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1 ## Copyright (C) 2001, 2003, 2004, 2005, 2006, 2007, 2008 Paul Kienzle |
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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 3 of the License, or (at |
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8 ## your option) 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, see |
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17 ## <http://www.gnu.org/licenses/>. |
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18 |
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19 ## -*- texinfo -*- |
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20 ## @deftypefn {Function File} {@var{ind} =} sub2ind (@var{dims}, @var{i}, @var{j}) |
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21 ## @deftypefnx {Function File} {@var{ind} =} sub2ind (@var{dims}, @var{s1}, @var{s2}, @dots{}, @var{sN}) |
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22 ## Convert subscripts into a linear index. |
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23 ## |
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24 ## The following example shows how to convert the two-dimensional |
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25 ## index @code{(2,3)} of a 3-by-3 matrix to a linear index. The matrix |
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26 ## is linearly indexed moving from one column to next, filling up |
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27 ## all rows in each column. |
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28 ## |
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29 ## @example |
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30 ## linear_index = sub2ind ([3, 3], 2, 3) |
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31 ## @result{} 8 |
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32 ## @end example |
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33 ## @seealso{ind2sub} |
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34 ## @end deftypefn |
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35 |
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36 ## Author: Paul Kienzle <pkienzle@kienzle.powernet.co.uk> |
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37 ## Adapted-by: jwe |
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38 |
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39 function ind = sub2ind (dims, varargin) |
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40 |
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41 if (nargin > 1) |
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42 if (isvector (dims) && all (round (dims) == dims)) |
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43 nd = length (dims); |
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44 vlen = length (varargin); |
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45 dims(vlen) = prod (dims(vlen:nd)); |
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46 dims(vlen+1:nd) = []; |
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47 scale = cumprod (dims(:)); |
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48 for i = 1:vlen |
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49 arg = varargin{i}; |
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50 if (isnumeric (arg) && isequal (round (arg), arg)) |
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51 if (i == 1) |
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52 if (all (arg(:) > 0 & arg(:) <= dims(i))) |
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53 ind = first_arg = arg; |
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54 else |
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55 error ("sub2ind: index out of range"); |
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56 endif |
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57 else |
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58 if (size_equal (first_arg, arg)) |
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59 if ((i > nd && arg == 1) || all (arg(:) > 0 & arg(:) <= dims(i))) |
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60 ind += scale(i-1) * (arg - 1); |
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61 else |
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62 error ("sub2ind: index out of range"); |
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63 endif |
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64 else |
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65 error ("sub2ind: all index arguments must be the same size"); |
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66 endif |
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67 endif |
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68 else |
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69 error ("sub2ind: expecting integer-valued index arguments"); |
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70 endif |
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71 endfor |
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72 else |
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73 error ("sub2ind: expecting dims to be an integer vector"); |
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74 endif |
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75 else |
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76 print_usage (); |
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77 endif |
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78 |
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79 |
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80 endfunction |
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81 |
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82 # Test input validation |
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83 %!error <sub2ind: expecting dims to be an integer vector> sub2ind([10 10.5], 1, 1); |
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84 %!error <sub2ind: expecting integer-valued index arguments> sub2ind([10 10], 1.5, 1); |
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85 %!error <sub2ind: expecting integer-valued index arguments> sub2ind([10 10], 1, 1.5); |
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86 |
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87 # Test evaluation |
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88 %!shared s1, s2, s3, in |
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89 %! s1 = [ 1 1 1 1 ; 2 2 2 2 ]; |
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90 %! s2 = [ 1 1 2 2 ; 1 1 2 2 ]; |
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91 %! s3 = [ 1 2 1 2 ; 1 2 1 2 ]; |
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92 %! in = [ 1 101 11 111 ; 2 102 12 112 ]; |
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93 %!assert (sub2ind([10 10 10], s1, s2, s3), in); |
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94 %!shared |
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95 |
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96 # Test low index |
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97 %!assert (sub2ind([10 10 10], 1, 1, 1), 1); |
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98 %!error <sub2ind: index out of range> sub2ind([10 10 10], 0, 1, 1); |
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99 %!error <sub2ind: index out of range> sub2ind([10 10 10], 1, 0, 1); |
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100 %!error <sub2ind: index out of range> sub2ind([10 10 10], 1, 1, 0); |
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101 |
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102 # Test high index |
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103 %!assert (sub2ind([10 10 10], 10, 10, 10), 1000); |
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104 %!error <sub2ind: index out of range> sub2ind([10 10 10], 11, 10, 10); |
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105 %!error <sub2ind: index out of range> sub2ind([10 10 10], 10, 11, 10); |
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106 %!error <sub2ind: index out of range> sub2ind([10 10 10], 10, 10, 11); |
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107 |
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108 # Test high index in the trailing dimensions |
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109 %!assert (sub2ind([10], 2, 1, 1), 2); |
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110 %!error <sub2ind: index out of range> sub2ind([10], 1, 2, 1); |
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111 %!error <sub2ind: index out of range> sub2ind([10], 1, 1, 2); |
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112 %!assert (sub2ind([10 10], 2, 2, 1), 12); |
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113 %!error <sub2ind: index out of range> sub2ind([10 10], 2, 1, 2); |
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114 %!error <sub2ind: index out of range> sub2ind([10 10], 1, 2, 2); |
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115 |
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116 # Test handling of empty arguments |
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117 %!assert (sub2ind([10 10], zeros(0,0), zeros(0,0)), zeros(0,0)); |
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118 %!assert (sub2ind([10 10], zeros(2,0), zeros(2,0)), zeros(2,0)); |
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119 %!assert (sub2ind([10 10], zeros(0,2), zeros(0,2)), zeros(0,2)); |
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120 %!error <sub2ind: all index arguments must be the same size> sub2ind([10 10 10], zeros(0,2), zeros(2,0)); |
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121 |
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122 # Test handling of arguments of different size |
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123 %!error <sub2ind: all index arguments must be the same size> sub2ind([10 10], ones(1,2), ones(1,3)); |
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124 %!error <sub2ind: all index arguments must be the same size> sub2ind([10 10], ones(1,2), ones(2,1)); |
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125 |
