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## Copyright (C) 1996 John W. Eaton
##
## This file is part of Octave.
##
## Octave 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, or (at your option)
## any later version.
##
## Octave 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.
##
## You should have received a copy of the GNU General Public License
## along with Octave; see the file COPYING. If not, write to the Free
## Software Foundation, 59 Temple Place - Suite 330, Boston, MA
## 02111-1307, USA.
## usage: sombrero (n)
##
## Draw a `sombrero' in three dimensions using n grid lines. The
## function plotted is
##
## z = sin (sqrt (x^2 + y^2)) / (sqrt (x^2 + y^2))
## Author: jwe
function sombrero (n)
if (nargin != 1)
usage ("sombrero (n)");
endif
if (n > 1)
x = y = linspace (-8, 8, n)';
[xx, yy] = meshgrid (x, y);
r = sqrt (xx .^ 2 + yy .^ 2) + eps;
z = sin (r) ./ r;
mesh (x, y, z);
else
error ("sombrero: number of grid lines must be greater than 1");
endif
endfunction
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