition
>>> a = Partition([[1, 2], [3]])
>>> a
{{1, 2}, {3}}
>>> a.partition
[[1, 2], [3]]
>>> len(a)
2
>>> a.members
(1, 2, 3)
"""
args = partition
if not all(isinstance(part, list) for part in args):
raise ValueError("Partition should be a list of lists.")
# sort so we have a canonical reference for RGS
partition = sorted(sum(partition, []), key=default_sort_key)
if has_dups(partition):
raise ValueError("Partition contained duplicated elements.")
obj = C.FiniteSet.__new__(cls, map(C.FiniteSet, args))
obj.members = tuple(partition)
obj.size = len(partition)
return obj
def preprocess(cls, gens):
if isinstance(gens, Basic):
gens = (gens, )
elif len(gens) == 1 and hasattr(gens[0], '__iter__'):
gens = gens[0]
if gens == (None, ):
gens = ()
elif has_dups(gens):
raise GeneratorsError("duplicated generators: %s" % str(gens))
elif any(gen.is_commutative is False for gen in gens):
raise GeneratorsError("non-commutative generators: %s" % str(gens))
return tuple(gens)
def preprocess(cls, gens):
if isinstance(gens, Basic):
gens = (gens,)
elif len(gens) == 1 and hasattr(gens[0], '__iter__'):
gens = gens[0]
if gens == (None,):
gens = ()
elif has_dups(gens):
raise GeneratorsError("duplicated generators: %s" % str(gens))
elif any(gen.is_commutative is False for gen in gens):
raise GeneratorsError("non-commutative generators: %s" % str(gens))
return tuple(gens)
def preprocess(cls, gens):
from sympy import Wild, Symbol
from sympy.tensor.indexed import Slice, Indexed
from sympy.functions.elementary.exponential import ExpBase
if isinstance(gens, Basic):
gens = (gens, )
elif len(gens) == 1 and hasattr(
gens[0], '__iter__') and not isinstance(
gens[0], (Wild, Slice, Indexed, Symbol, ExpBase)):
gens = gens[0]
if gens == (None, ):
gens = ()
elif has_dups(gens):
raise GeneratorsError("duplicated generators: %s" % str(gens))
# elif any(gen.is_commutative == False for gen in gens):
# raise GeneratorsError("non-commutative generators: %s" % str(gens))
return tuple(gens)
def test_has_dups():
assert has_dups(set()) is False
assert has_dups(list(range(3))) is False
assert has_dups([1, 2, 1]) is True
def eval(cls, *args):
if all(isinstance(a, (int, Integer)) for a in args):
return eval_levicivita(*args)
if has_dups(args):
return S.Zero
def pde_separate(eq, fun, sep, strategy='mul'):
"""Separate variables in partial differential equation either by additive
or multiplicative separation approach. It tries to rewrite an equation so
that one of the specified variables occurs on a different side of the
equation than the others.
:param eq: Partial differential equation
:param fun: Original function F(x, y, z)
:param sep: List of separated functions [X(x), u(y, z)]
:param strategy: Separation strategy. You can choose between additive
separation ('add') and multiplicative separation ('mul') which is
default.
Examples
========
>>> from sympy import E, Eq, Function, pde_separate, Derivative as D
>>> from sympy.abc import x, t
>>> u, X, T = map(Function, 'uXT')
>>> eq = Eq(D(u(x, t), x), E**(u(x, t))*D(u(x, t), t))
>>> pde_separate(eq, u(x, t), [X(x), T(t)], strategy='add')
[exp(-X(x))*Derivative(X(x), x), exp(T(t))*Derivative(T(t), t)]
>>> eq = Eq(D(u(x, t), x, 2), D(u(x, t), t, 2))
>>> pde_separate(eq, u(x, t), [X(x), T(t)], strategy='mul')
[Derivative(X(x), x, x)/X(x), Derivative(T(t), t, t)/T(t)]
See Also
========
pde_separate_add, pde_separate_mul
"""
do_add = False
if strategy == 'add':
do_add = True
elif strategy == 'mul':
do_add = False
else:
assert ValueError('Unknown strategy: %s' % strategy)
if isinstance(eq, Equality):
if eq.rhs != 0:
return pde_separate(Eq(eq.lhs - eq.rhs), fun, sep, strategy)
assert eq.rhs == 0
# Handle arguments
orig_args = list(fun.args)
subs_args = []
for s in sep:
for j in range(0, len(s.args)):
subs_args.append(s.args[j])
if do_add:
functions = reduce(operator.add, sep)
else:
functions = reduce(operator.mul, sep)
# Check whether variables match
if len(subs_args) != len(orig_args):
raise ValueError("Variable counts do not match")
# Check for duplicate arguments like [X(x), u(x, y)]
if has_dups(subs_args):
raise ValueError("Duplicate substitution arguments detected")
# Check whether the variables match
if set(orig_args) != set(subs_args):
raise ValueError("Arguments do not match")
