Re: ContourPlot problem

*To*: mathgroup at smc.vnet.net*Subject*: [mg90085] Re: ContourPlot problem*From*: Helen Read <read at math.uvm.edu>*Date*: Sat, 28 Jun 2008 05:53:11 -0400 (EDT)*References*: <g42ere$no5$1@smc.vnet.net>

Jorge Cortes wrote: > Hello, > > I've noticed the following problem with ContourPlot (I'm using > Mathematica 6..0.3) and a simple exponential function. > > If you try the domain {x,-3,3}, {y,-3,3} > > ContourPlot[Exp[-x^2 - 2 y^2], {x, -3,3}, {y, -3, 3}, > Contours -> {.1,.2, .3, .4, .5, .6, .7, .8, .9, 1}, > ContourLabels -> True, ContourShading -> False] > > you only get one contour (the one corresponding to .1). However, if > you shrink the domain to {x,-2,2}, {y,-2,2}, surprisingly you get all > the contours (?) > > ContourPlot[Exp[-x^2 - 2 y^2], {x, -2,2}, {y, -2, 2}, > Contours -> {.1,.2, .3, .4, .5, .6, .7, .8, .9, 1}, > ContourLabels -> True, ContourShading -> False] > > Does anybody has an explanation for this? Thanks! I have found ContourPlot to be a little squirrelly in its choice of PlotRange. Your example does work if you set the PlotRange explicitly. ContourPlot[Exp[-x^2 - 2 y^2], {x, -3, 3}, {y, -3, 3}, Contours -> {.1, .2, .3, .4, .5, .6, .7, .8, .9, 1}, ContourLabels -> True, ContourShading -> False, PlotRange -> 3] -- Helen Read University of Vermont