Actually, Sage's 2d plotting has a similar problem, though for
different reasons; see http://trac.sagemath.org/sage_trac/ticket/3985
. I believe that in both cases, though, there could be improvement of
"automatic" detecting of the "right" values.
That said, you may want to try something using the command show(), at
least for your second question. E.g.
sage: P=plot3d(lambda x,y : (bessel_Y(y,x,"scipy",53)).real(),
(-0.002,0.002), (-1,1))
sage: P.show(aspect_ratio=[200,1,1/2000])
yields something approximately like the original graph, though of
course it still includes all values. For more info, you can look at
sage: P.show?
Unfortunately, something like xmax, xmin in the 2d show command seems
to be missing in 3d plotting; at least, using them is ignored by
Jmol. So if that is the main thing you are asking for, it is not yet
implemented.
- kcrisman
On Jun 2, 6:16 am, littlemathteacher <relational...@gmail.com> wrote:
> Sorry, me again.
> Maybe I was wrong to say Sage scales "up". Maybe Sage scales "down".
> Howto aviod this?
>
> Thanks
>
> On 2 Jun., 08:44, littlemathteacher <relational...@gmail.com> wrote:
>
> > Dear supporters,
>
> > again thanks for the great support.
>
> > One thing I am missing (or simply not understanding) is 3dplotting
> > without automatically scaled up range of the function value.
>
> > (This is just my first example at hand and surely not a good one:
> > y, x = var ('x,y')
> > plot3d(lambda x,y : (bessel_Y(y,x,"scipy",53)).real(), (-0.002,0.002),
> > (-1,1))
>
> > #Put some broader x-range in to see what I mean.)
>
> > Please excuse this sloppy written description: Jmol and Sage seem to
> > try to plot the whole graph even at singularities, then "give up" (at
> > a level I don't know how to fix) but leave the picture with the scaled
> > up value range.
>
> > Use this link to see what I mean would be useful sometimes (and please
> > do not blame me because my plot above is another thing as seen there -
> > I am just playing around and I just took the first example at hand):
>
> >http://mathworld.wolfram.com/ModifiedBesselFunctionoftheSecondKind.html
>
> > There the value range is simply cut at some point. In the german
> > wikipedia article on the exponential function it is done in a similar
> > way by Maple and the whole picture is scaled equally in all
> > dimensions:
>
> >http://de.wikipedia.org/w/index.php?title=Datei:Exp_re.png&filetimest...
>
> > (Put the two lines together without intermedate space.)
>
> > Is there a way to limit the value range in a 3dplot other than
> > limiting the input range (I want to see, say, the region around the
> > singularity)?
>
> > Yours, littlemathteacher
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