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[project @ 2007-11-26 19:16:07 by jwe]
author jwe
date Mon, 26 Nov 2007 19:16:07 +0000
parents 93c65f2a5668
children b93ac0586e4b
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7185:83cbff53bc96 7186:800f1fd3ffb8
18 18
19 ## -*- texinfo -*- 19 ## -*- texinfo -*-
20 ## @deftypefn {Function File} {} accumarray (@var{subs}, @var{vals}, @var{sz}, @var{fun}, @var{fillval}, @var{issparse}) 20 ## @deftypefn {Function File} {} accumarray (@var{subs}, @var{vals}, @var{sz}, @var{fun}, @var{fillval}, @var{issparse})
21 ## @deftypefnx {Function File} {} accumarray (@var{csubs}, @var{vals}, @dots{}) 21 ## @deftypefnx {Function File} {} accumarray (@var{csubs}, @var{vals}, @dots{})
22 ## 22 ##
23 ## Creates an array by accumulating the elements of a vector into the 23 ## Create an array by accumulating the elements of a vector into the
24 ## positions of defined by their subscripts. The subscripts are defined by 24 ## positions defined by their subscripts. The subscripts are defined by
25 ## the rows of the matrix @var{subs} and the values by @var{vals}. Each row 25 ## the rows of the matrix @var{subs} and the values by @var{vals}. Each row
26 ## of @var{subs} corresponds to one of the values in @var{vals}. 26 ## of @var{subs} corresponds to one of the values in @var{vals}.
27 ## 27 ##
28 ## The size of the matrix will be determined by the subscripts themselves. 28 ## The size of the matrix will be determined by the subscripts themselves.
29 ## However, if @var{sz} is defined it determines the matrix size. The length 29 ## However, if @var{sz} is defined it determines the matrix size. The length
44 ## 44 ##
45 ## An example of the use of @code{accumarray} is: 45 ## An example of the use of @code{accumarray} is:
46 ## 46 ##
47 ## @example 47 ## @example
48 ## @group 48 ## @group
49 ## accumarray ([1,1,1;2,1,2;2,3,2;2,1,2;2,3,2],101:105) 49 ## accumarray ([1,1,1;2,1,2;2,3,2;2,1,2;2,3,2], 101:105)
50 ## @result{} ans(:,:,1) = [101, 0, 0; 0, 0, 0] 50 ## @result{} ans(:,:,1) = [101, 0, 0; 0, 0, 0]
51 ## ans(:,:,2) = [0, 0, 0; 206, 0, 208] 51 ## ans(:,:,2) = [0, 0, 0; 206, 0, 208]
52 ## @end group 52 ## @end group
53 ## @end example 53 ## @end example
54 ## @end deftypefn 54 ## @end deftypefn
57 57
58 if (nargin < 2 || nargin > 6) 58 if (nargin < 2 || nargin > 6)
59 print_usage (); 59 print_usage ();
60 endif 60 endif
61 61
62 if (iscell(subs)) 62 if (iscell (subs))
63 subs = cell2mat (cellfun (@(x) x(:), subs, 'UniformOutput', false)); 63 subs = cell2mat (cellfun (@(x) x(:), subs, 'UniformOutput', false));
64 endif 64 endif
65 ndims = size (subs, 2); 65 ndims = size (subs, 2);
66 66
67 if (nargin < 3 || isempty (sz)) 67 if (nargin < 3 || isempty (sz))
68 sz = max (subs); 68 sz = max (subs);
69 if (isscalar(sz)) 69 if (isscalar(sz))
70 sz = [sz, 1]; 70 sz = [sz, 1];
71 endif 71 endif
72 else 72 elseif (length (sz) != ndims
73 if (length (sz) != ndims) 73 && (ndims != 1 || length (sz) != 2 || sz(2) != 1))
74 error ("accumarray: inconsistent dimensions"); 74 error ("accumarray: inconsistent dimensions");
75 endif
76 endif 75 endif
77 76
78 if (nargin < 4 || isempty (fun)) 77 if (nargin < 4 || isempty (fun))
79 fun = @sum; 78 fun = @sum;
80 endif 79 endif
84 endif 83 endif
85 84
86 if (nargin < 6 || isempty (isspar)) 85 if (nargin < 6 || isempty (isspar))
87 isspar = false; 86 isspar = false;
88 endif 87 endif
89 if (isspar) 88
90 if (ndims > 2) 89 if (isspar && ndims > 2)
91 error ("Can not have more than 2 dimensions in a sparse matrix"); 90 error ("accumarray: sparse matrices limited to 2 dimensions");
92 endif
93 endif 91 endif
94 92
95 [subs, idx] = sortrows (subs); 93 [subs, idx] = sortrows (subs);
96 if (isscalar (val)) 94 if (isscalar (val))
97 val = val * ones (size (idx)); 95 val = val * ones (size (idx));
98 else 96 else
99 val = val(idx); 97 val = val(idx);
100 endif 98 endif
101 cidx = find([true; (sum (abs (diff (subs)), 2) != 0)]); 99 cidx = find ([true; (sum (abs (diff (subs)), 2) != 0)]);
102 idx = cell (1, ndims); 100 idx = cell (1, ndims);
103 for i = 1:ndims 101 for i = 1:ndims
104 idx{i} = subs (cidx, i); 102 idx{i} = subs (cidx, i);
105 endfor 103 endfor
106 x = cellfun (fun, mat2cell (val(:), diff ([cidx; length(val) + 1]))); 104 x = cellfun (fun, mat2cell (val(:), diff ([cidx; length(val) + 1])));
107 if (isspar && fillval == 0) 105 if (isspar && fillval == 0)
108 A = sparse (idx{1}, idx{2}, x, sz(1), sz(2)); 106 A = sparse (idx{1}, idx{2}, x, sz(1), sz(2));
109 else 107 else
110 if (iscell (x)) 108 if (iscell (x))
111 ## Why did matlab choose to reverse the order of the elements 109 ## Why did matlab choose to reverse the order of the elements
112 x = cellfun (@(x) flipud(x(:)), x, 'UniformOutput', false); 110 x = cellfun (@(x) flipud (x(:)), x, 'UniformOutput', false);
113 A = cell (sz); 111 A = cell (sz);
114 elseif (fillval == 0) 112 elseif (fillval == 0)
115 A = zeros (sz, class(x)); 113 A = zeros (sz, class (x));
116 else 114 else
117 A = fillval .* ones (sz); 115 A = fillval .* ones (sz);
118 endif 116 endif
119 A (sub2ind (sz, idx{:})) = x; 117 A(sub2ind (sz, idx{:})) = x;
120 endif 118 endif
121 endfunction 119 endfunction
122 120
123 %!error (accumarray (1:5)) 121 %!error (accumarray (1:5))
124 %!error (accumarray ([1,2,3],1:2)) 122 %!error (accumarray ([1,2,3],1:2))