What: gnuplot
 Where: http://www.gnuplot.info/
        http://gnuplot.sf.net/
        http://sf.net/projects/gnuplot/
        ftp://ftp.gnuplot.vt.edu/pub/gnuplot/
 Description: Gnuplot is a command-line driven interactive
        function plotting utility for UNIX, MSDOS, VMS,
        and many other platforms.  
 Updated: 12/2002
 Contact: See web site


People often ask about combinations of gnuplot
[ftp://ftp.gnuplot.vt.edu/pub/gnuplot]
and Tcl; in fact,
archives from [the comp.lang.tcl newsgroup] 
pertaining to gnuplot are quite extensive
[http://groups.google.com/groups?q=gnuplot+group%3Acomp.lang.tcl*&num=25&hl=en&scoring=d].
Perhaps the most impressive marriage of the two is
UniGNUPlot
[http://unicalculus.sourceforge.net/unignuplot/],
which makes for quick development of useful graphs:

"Just with simple 'click' and scroll bars,  
you have a good graphic in seconds, ready to insert
in the document what you want or directly to the printer..."

gnuplot handles real and complex data. 
Aside from plotting datasets gnuplot can handle functions i.e. f(x) = ax + bx² .. .
As an ecore gnuplot can fit functions to given data. 

----
[[
[Category Application] |
[Category Graphics] | [Category Plotting]
]]