Re: ImplicitPlot problem
- To: mathgroup at smc.vnet.net
- Subject: [mg68169] Re: ImplicitPlot problem
- From: "David W. Cantrell" <DWCantrell at sigmaxi.net>
- Date: Thu, 27 Jul 2006 05:29:48 -0400 (EDT)
- References: <ea72a7$k44$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Antonios Papazoglou <antonios.papazoglou at epfl.ch> wrote:
> Hello,
>
> I'm using ImplicitPlot to plot the line of zeros of a complicated
> function f(x,y) on the (x,y) plane.
I hope that complicated function is continuous; otherwise, no method
related to yours will find the zeros well.
> However, not only the line of zeros
> is ploted, but also the line where the function f diverges.
>
> Simple example: take f(x,y)=x/y
> Then ImplicitPlot plots a cross, although the zeros are only the line
> x=0.
You're right.
> This is probably due to a problem of the underlying ContourPlot function
> that is used implicitly.
>
> Is there a way around this problem?
Try this example using DensityPlot:
DensityPlot[Abs[x/y], {x, -3, 3}, {y, -3, 3}, Mesh -> False,
PlotPoints -> 600, PlotRange -> {0, .01}]
Note that I took Abs of the function and specified a small positive value
for the upper limit of PlotRange. The smaller that value is, the more
PlotPoints will be needed.
Perhaps someone else will have a better suggestion.
David