Re: ParametricPlot - a feature or a bug?
- To: mathgroup at smc.vnet.net
- Subject: [mg39462] Re: ParametricPlot - a feature or a bug?
- From: peter weijnitz <pewei at algonet.se>
- Date: Mon, 17 Feb 2003 04:34:07 -0500 (EST)
- References: <b2nrh3$6oq$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
It seems to have something to do with the way plotting is done, if you have a large
interval (e.g 0-500Pi) Mathematica still use just the default number of plot points,
(50 I think) and straight lines are drawn between the points. So you get the
annulus.
If you increase the number of plotpoints the problem goes away. see below
ParametricPlot[{Cos[t], Sin[t]}, {t, 0, 500 Pi}, AspectRatio -> Automatic,
PlotPoints -> 1000];
Peter W
Vladimir Bondarenko wrote:
> Hello,
>
> 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? ;-)
>
> Best wishes,
>
> Vladimir Bondarenko
> Mathematical and Production Director
> Symbolic Testing Group
>
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