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1 ## Copyright (C) 1996, 1997 John W. Eaton |
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2 ## |
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3 ## This file is part of Octave. |
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4 ## |
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5 ## Octave is free software; you can redistribute it and/or modify it |
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6 ## under the terms of the GNU General Public License as published by |
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7 ## the Free Software Foundation; either version 2, or (at your option) |
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8 ## any later version. |
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9 ## |
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10 ## Octave is distributed in the hope that it will be useful, but |
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11 ## WITHOUT ANY WARRANTY; without even the implied warranty of |
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12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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13 ## General Public License for more details. |
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14 ## |
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15 ## You should have received a copy of the GNU General Public License |
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16 ## along with Octave; see the file COPYING. If not, write to the Free |
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17 ## Software Foundation, 59 Temple Place - Suite 330, Boston, MA |
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18 ## 02111-1307, USA. |
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19 |
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20 ## -*- texinfo -*- |
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21 ## @deftypefn {Function File} {} triu (@var{a}, @var{k}) |
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22 ## See tril. |
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23 ## @end deftypefn |
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24 |
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25 ## Author: jwe |
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26 |
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27 function retval = triu (x, k) |
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28 |
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29 if (nargin > 0) |
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30 [nr, nc] = size (x); |
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31 retval = zeros (nr, nc, class (x)); |
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32 endif |
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33 |
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34 if (nargin == 1) |
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35 k = 0; |
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36 elseif (nargin == 2) |
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37 if ((k > 0 && k > nc) || (k < 0 && k < -nr)) |
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38 error ("triu: requested diagonal out of range"); |
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39 endif |
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40 else |
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41 usage ("triu (x, k)"); |
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42 endif |
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43 |
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44 for j = max (1, k+1) : nc |
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45 nr_limit = min (nr, j-k); |
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46 retval (1:nr_limit, j) = x (1:nr_limit, j); |
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47 endfor |
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48 |
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49 endfunction |
