Graphics with gnuplot

Gnuplot is included by default in the vast majority of Linux distributions and is also more flexible in certain ways than GLE.

Example SConstruct, that follows the one in the GLE example: <python> from rsfproj import *

o1=-2 o2=-2 n1=41 n2=41 d1=0.1 d2=0.1

Flow('cosxpy',None,

   
   math o1=%g o2=%g n1=%d n2=%d d1=%g d2=%g
         output="cos(x1*x1+x2*x2)*exp(-0.1*(x1*x1+x2*x2))"
    % (o1,o2,n1,n2,d1,d2))

Result('cosxpy','grey color=j')

1. Prepare data for Gnuplot

Flow('cosxpy.z','cosxpy',

   
   disfil number=n col=%d | /bin/cat
    % n2)

1. Draw surfaces

Result('cosxpy_iso','cosxpy_bsurf.gp cosxpy.z',

     
     gnuplot | epstopdf --filter
     ,suffix='.pdf')

End() </python> On some systems, the actual executable is not gnuplot, but gnuplot-minimal. Another dependency is the epstopdf utility, which is a part of LaTeX installation, usually. Gnuplot scripts can render the isometric view in slightly different ways. Three examples of Gnuplot scripts, and the images produced by each, follow:

cosxpy_bsurf.gp:

set terminal postscript eps enhanced color
set output

set title "Hat function (3D)"
set xtics ("-2" 0, "-1" 10, "0" 20, "1" 30, "2" 40) out
set ytics ("-2" 0, "-1" 10, "0" 20, "1" 30, "2" 40) out
set ztics out
set zrange [-1.5:1.5]
set ztics 0.5
set xlabel "X-axis"
set ylabel "Y-axis"
set zlabel "Z-axis" offset 3,-1
set ticslevel 0.5
set palette defined (-1 "blue", 0 "white", 1 "red")
set pm3d at b
splot "cosxpy.z" matrix with lines notitle

cosxpy_cont.gp:

set terminal postscript eps enhanced color
set output

set title "Hat function (3D)"
set xtics ("-2" 0, "-1" 10, "0" 20, "1" 30, "2" 40) out
set ytics ("-2" 0, "-1" 10, "0" 20, "1" 30, "2" 40) out
set ztics out
set zrange [-1.5:1.5]
set ztics 0.5
set xlabel "X-axis"
set ylabel "Y-axis"
set zlabel "Z-axis" offset 3,-1
set ticslevel 0.5
set cntrparam levels auto 12
set contour base
set hidden3d offset 0
splot "cosxpy.z" matrix with lines notitle

cosxpy_surf.gp:

set terminal postscript eps enhanced color
set output

set title "Hat function (3D)"
set xtics ("-2" 0, "-1" 10, "0" 20, "1" 30, "2" 40) out
set ytics ("-2" 0, "-1" 10, "0" 20, "1" 30, "2" 40) out
set ztics out
set zrange [-1.5:1.5]
set ztics 0.5
set xlabel "X-axis"
set ylabel "Y-axis"
set zlabel "Z-axis" offset 3,-1
set ticslevel 0.5
set palette defined (-1 "blue", 0 "white", 1 "red")
set pm3d at bs
splot "cosxpy.z" matrix with pm3d notitle