Re: Plotting a function of 3 variables ?

[Mike Miller]

On Wed, Apr 25, 2012 at 1:00 PM, Martin Helm <address@hidden> wrote:
> Oisin found meanwhile that scatter3 does what he want
>
> [x,y,z] = meshgrid(-10:1:10,-5:1:5,-8:2:8);
> % this creates x,y and z 3-D arrays, x contains -10:1:10 replicated
> length(-5:1:5)xlength(-8:2:8) times, y contains -5:1;5 replicated .....
> c = x.^2+y.^2+z.^2;
> % c is now our function of 3 variables
> figure
> scatter3(x(:),y(:),z(:),5,c(:),'filled')
>
> which gives the attached result with fltk but does not work with gnuplot.
>
> Anyone has an idea if that can somehow work with gnuplot as well?

This is the error I get with gnuplot, same for you?

error: invalid value for color property "markerfacecolor"
error: called from:
error:   /usr/share/octave/3.6.1/m/plot/private/__scatter__.m at line
274, column 11
error:   /usr/share/octave/3.6.1/m/plot/private/__scatter__.m at line
211, column 13
error:   /usr/share/octave/3.6.1/m/plot/scatter3.m at line 68, column 11

I got this example to work with gnuplot using the following:

  cmap = colormap ();
  colors = cmap (fix (c(:).*(rows(cmap)-1)./max(c(:))) + 1, :);
  scatter3(x(:), y(:), z(:), 20, colors, 'filled');

Marker size 5 is invisible to me in gnuplot so I bumped it up to 20.

> Otherwise I file a bug.

Yes, please do.

-- 
mike