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1 ## Copyright (C) 2004 David Bateman |
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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} {} rotdim (@var{x}, @var{n}, @var{plane}) |
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22 ## Return a copy of @var{x} with the elements rotated counterclockwise in |
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23 ## 90-degree increments. The second argument is optional, and specifies |
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24 ## how many 90-degree rotations are to be applied (the default value is 1). |
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25 ## The third argument is also optional and defines the plane of the |
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26 ## rotation. As such @var{plane} is a two element vector containing two |
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27 ## different valid dimensions of the matrix. If @var{plane} is not given |
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28 ## Then the first two non-singleton dimensions are used. |
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29 ## |
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30 ## Negative values of @var{n} rotate the matrix in a clockwise direction. |
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31 ## For example, |
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32 ## |
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33 ## @example |
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34 ## @group |
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35 ## rotdim ([1, 2; 3, 4], -1, [1, 2]) |
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36 ## @result{} 3 1 |
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37 ## 4 2 |
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38 ## @end group |
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39 ## @end example |
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40 ## |
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41 ## @noindent |
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42 ## rotates the given matrix clockwise by 90 degrees. The following are all |
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43 ## equivalent statements: |
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44 ## |
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45 ## @example |
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46 ## @group |
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47 ## rot90 ([1, 2; 3, 4], -1, [1, 2]) |
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48 ## @equiv{} |
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49 ## rot90 ([1, 2; 3, 4], 3, [1, 2]) |
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50 ## @equiv{} |
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51 ## rot90 ([1, 2; 3, 4], 7, [1, 2]) |
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52 ## @end group |
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53 ## @end example |
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54 ## @end deftypefn |
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55 ## @seealso{rot90, flipud, fliplr and flipdim} |
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56 |
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57 function y = rotdim (x, k, plane) |
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58 |
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59 if (nargin < 1 || nargin > 3) |
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60 usage ("rotdim (x, k, plane)"); |
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61 endif |
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62 |
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63 if (nargin > 1 && ! isempty(k)) |
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64 if (imag (k) != 0 || fix (k) != k) |
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65 error ("rotdim: k must be an integer"); |
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66 endif |
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67 else |
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68 k = 1; |
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69 endif |
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70 |
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71 nd = ndims (x); |
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72 sz = size (x); |
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73 if (nargin < 3) |
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74 ## Find the first two non-singleton dimension. |
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75 plane = []; |
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76 dim = 0; |
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77 while (dim < nd) |
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78 dim = dim + 1; |
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79 if (sz (dim) != 1) |
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80 plane = [plane, dim]; |
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81 if (length (plane) == 2) |
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82 break; |
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83 endif |
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84 endif |
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85 endwhile |
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86 if (length (plane) < 1) |
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87 plane = [1, 2]; |
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88 elseif (length (plane) < 2) |
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89 plane = [1, plane]; |
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90 endif |
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91 else |
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92 if (! (isvector (plane) && length (plane) == 2 |
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93 && all (plane == round (plane)) && all (plane > 0) |
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94 && all (plane < (nd + 1)) && plane(1) != plane(2))) |
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95 error ("rotdim: plane must be a 2 element integer vector defining a valid plane"); |
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96 endif |
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97 endif |
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98 |
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99 k = rem (k, 4); |
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100 if (k < 0) |
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101 k = k + 4; |
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102 endif |
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103 if (k == 0) |
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104 y = x; |
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105 elseif (k == 2) |
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106 y = flipdim (flipdim (x, plane(1)), plane(2)); |
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107 elseif (k == 1 || k == 3) |
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108 perm = 1:nd; |
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109 perm(plane(1)) = plane(2); |
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110 perm(plane(2)) = plane(1); |
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111 y = permute (x, perm); |
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112 if (k == 1) |
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113 y = flipdim (y, min (plane)); |
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114 else |
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115 y = flipdim (y, max (plane)); |
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116 endif |
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117 else |
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118 error ("rotdim: internal error!"); |
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119 endif |
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120 |
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121 endfunction |