def __new__(cls, *args, **options):
components = {}
# Check each arg and simultaneously learn the components
for i, arg in enumerate(args):
if not isinstance(arg, cls._expr_type):
if isinstance(arg, Mul):
arg = cls._mul_func(*(arg.args))
elif isinstance(arg, Add):
arg = cls._add_func(*(arg.args))
else:
raise TypeError(
str(arg) + " cannot be interpreted correctly")
# If argument is zero, ignore
if arg == cls.zero:
continue
# Else, update components accordingly
if hasattr(arg, "components"):
for x in arg.components:
components[x] = components.get(x, 0) + arg.components[x]
temp = list(components.keys())
for x in temp:
if components[x] == 0:
del components[x]
# Handle case of zero vector
if len(components) == 0:
return cls.zero
# Build object
newargs = [x * components[x] for x in components]
obj = super().__new__(cls, *newargs, **options)
if isinstance(obj, Mul):
return cls._mul_func(*obj.args)
assumptions = {'commutative': True}
obj._assumptions = StdFactKB(assumptions)
obj._components = components
obj._sys = (list(components.keys()))[0]._sys
return obj
def __new_stage2__(cls, name, **assumptions):
if not isinstance(name, string_types):
raise TypeError("name should be a string, not %s" % repr(type(name)))
obj = Expr.__new__(cls)
obj.name = name
# TODO: Issue #8873: Forcing the commutative assumption here means
# later code such as ``srepr()`` cannot tell whether the user
# specified ``commutative=True`` or omitted it. To workaround this,
# we keep a copy of the assumptions dict, then create the StdFactKB,
# and finally overwrite its ``._generator`` with the dict copy. This
# is a bit of a hack because we assume StdFactKB merely copies the
# given dict as ``._generator``, but future modification might, e.g.,
# compute a minimal equivalent assumption set.
tmp_asm_copy = assumptions.copy()
# be strict about commutativity
is_commutative = fuzzy_bool(assumptions.get('commutative', True))
assumptions['commutative'] = is_commutative
obj._assumptions = StdFactKB(assumptions)
obj._assumptions._generator = tmp_asm_copy # Issue #8873
return obj
def __new_stage2__(cls, name, **assumptions):
assert isinstance(name, str), repr(type(name))
obj = Expr.__new__(cls)
obj.name = name
obj._assumptions = StdFactKB(assumptions)
return obj
