On Tue, 22 Sep 2009 18:47:50 -0700 (PDT) The_Fool <masterfu...@gmail.com> wrote:
> > I managed to create the symbolic polygamma function as psi(order,x). > Psi is limited in what it can do, though. I can get it to grab > special values from Maxima's or GiNaC's table, but I still cannot get > it to approximate any value of any integer order. It can be > differentiated, but not integrated. It seems that this is a > limitation of Maxima and GiNaC, not Sage. You're right, looking at the functions py_psi() and py_psi2() in sage/symbolic/pynac.pyx (I'm not giving line numbers since my file is heavily patched.), I see that they just raise NotImplementedError. You could have a go at implementing these functions using the psi function from mpmath: http://mpmath.googlecode.com/svn/tags/0.13/doc/build/functions/gamma.html#mpmath.functions.psi There is an example of how to call mpmath in the function py_li of sage/symbolic/pynac.pyx. If you post your code I can give some more pointers on how to use the pynac library better. For now, if you derived you class from sage.symbolic.function.PrimitiveFunction, I suggest not using the approx option, and using the __call__ = SFunction.__call__ line to bypass the __call__ method implemented in that class. This was done by the arctan2 function in sage/functions/trig.py which I gave as an example. I will not have internet access for a few days starting tomorrow. I'll try to catch up with e-mails once I'm back. Thanks. Cheers, Burcin --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
