This looks like a bug in SymPy. Can you paste the full traceback? Aaron Meurer
On Sat, Jul 11, 2015 at 11:05 AM, 万博 <[email protected]> wrote: > Greetings, everyone. > I am trying to use sympy calculate a perturbation problem, which > looks like: > > <https://lh3.googleusercontent.com/-85X7sj42udw/VaE8SsgPpTI/AAAAAAAAAFs/4aHMDhFRZOY/s1600/per.png> > In sympy, I think it's safe to use code like:(all elements are > Matrices.) > > i=Symbol("i",integer=True) > summation( (u.H*Hamil*p.col(i))*(p.col(i).H*Hamil*u) , (i,0,5)) > > However, it gives the error: > IndexError: Invalid index a[i] > > I have calculated manually the sum, which gives the right result. SO, > I guess there is some misunderstanding about summation(). > Any advises about solving this would be appreciated. > Thanks. > > -- > You received this message because you are subscribed to the Google Groups > "sympy" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/sympy. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sympy/6dee658f-88ac-4ed9-9061-ab7859cf9f9e%40googlegroups.com > <https://groups.google.com/d/msgid/sympy/6dee658f-88ac-4ed9-9061-ab7859cf9f9e%40googlegroups.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAKgW%3D6K720KV-ek4pyxmZtw1HkuRjqvFwR1HThVRUWWn1h8AGg%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
