Re: PlotVectorField Package (easy question?)
- To: mathgroup at smc.vnet.net
- Subject: [mg15901] Re: PlotVectorField Package (easy question?)
- From: Martin Kraus <mkraus at theorie3.physik.uni-erlangen.de>
- Date: Wed, 17 Feb 1999 23:33:44 -0500
- Organization: Regionales Rechenzentrum Erlangen, Germany
- References: <7a29n1$1pi@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Adam Price wrote:
>
> I am running Mathematica 3.0 on a G3, and having trouble using
> <<Graphics`PlotVectorField`
>
> ******************************
> In[55]:=
>
> <<Graphics`PlotField`
>
> In[56]:=
> (PlotGradientField[{2 x^2 + y, 3 x - y}, {x,-10,10 }, {y,-10,10}]
>
> Out[56]=
>
> "Graphics`PlotField`PlotVectorField[
> {{4 x, 3}, {1, -1} , {x, -10, 10}, {y, -10, 10},
> {A long list of all the options}]
>
>
> ******************
> ??PlotGradientField gives the help information from the package, but it
> still won't plot. ??PlotVectorField returns: Global['PlotVectorField']
>
> I have tried clearing everything, running from inside PlotField.m, and
> even evaluating the example pages from the help manual.
> PlotVectorField just won't run. What am I doing wrong?
>
> -Adam
PlotGradientField plots the gradient of a scalar function, thus,
the first argument is supposed to be an arithmetic expression
for a scalar (e.g. x^2+y^2) but not a list.
In order to plot the vector field {2 x^2+y,3 x-y} you should use
PlotVectorField:
PlotVectorField[{2 x^2 + y, 3 x - y}, {x,-10,10 }, {y,-10,10}]
Hope that helps
Martin Kraus