# Substitute original function with separated...
result = eq.lhs.subs(fun, functions).doit()
# Divide by terms when doing multiplicative separation
if not do_add:
eq = 0
for i in result.args:
eq += i/functions
result = eq
svar = subs_args[0]
dvar = subs_args[1:]
return _separate(result, svar, dvar)
def eval(cls, *args):
if all(isinstance(a, (int, Integer)) for a in args):
return eval_levicivita(*args)
if has_dups(args):
return S.Zero
def test_has_dups():
assert has_dups(set()) is False
assert has_dups(range(3)) is False
assert has_dups([1, 2, 1]) is True
def __new__(cls, sym, condition, base_set=S.UniversalSet):
from sympy.core.function import BadSignatureError
from sympy.utilities.iterables import flatten, has_dups
sym = _sympify(sym)
flat = flatten([sym])
if has_dups(flat):
raise BadSignatureError("Duplicate symbols detected")
base_set = _sympify(base_set)
if not isinstance(base_set, Set):
raise TypeError('base set should be a Set object, not %s' %
base_set)
condition = _sympify(condition)
if isinstance(condition, FiniteSet):
condition_orig = condition
temp = (Eq(lhs, 0) for lhs in condition)
condition = And(*temp)
SymPyDeprecationWarning(
feature="Using {} for condition".format(condition_orig),
issue=17651,
deprecated_since_version='1.5',
useinstead="{} for condition".format(condition)).warn()
condition = as_Boolean(condition)
if condition is S.true:
return base_set
if condition is S.false:
return S.EmptySet
if isinstance(base_set, EmptySet):
return base_set
# no simple answers, so now check syms
for i in flat:
if not getattr(i, '_diff_wrt', False):
raise ValueError('`%s` is not symbol-like' % i)
if base_set.contains(sym) is S.false:
raise TypeError('sym `%s` is not in base_set `%s`' %
(sym, base_set))
know = None
if isinstance(base_set, FiniteSet):
sifted = sift(base_set,
lambda _: fuzzy_bool(condition.subs(sym, _)))
if sifted[None]:
know = FiniteSet(*sifted[True])
base_set = FiniteSet(*sifted[None])
else:
return FiniteSet(*sifted[True])
if isinstance(base_set, cls):
s, c, b = base_set.args
def sig(s):
return cls(s, Eq(adummy, 0)).as_dummy().sym
sa, sb = map(sig, (sym, s))
if sa != sb:
raise BadSignatureError('sym does not match sym of base set')
reps = dict(zip(flatten([sym]), flatten([s])))
if s == sym:
condition = And(condition, c)
base_set = b
elif not c.free_symbols & sym.free_symbols:
reps = {v: k for k, v in reps.items()}
condition = And(condition, c.xreplace(reps))
base_set = b
elif not condition.free_symbols & s.free_symbols:
sym = sym.xreplace(reps)
condition = And(condition.xreplace(reps), c)
base_set = b
# flatten ConditionSet(Contains(ConditionSet())) expressions
if isinstance(condition, Contains) and (sym == condition.args[0]):
if isinstance(condition.args[1], Set):
return condition.args[1].intersect(base_set)
rv = Basic.__new__(cls, sym, condition, base_set)
return rv if know is None else Union(know, rv)
