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1 ## Copyright (C) 2007 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 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} {} accumarray (@var{subs}, @var{vals}, @var{sz}, @var{fun}, @var{fillval}, @var{issparse}) |
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21 ## @deftypefnx {Function File} {} accumarray (@var{csubs}, @var{vals}, @dots{}) |
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22 ## |
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23 ## Create an array by accumulating the elements of a vector into the |
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24 ## positions defined by their subscripts. The subscripts are defined by |
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25 ## the rows of the matrix @var{subs} and the values by @var{vals}. Each row |
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26 ## of @var{subs} corresponds to one of the values in @var{vals}. |
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27 ## |
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28 ## The size of the matrix will be determined by the subscripts themselves. |
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29 ## However, if @var{sz} is defined it determines the matrix size. The length |
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30 ## of @var{sz} must correspond to the number of columns in @var{subs}. |
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31 ## |
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32 ## The default action of @code{accumarray} is to sum the elements with the |
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33 ## same subscripts. This behavior can be modified by defining the @var{fun} |
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34 ## function. This should be a function or function handle that accepts a |
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35 ## column vector and returns a scalar. The result of the function should not |
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36 ## depend on the order of the subscripts. |
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37 ## |
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38 ## The elements of the returned array that have no subscripts assoicated with |
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39 ## them are set to zero. Defining @var{fillval} to some other value allows |
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40 ## these values to be defined. |
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41 ## |
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42 ## By default @code{accumarray} returns a full matrix. If @var{issparse} is |
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43 ## logically true, then a sparse matrix is returned instead. |
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44 ## |
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45 ## An example of the use of @code{accumarray} is: |
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46 ## |
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47 ## @example |
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48 ## @group |
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49 ## accumarray ([1,1,1;2,1,2;2,3,2;2,1,2;2,3,2], 101:105) |
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50 ## @result{} ans(:,:,1) = [101, 0, 0; 0, 0, 0] |
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51 ## ans(:,:,2) = [0, 0, 0; 206, 0, 208] |
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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 |
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56 function A = accumarray (subs, val, sz, fun, fillval, isspar) |
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57 |
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58 if (nargin < 2 || nargin > 6) |
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59 print_usage (); |
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60 endif |
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61 |
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62 if (iscell (subs)) |
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63 subs = cell2mat (cellfun (@(x) x(:), subs, 'UniformOutput', false)); |
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64 endif |
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65 ndims = size (subs, 2); |
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66 |
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67 if (nargin < 3 || isempty (sz)) |
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68 sz = max (subs); |
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69 if (isscalar(sz)) |
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70 sz = [sz, 1]; |
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71 endif |
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72 elseif (length (sz) != ndims |
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73 && (ndims != 1 || length (sz) != 2 || sz(2) != 1)) |
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74 error ("accumarray: inconsistent dimensions"); |
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75 endif |
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76 |
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77 if (nargin < 4 || isempty (fun)) |
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78 fun = @sum; |
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79 endif |
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80 |
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81 if (nargin < 5 || isempty (fillval)) |
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82 fillval = 0; |
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83 endif |
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84 |
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85 if (nargin < 6 || isempty (isspar)) |
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86 isspar = false; |
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87 endif |
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88 |
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89 if (isspar && ndims > 2) |
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90 error ("accumarray: sparse matrices limited to 2 dimensions"); |
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91 endif |
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92 |
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93 [subs, idx] = sortrows (subs); |
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94 if (isscalar (val)) |
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95 val = val * ones (size (idx)); |
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96 else |
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97 val = val(idx); |
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98 endif |
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99 cidx = find ([true; (sum (abs (diff (subs)), 2) != 0)]); |
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100 idx = cell (1, ndims); |
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101 for i = 1:ndims |
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102 idx{i} = subs (cidx, i); |
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103 endfor |
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104 x = cellfun (fun, mat2cell (val(:), diff ([cidx; length(val) + 1]))); |
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105 if (isspar && fillval == 0) |
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106 A = sparse (idx{1}, idx{2}, x, sz(1), sz(2)); |
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107 else |
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108 if (iscell (x)) |
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109 ## Why did matlab choose to reverse the order of the elements |
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110 x = cellfun (@(x) flipud (x(:)), x, 'UniformOutput', false); |
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111 A = cell (sz); |
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112 elseif (fillval == 0) |
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113 A = zeros (sz, class (x)); |
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114 else |
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115 A = fillval .* ones (sz); |
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116 endif |
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117 A(sub2ind (sz, idx{:})) = x; |
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118 endif |
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119 endfunction |
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120 |
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121 %!error (accumarray (1:5)) |
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122 %!error (accumarray ([1,2,3],1:2)) |
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123 %!assert (accumarray ([1;2;4;2;4],101:105), [101;206;0;208]) |
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124 %!assert (accumarray ([1,1,1;2,1,2;2,3,2;2,1,2;2,3,2],101:105),cat(3, [101,0,0;0,0,0],[0,0,0;206,0,208])) |
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125 %!assert (accumarray ([1,1,1;2,1,2;2,3,2;2,1,2;2,3,2],101:105,[],@(x)sin(sum(x))),sin(cat(3, [101,0,0;0,0,0],[0,0,0;206,0,208]))) |
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126 %!assert (accumarray ({[1 3 3 2 3 1 2 2 3 3 1 2],[3 4 2 1 4 3 4 2 2 4 3 4],[1 1 2 2 1 1 2 1 1 1 2 2]},101:112),cat(3,[0,0,207,0;0,108,0,0;0,109,0,317],[0,0,111,0;104,0,0,219;0,103,0,0])) |
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127 %!assert (accumarray ([1,1;2,1;2,3;2,1;2,3],101:105,[2,4],@max,NaN),[101,NaN,NaN,NaN;104,NaN,105,NaN]) |
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128 %!assert (accumarray ([1 1; 2 1; 2 3; 2 1; 2 3],101:105,[2 4],@prod,0,true),sparse([1,2,2],[1,1,3],[101,10608,10815],2,4)) |
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129 %!assert (accumarray ([1 1; 2 1; 2 3; 2 1; 2 3],1,[2,4]), [1,0,0,0;2,0,2,0]) |
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130 %!assert (accumarray ([1 1; 2 1; 2 3; 2 1; 2 3],101:105,[2,4],@(x)length(x)>1),[false,false,false,false;true,false,true,false]) |
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131 %!test |
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132 %! A = accumarray ([1 1; 2 1; 2 3; 2 1; 2 3],101:105,[2,4],@(x){x}); |
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133 %! assert (A{2},[104;102]) |
