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1 ## Copyright (C) 1993, 1994, 1995, 1996, 1997, 2000, 2005, 2006, 2007 |
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2 ## John W. Eaton |
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3 ## |
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4 ## This file is part of Octave. |
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5 ## |
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6 ## Octave is free software; you can redistribute it and/or modify it |
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7 ## under the terms of the GNU General Public License as published by |
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8 ## the Free Software Foundation; either version 3 of the License, or (at |
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9 ## your option) any later version. |
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10 ## |
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11 ## Octave is distributed in the hope that it will be useful, but |
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12 ## WITHOUT ANY WARRANTY; without even the implied warranty of |
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13 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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14 ## General Public License for more details. |
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15 ## |
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16 ## You should have received a copy of the GNU General Public License |
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17 ## along with Octave; see the file COPYING. If not, see |
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18 ## <http://www.gnu.org/licenses/>. |
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19 |
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20 ## -*- texinfo -*- |
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21 ## @deftypefn {Function File} {} sombrero (@var{n}) |
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22 ## Produce the familiar three-dimensional sombrero plot using @var{n} |
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23 ## grid lines. If @var{n} is omitted, a value of 41 is assumed. |
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24 ## |
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25 ## The function plotted is |
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26 ## |
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27 ## @example |
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28 ## z = sin (sqrt (x^2 + y^2)) / (sqrt (x^2 + y^2)) |
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29 ## @end example |
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30 ## @seealso{surf, meshgrid, mesh} |
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31 ## @end deftypefn |
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32 |
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33 ## Author: jwe |
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34 |
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35 function [x, y, z] = sombrero (n) |
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36 |
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37 if (nargin == 0) |
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38 n = 41; |
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39 endif |
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40 |
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41 if (nargin < 2) |
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42 if (n > 1) |
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43 tx = ty = linspace (-8, 8, n)'; |
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44 [xx, yy] = meshgrid (tx, ty); |
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45 r = sqrt (xx .^ 2 + yy .^ 2) + eps; |
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46 tz = sin (r) ./ r; |
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47 if (nargout == 0) |
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48 surf (tx, ty, tz); |
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49 box ("off"); |
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50 else |
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51 x = tx; |
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52 y = ty; |
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53 z = tz; |
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54 endif |
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55 else |
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56 error ("sombrero: number of grid lines must be greater than 1"); |
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57 endif |
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58 else |
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59 print_usage (); |
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60 endif |
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61 |
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62 endfunction |
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63 |
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64 %!demo |
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65 %! sombrero (); |
