SymTuple did not fulfill foo.func(*foo.args) == foo. This patch fixes that
by treating the constructor *args as items of the tuple, rather than expecting
exactly one tuple argument.
Added docstring, doctest and test + fixed some related whitespace errors.
---
sympy/physics/secondquant.py | 31 +++++++++++++++++--------------
sympy/physics/tests/test_secondquant.py | 9 +++++----
2 files changed, 22 insertions(+), 18 deletions(-)
diff --git a/sympy/physics/secondquant.py b/sympy/physics/secondquant.py
index 5d3f77b..269df9a 100644
--- a/sympy/physics/secondquant.py
+++ b/sympy/physics/secondquant.py
@@ -146,18 +146,27 @@ class TensorSymbol(Function):
class SymTuple(Basic):
+ """
+ Wrapper around the builtin tuple object
- def __new__(cls, arg_tuple, **kw_args):
- """
- the wrapped tuple is available as self.args
- """
- obj = Basic.__new__(cls,*arg_tuple, **kw_args)
- return obj
+ The SymTuple is a subclass of Basic, so that it works well in the
+ Sympy framework. The wrapped tuple is available as self.args, but
+ you can also access elements or slices with [:] syntax.
+
+ >>> from sympy import symbols
+ >>> from sympy.physics.secondquant import SymTuple
+ >>> a, b, c, d = symbols('a b c d')
+ >>> SymTuple(a, b, c)[1:]
+ SymTuple(b, c)
+ >>> SymTuple(a, b, c).subs(a, d)
+ SymTuple(d, b, c)
+
+ """
def __getitem__(self,i):
if isinstance(i,slice):
indices = i.indices(len(self))
- return SymTuple(tuple([self.args[i] for i in range(*indices)]))
+ return SymTuple(*[self.args[i] for i in range(*indices)])
return self.args[i]
def __len__(self):
@@ -166,12 +175,6 @@ def __len__(self):
def __contains__(self,item):
return item in self.args
- def _eval_subs(self,old,new):
- if self==old:
- return new
- t=tuple([ el._eval_subs(old,new) for el in self.args])
- return self.__class__(t)
-
def _tuple_wrapper(method):
"""
@@ -181,7 +184,7 @@ def wrap_tuples(*args, **kw_args):
newargs=[]
for arg in args:
if type(arg) is tuple:
- newargs.append(SymTuple(arg))
+ newargs.append(SymTuple(*arg))
else:
newargs.append(arg)
return method(*newargs, **kw_args)
diff --git a/sympy/physics/tests/test_secondquant.py
b/sympy/physics/tests/test_secondquant.py
index f286098..61b2276 100644
--- a/sympy/physics/tests/test_secondquant.py
+++ b/sympy/physics/tests/test_secondquant.py
@@ -15,16 +15,17 @@
def test_SymTuple():
- t = (1,2,3,4)
- st = SymTuple(t)
+ t = (1, 2, 3, 4)
+ st = SymTuple(*t)
assert set(t) == set(st)
assert len(t) == len(st)
assert set(t[:2]) == set(st[:2])
assert isinstance(st[:], SymTuple)
- assert st == SymTuple((1,2,3,4))
+ assert st == SymTuple(1, 2, 3, 4)
+ assert st.func(*st.args) == st
p,q,r,s = symbols('pqrs')
t2=(p,q,r,s)
- st2 = SymTuple(t2)
+ st2 = SymTuple(*t2)
assert st2.atoms() == set(t2)
def test_PermutationOperator():
--
1.6.5
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