Re: Re: Problem with RegionFunction
- To: mathgroup at smc.vnet.net
- Subject: [mg88126] Re: [mg88084] Re: Problem with RegionFunction
- From: "W_Craig Carter" <ccarter at mit.edu>
- Date: Fri, 25 Apr 2008 05:30:30 -0400 (EDT)
- References: <fukern$s4l$1@smc.vnet.net> <fumqti$sc8$1@smc.vnet.net>
Hello Zac,
This was explained to me the following way. WIthin Manipulate, the
PerformanceGoal option switches from
Speed to Quality when a manipulate variable stops changing. Thus, the
change in appearance of Graphics3D objects while sliding. To handle
the boundaries of a plot well, values are probed on either side of the
boundary even though they are not going to appear on the final plot.
PerformanceGoal as I understand it, changes the way that plot resolves
the boundaries and thus your 0^0.
I hope this explanation is not too far off the mark.
WCC
On Thu, Apr 24, 2008 at 5:56 AM, zac <replicatorzed at gmail.com> wrote:
> Thank you for the answers.
>
> I understand that the case where x=0 and y=0 is undefined, but I don't
> understand why does Mathematica compute this case when ranges are
> given explicitely to avoid such situations? Why do I have to define
> the regionfunction to exclude x=0 and y=0 (as Fred suggested it)? Is
> it not trivial to exclude these as the PlotRange dictates it? Why is
> it that the problem does not surface when I omit the Manipulate[...]
> wrap?
> Istvan
>
>
>
> On Apr 23, 10:10 am, Jens-Peer Kuska <ku... at informatik.uni-leipzig.de>
> wrote:
> > Hi,
> >
> > try
> >
> > Manipulate[
> > Plot3D[Sin[x]*Cos[y], {x, 1, 10}, {y, 2, 10},
> > RegionFunction -> Function[{x, y}, 45 <= (y^x)],
> > Exclusions -> x == 0], {dummy, {True, False}}]
> >
> > because y^x for x==0 and y==0 is undefined.
> >
> > Regards
> > Jens
>
>
--
W. Craig Carter