Re: Speeding Up gnuplot Interface with Binary Data

[Daniel J Sebald]

Ben Abbott wrote:
> On Oct 7, 2008, at 2:56 AM, Daniel J Sebald wrote:
>
> > John,
> >
> > Attached is a patch using gnuplot's binary data input feature rather  
> > than ASCII data fifteen characters wide.  It does appear to speed up  
> > drawing a fair amount.  Less data is transmitted through the pipe,  
> > gnuplot doesn't have to input data as formated, and as I see it  there 
> > is no need for handling NaN in a special way (it is just  another 
> > value in IEEE format).
> >
> > Let me know what you think.
> >
> > Dan
>
>
> Dan, great idea.
>
> Is it possible to optionally produce the ascii so that it may be saved  
> to a file for examination?
>
> For example, the syntax below was used to save the gnuplot stream and  
> examined to determine why color interpolation was not working properly.
>
>     [... plot commands ...]
>     drawnow ("x11", "/dev/null", false, "debug.gp")
>
> The plot can then be produced from a shell by
>
>     gnuplot --persist debug.gp

Would a conditional test on the gnuplot version number and "/dev/null" 
somewhere help?  It is easy enough to keep the old code around.  John would know better 
than I how to implement that.  The __go_drawnow__() is a builtin function so rather than 
passing an additional argument into one of the graphics functions, perhaps there is a 
better behind-the-scenes approach.  I think it would have something to do with the code 
hunk from graphics.cc:

                          if (h.ok ())
                            {
                              graphics_object go = gh_manager::get_object (h);

                              go.get_backend ()
                                .print_figure (h, term, file, mono, debug_file);
                            }
                          else

Dan