On 22 June 2012 22:13, Guru Devanla <[email protected]> wrote: > Hello All, > > Can someone explain why 2 objects in the following statements give me the > same id() value? > > >>>> A, B = symbols('A B', commutative=False) >>>> x = A*B >>>> print id(x) > 169853492 >>>> y = A*B >>>> print id(y) > 169853492
Because these are the same object A*B. x and y are just labels pointing to an instance. > > I run into this problem while trying to implement some operation on Trace > module. > > Say, I have Tr(A*B*C) . Now, the user wants to create another instance of > Tr(C*A*B). But, both objects are getting the same id, meaning I am not > able to create 2 different objects one which prints at Tr(A*B*C) and another > which prints as Tr(C*A*B). Note, that I have not yet overridden > _hashable_contents to compare the args ( using the cyclic property of > trace). > Stupid question: Did you correctly set commutable=False for A,B and C. Does Tr somehow override them? > Am I missing something basic? Or is there a way to override this > behavior, if necessary > > Thanks > Guru > > > > > > > > > > > > > > > > > > > > > -- > You received this message because you are subscribed to the Google Groups > "sympy" group. > To view this discussion on the web visit > https://groups.google.com/d/msg/sympy/-/lFlq7OJjqlkJ. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/sympy?hl=en. -- You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/sympy?hl=en.
