Re: [Gnuplot-info] import external function via pipe?

[walter h. <wh...@bf...>]

Am 30.07.2012 22:42, schrieb Lev A. Melnikovsky:
> Hi,
> 
> the function I need to plot is a result of nontrivial computation (each data 
> point is obtained by solving an ODE). I have implemented it in C, but executing 
> the program with
> 
> real(system(sprintf("somecommand %f %f", x, y)))
> 
> once for each data point (this is a 3d surface) implies a significant overhead. 
> My program is statically linked, still this is too slow. I need grid data (to 
> create contours), so building the datafile is inefficient.
> 
> Ideally I'd like to see an option to open a pipe and write the arguments to it 
> and read the results from it. My program would be glad to work in this mode. Is 
> this possible?
> 
> I'm using Linux if this matters.
> 

I am not sure that i understand what you are trying to archive

Writing the data to a file and reading that as matrix should be pretty fast.
I assume you are aware that you can use binary data ? (http://gnuplot.sourceforge.net/demo_4.6/binary.html)

if you can write a gnuplot script you can uses popen() that should be
much better that system().

re,
 wh