RE: how to extract parameter values
- To: mathgroup at smc.vnet.net
- Subject: [mg37324] RE: [mg37310] how to extract parameter values
- From: "DrBob" <drbob at bigfoot.com>
- Date: Wed, 23 Oct 2002 02:57:09 -0400 (EDT)
- Reply-to: <drbob at bigfoot.com>
- Sender: owner-wri-mathgroup at wolfram.com
Try this:
plot = ParametricPlot[{Cos[5t], Sin[3t]}, {
t, 0, 2ð}, AspectRatio -> Automatic];
lines = Cases[plot, _Line, Infinity]
To learn more about what's going on, look at
Head[plot]
plot[[1]]
plot[[2]]
Also note that you can operate on a graph my manipulating its first
argument. For instance, to do a coordinate transformation:
A = {{1, 2}, {-3, 1}};
Show[Graphics[plot[[1]] /. {x_, y_} -> A.{x, y}, plot[[2]]]]
Bobby
-----Original Message-----
From: Jan Mangaldan [mailto:jajem at yahoo.com]
To: mathgroup at smc.vnet.net
Subject: [mg37324] [mg37310] how to extract parameter values
I'd like to know how I can extract the parameter
values used by ParametricPlot in plotting a curve,
e.g. if ParametricPlot used points corresponding to
parameter values 2, 4, 6, etc... I need a way to get
the list {2, 4, 6, ...}.
One solution I know is this:
list={};
ParametricPlot[(AppendTo[list,t]; {f[t]
g[t]}),{t,tmin,tmax}];
The problem with this is that I get an error that
ParametricPlot cannot compile the function, and that
the plotting time is considerably slowed down.
especially if I have a high PlotPoints setting.
Any ideas?
Jan Mangaldan (~_~)
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