On Wed, Jun 24, 2009 at 4:18 AM, Dr. David Kirkby<david.kir...@onetel.net> wrote: > > Mike Hansen wrote: >> On Tue, Jun 23, 2009 at 6:23 PM, Dr. David >> Kirkby<david.kir...@onetel.net> wrote: >>> exp(-x^i).integral(x,0,1) returns >>> >>> Traceback (click to the left for traceback) >>> ... >>> Is %i an integer? >>> >>> Ouch! Any Sage comments?
Thanks for testing this. It is good to know about, and I would think it is definitely a bug in Maxima. >> >> This is just coming from Maxima: >> >> (%i3) integrate(exp(-x^(%i)),x,0,1); >> Is %i an integer? >> >> --Mike > > So it does appear a bit inconsistent, where i is reconised as sqrt(-1) > at one time, and not at another. A large amount of the symbolic functionality that uses Maxima has issues like this, but unfortunately there is basically nothing we can do about it, except continue with projects to rewrite the parts of Sage that call Maxima so that they don't call Maxima. So this class of bugs should be very good motivation to continue to work on implementing symbolic integration ourselves (and/or further improving sympy!). By the way, evidently one can no longer convert I=sqrt(-1) to sympy: sage: (x+sqrt(2))._sympy_() x + 2**(1/2) sage: (x+I)._sympy_() SympifyError: SympifyError: I is NOT a valid SymPy expression Anyway, I see two trac tickets to report above, and I hope somebody reports them, since I have to write a talk right now. -- William --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to sage-devel-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
