Re: ParametricPlot - a feature or a bug?
- To: mathgroup at smc.vnet.net
- Subject: [mg39461] Re: [mg39447] ParametricPlot - a feature or a bug?
- From: BobHanlon at aol.com
- Date: Mon, 17 Feb 2003 04:34:03 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
In a message dated 2/16/03 7:14:36 AM, vvb at mail.strace.net writes:
> While trying to plot complex parametric plots with large values
> of the parameter I run into a problem which boils down to the
> following simple observation.
>
> a) ParametricPlot[{Cos[t], Sin[t]}, {t, 0, 1 Pi}, AspectRatio ->
> Automatic];
>
> A perfect circumference.
>
> b) ParametricPlot[{Cos[t], Sin[t]}, {t, 0, 200 Pi}, AspectRatio ->
> Automatic];
>
> Instead of a circumference, not a very wide annulus.
>
> c) ParametricPlot[{Cos[t], Sin[t]}, {t, 0, 500 Pi}, AspectRatio ->
> Automatic];
>
> An annulus which width is equal to the radius of the inner
> circumference.
>
> d) ParametricPlot[{Cos[t], Sin[t]}, {t, 0, 1000 Pi}, AspectRatio ->
> Automatic];
>
> A black ring with tiny white spots.
>
> e) ParametricPlot[{Cos[t], Sin[t]}, {t, 0, 10^19 Pi}, AspectRatio ->
> Automatic];
>
> A funny net.
>
> f) ParametricPlot[{Cos[t], Sin[t]}, {t, 0, 10^20 Pi}, AspectRatio ->
> Automatic];
>
> A segment.
>
> g) ParametricPlot[{Cos[t], Sin[t]}, {t, 0, 10^26 Pi}, AspectRatio ->
> Automatic];
>
> Only the axes are shown. There is no graph itself.
>
>
> Is (at least a part of the shown output) a feature or a bug?
>
> (By the way, before answering why do not try to solve the same
> problems with a couple of other systems? ;-)
>
>
It is the natural consequence of undersampling. Increase the PlotPoints.
n = 2000;
ParametricPlot[{Cos[t], Sin[t]}, {t, 0, n* Pi},
AspectRatio -> Automatic, PlotPoints -> 10*n];
Bob Hanlon