From help-request at octave dot org Tue Jan 18 12:53:50 2005
Subject: Re: Verilog - x and z values with octave load
From: Przemek Klosowski <przemek at jazz dot ncnr dot nist dot gov>
To: Octave Help <help at octave dot org>
Date: Tue, 18 Jan 2005 13:56:41 -0500 (EST)


   > Or does anyone have a better way of reading in values from a verilog/vhdl
   > simulation??
   > 
     ...
   directly with gnuplot, especially if you have gnuplot 4.0. You already know
   (almost) how to write the script if you have been using octave for plots,

The neat thing that's useful in Gnuplot is reading straight from a pipe
(except that it may or may not work on Windows, depending whether 
popen() works in the environment Gnuplot uses). You can do things like 

   plot "< awk '{print $1-1965, $2}' population.dat"

i.e. filter the data and plot the result without intermediate files.

This trick with magic filenames is also used in several other apps,
(Perl, xpdf, xmgr, etc), although they tend to use a different
notation ("cmd-pipe |" or "|cmd-pipe", depending on whether we want to
read or write data).

I don't think Octave allows magic filenames (please correct me if I am
wrong on that one). By the way, this can be simulated somehow with pipes
('mknod pipefile p'); just set up an infinite shell loop that keeps
re-processing your data:

 while :; do
    perl -pe 's/[xz]/NaN/g' verilog.out > pipefile;
 done &

This way, you can open 'pipefile' in Octave multiple times, and it will
always read the (processed) latest version of the output.

       p



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