Rajeev, Hi, great question. Just to understand the context. What are x and y? Are they a creation/annihilation operator pair? As you may know, we have quite a bit of code in sympy.physics.quantum for handling various things from quantum mechanics in a symbolic manner, include commutation relationships. One thing that we have is a commutator/anticommutator aware bubble sort algorithm that could probably be adapted to do what you want.
But, before we dive into that can you say a bit more about what exactly you are trying to do? Thanks, Brian On Mon, May 23, 2011 at 9:55 PM, Rajeev Singh <[email protected]> wrote: > Hi, > I asked this question on sage mailing list already and it seems appropriate > to ask here as well. I wish to simplify some calculation that appear in > quantum mechanics. To begin we use non-commutative variables as - > sage: x, y = sympy.symbols('xy', commutative=False) > sage: sympy.expand((x+y)**3) > x**2*y + y**2*x + x*y**2 + y*x**2 + x**3 + y**3 + x*y*x + y*x*y > I want to impose the commutation relation [x,y]=1 and bring the expression > to normal form (i.e. in all terms y appears before x, e.g. x*y gets replaced > by y*x + 1). Is it possible to do this? > If not then can I get the expression such that x*y**2 appears as x*y*y? > Thanks in advance. > Regards, > Rajeev > > -- > 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. > -- Brian E. Granger Cal Poly State University, San Luis Obispo [email protected] and [email protected] -- 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.
