On Fri, 18 Sep 2009 15:47:45 -0700 (PDT) The_Fool <masterfu...@yahoo.com> wrote:
> While working with the derivative of the Gamma function, the digamma > function is obviously involved. The sage "diff" function does show Γ > '(x) == Γ(x)ψ(x) like it should, however, the digamma function (called > psi in sage) is not defined whenever I try to do anything with it. It > seems as if only the output of "diff" can use this function. This is because GiNaC (the library Sage uses for symbolic expressions) knows about the digamma function, but Sage doesn't. > Is there any way to permanently keep this function defined so I can > plot with it, conduct symbolic and numeric calculations with it, and > so on like any other function? Defining a function psi, similar to the way arctan2 is defined in line 422 of sage/functions/trig.py should fix this. I opened a ticket: http://trac.sagemath.org/sage_trac/ticket/6961 Thanks. 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 -~----------~----~----~----~------~----~------~--~---
