Re: quiver question

[Paul Kienzle]

On Mar 22, 2005, at 10:01 PM, John W. Eaton wrote:

> On 22-Mar-2005, Paul Kienzle <address@hidden> wrote:
>
> | The quiver problem on the current Debian octave-forge
> | confuses me.
> |
> | The following does not work:
> |
> |       gplot M w v t ""
> |
> | The following works:
> |
> |       gplot '/tmp/oct-XXXXX' w v t ""
> |
> | where /tmp/oct-XXXXX contains the contents of the 4-column M.
>
> I tried saving some 4-column data to a file and using
>
>   plot 'foo.dat' w v t ""
>
> and gnuplot complained:
>
>   gnuplot> plot 'foo.dat' w v t ""
>                               ^
>            expecting 'lines', 'points', 'linespoints', 'dots', 'impulses',
>           'yerrorbars', 'xerrorbars', 'xyerrorbars', 'steps', 'fsteps',
> 	  'histeps', 'filledcurves', 'boxes', 'boxerrorbars', 
> 'boxxyerrorbars',
> 	  'vectors', 'financebars', 'candlesticks', 'errorlines', 
> 'xerrorlines',
>           'yerrorlines', 'xyerrorlines', 'pm3d'
>
> so what is a valid gnuplot plotting command that works so I can
> understand what you are trying to plot.

I'm trying to make a vector plot.  Here's more detail:

  [x,y] = meshgrid(1:2:20);
  u = sin(2*pi*x/10);
  v = sin(2*pi*y/10);
  M = [x(:), y(:), u(:), v(:)];

  system("rm /tmp/oct-*")
  gplot M w v t ""

This gives the error message:
         line 0: Not enough columns for this style

The following works (of course with Be4VTj replaced with whatever
was generated for your system):

  ls /tmp/oct-*
  gplot '/tmp/oct-Be4VTj' w v t ""


You may want to try 'w vec' or 'with vectors' or something like
that.

octave:26> OCTAVE_VERSION
OCTAVE_VERSION = 2.1.66

        G N U P L O T
        Version 4.0 patchlevel 0
        last modified Thu Apr 15 14:44:22 CEST 2004
        System: Linux 2.4.20-xfs


- Paul