Mike Witt wrote: > On 08/21/2008 06:55:48 PM, Joel B. Mohler wrote: >> On Thursday 21 August 2008 01:58:23 pm Mike Witt wrote: >>> I'm looking for a work-around for the situation where I would normally >>> call parametric_plot (or plot, for that matter) with a function, and in >>> some particular case that function turns out to evaluate to a constant. >>> >>> For example: >>> >>> sage: def f(a,b): return e^(a+b*I) >>> ....: >>> sage: parametric_plot([real(f(x,1)),imag(f(x,1))], -pi, pi) >>> >>> Works as expected >>> >>> sage: parametric_plot([real(f(x,-1)),imag(f(x,-1))], -pi, pi) >>> >>> Works as expected >>> >>> sage: parametric_plot([real(f(x,0)),imag(f(x,0))], -pi, pi) >>> >>> Gives a page full of errors, which I interpret to mean that there >>> was a problem plotting because imag(f(x,0)) evaluates to a constant. >>> >>> I believe that this is the same issue described in: >>> >>> http://trac.sagemath.org/sage_trac/ticket/2410 >> I'm the person that entered the trac ticket and the point of that trac >> ticket >> is precisely the (mis-)functionality you are describing. I'm truly >> mystified by the other responses in this thread. To me, this is an obvious >> bug... >> >> -- >> Joel > > Thanks Joel. I was beginning to wonder if I was nuts. Just to summarize what > I've found out so far. The work-arounds suggested by David Joyner, Mike > Hansen, > and Carl Witty all work under certain assumptions, but none of the three > provides a completely general fix as far as I can see. Using a combination of > the techniques I am able to do what I want. But I am for whatever it's worth > I'd certainly like to add my vote that tickets #2409 and #2410 should get > attention. This issue with parametric_plot is certainly *very* confusing > to a newcomer.
Here's yet another method: sage: from sage.ext.fast_eval import fast_float sage: plot(fast_float(1), -1, 2) sage: parametric_plot((fast_float(1),t),-12,12) Now, why in the world the plot functions aren't calling fast_float, I don't know. I thought that's what they did. I'm looking into it for a few minutes, at least. Jason --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
