Re: contour with latest CVS and gnuplot 4.0

[John W. Eaton]

On 23-Mar-2007, David Bateman wrote:

| John W. Eaton wrote:
| > On 23-Mar-2007, David Bateman wrote:
| >
| > | I get no output with
| > | 
| > | [x,y] = meshgrid(-10:10); z =1./sqrt(x.^2 + y.^2); contour(z)
| > | 
| > | or with
| > | 
| > | [x,y] = meshgrid(-10:10); z =1./sqrt(x.^2 + y.^2); contour(x,y,z)
| > | 
| > | with a recent CVS and gnuplot 4.0. Is this expected? If it is expected
| > | is there a way around it?
| >
| > The contour function was changed recently to use the contour functions
| > from octplot to generate the contour lines which are then plotted
| > using 2-d plotting commands (the line function).  The first thing that
| > happens in a call like
| >
| >   contour (z)
| >
| > is
| >
| >   [c, lev] = contourc (z);
| >
| > For your Z, I see
| >
| >   c = [](2x0)
| >   lev =
| >
| >      Inf   Inf   Inf   Inf   Inf   Inf   Inf   Inf   Inf   Inf
| >
| > and there is nothing to plot.  I haven't looked to see why this might
| > be happening.
| >
| > jwe
| >
| >   
| Ok it seems that contourc doesn't handle "Inf"'s.. This
| 
|  [x,y] = meshgrid(-10:10); z =1./sqrt(x.^2 + y.^2); z(11,11) = 2;
| contour(x,y,z)
| 
| works..

OK, maybe someone can dig into contourc and improve it?

jwe