William Stein wrote: > 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
Since you were busy, I have created these trac tickets on your behalf (6423 and 6424). However, I feel you should look over them, set appropriate milestones, categories, priority etc, as I do not know enough about this. Dave --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
