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## Copyright (C) 1998-2003 Joao Cardoso.
##
## This program is free software; you can redistribute it and/or modify it
## under the terms of the GNU General Public License as published by the
## Free Software Foundation; either version 2 of the License, or (at your
## option) any later version.
##
## This program is distributed in the hope that it will be useful, but
## WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
## General Public License for more details.
##
## This file is part of plplot_octave.
function p9
global pl_automatic_replot
t = pl_automatic_replot;
pl_automatic_replot = 0;
as = autostyle;
autostyle ("off");
ls = legend;
legend "off"
step = 0.2;
x = -2:step:2;
y = -2:step:2;
[xx,yy] = meshgrid(x,y);
z = xx .* exp(-xx.^2 - yy.^2);
[gy, gx] = gradn(z,step,step);
title("Vector field example");
contour(x,y,z)
hold on;
arrows(yy,xx,gx./2,gy./2);
hold off
plflush;
legend(ls);
autostyle(as);
pl_automatic_replot = t;
endfunction
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