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1 ## Copyright (C) 2001 Paul Kienzle <pkienzle@kienzle.powernet.co.uk> |
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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, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
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18 ## 02110-1301, USA. |
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19 |
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20 ## -*- texinfo -*- |
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21 ## @deftypefn {Function File} {@var{ind} =} sub2ind (@var{dims}, @var{i}, @var{j}) |
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22 ## @deftypefnx {Function File} {@var{ind} =} sub2ind (@var{dims}, @var{s1}, @var{s2}, @dots{}, @var{sN}) |
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23 ## Convert subscripts into a linear index. |
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24 ## @end deftypefn |
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25 ## |
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26 ## @seealso{ind2sub} |
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27 |
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28 ## Author: Paul Kienzle <pkienzle@kienzle.powernet.co.uk> |
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29 ## Adapted-by: jwe |
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30 |
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31 function ind = sub2ind (dims, varargin) |
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32 |
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33 if (nargin > 1) |
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34 if (isvector (dims) && round (dims) == dims) |
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35 nd = length (dims); |
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36 vlen = length (varargin); |
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37 dims(vlen) = prod (dims(vlen:nd)); |
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38 dims(vlen+1:nd) = []; |
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39 scale = cumprod (dims(:)); |
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40 for i = 1:vlen |
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41 arg = varargin{i}; |
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42 if (isnumeric (arg) && round (arg) == arg) |
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43 if (i == 1) |
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44 if (arg > 0 & arg <= dims(i)) |
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45 ind = first_arg = arg; |
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46 else |
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47 error ("sub2ind: index out of range"); |
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48 endif |
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49 else |
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50 if (prod (size (first_arg)) == prod (size (arg))) |
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51 if ((i > nd && arg == 1) || (arg > 0 & arg <= dims(i))) |
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52 ind(:) += scale(i-1) * (arg(:) - 1); |
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53 else |
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54 error ("sub2ind: index out of range"); |
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55 endif |
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56 else |
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57 error ("sub2ind: all index arguments must be the same size"); |
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58 endif |
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59 endif |
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60 else |
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61 error ("sub2ind: expecting integer-valued index arguments"); |
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62 endif |
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63 endfor |
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64 else |
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65 error ("sub2ind: expecting dims to be an integer vector"); |
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66 endif |
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67 else |
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68 usage ("sub2ind (dims, i1, i2, ..., iN)"); |
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69 endif |
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70 |
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71 |
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72 endfunction |
