Master commit of OpenFace.

matlab_version/face_validation/DeepLearnToolbox/util/allcomb.m

@@ -0,0 +1,87 @@
+function A = allcomb(varargin)
+% ALLCOMB - All combinations
+%    B = ALLCOMB(A1,A2,A3,...,AN) returns all combinations of the elements
+%    in A1, A2, ..., and AN. B is P-by-N matrix is which P is the product
+%    of the number of elements of the N inputs.
+%    Empty inputs yields an empty matrix B of size 0-by-N. Note that
+%    previous versions (1.x) simply ignored empty inputs.
+%
+%    Example:
+%       allcomb([1 3 5],[-3 8],[0 1]) ;
+%         1  -3   0
+%         1  -3   1
+%         1   8   0
+%         ...
+%         5  -3   1
+%         5   8   0
+%         5   8   1
+%
+%    ALLCOMB(A1,..AN,'matlab') causes the first column to change fastest.
+%    This is more consistent with matlab indexing. Example:
+%    allcomb(1:2,3:4,5:6,'matlab') %->
+%      1   3   5
+%      2   3   5
+%      1   4   5
+%      ...
+%      2   4   6
+%
+%    This functionality is also known as the cartesian product.
+%
+%    See also NCHOOSEK, PERMS,
+%    and COMBN (Matlab Central FEX)
+
+% for Matlab R13+
+% version 2.1 (feb 2011)
+% (c) Jos van der Geest
+% email: jos@jasen.nl
+
+% History
+% 1.1 (feb 2006), removed minor bug when entering empty cell arrays;
+%     added option to let the first input run fastest (suggestion by JD)
+% 1.2 (jan 2010), using ii as an index on the left-hand for the multiple
+%     output by NDGRID. Thanks to Jan Simon, for showing this little trick
+% 2.0 (dec 2010). Bruno Luong convinced me that an empty input should
+% return an empty output.
+% 2.1 (feb 2011). A cell as input argument caused the check on the last
+%      argument (specifying the order) to crash.
+
+error(nargchk(1,Inf,nargin)) ;
+
+% check for empty inputs
+q = ~cellfun('isempty',varargin) ;
+if any(~q),
+    warning('ALLCOMB:EmptyInput','Empty inputs result in an empty output.') ;
+    A = zeros(0,nargin) ;
+else
+    
+    ni = sum(q) ;
+    
+    argn = varargin{end} ;
+    ischar(argn)
+    if ischar(argn) && (strcmpi(argn,'matlab') || strcmpi(argn,'john')),
+        % based on a suggestion by JD on the FEX
+        ni = ni-1 ;
+        ii = 1:ni ;
+        q(end) = 0 ;
+    else
+        % enter arguments backwards, so last one (AN) is changing fastest
+        ii = ni:-1:1 ;
+    end
+    
+    if ni==0,
+        A = [] ;
+    else
+        args = varargin(q) ;
+        if ~all(cellfun('isclass',args,'double')),
+            error('All arguments should be arrays of doubles') ;
+        end
+        if ni==1,
+            A = args{1}(:) ;
+        else
+            % flip using ii if last column is changing fastest
+            [A{ii}] = ndgrid(args{ii}) ;
+            % concatenate
+            A = reshape(cat(ni+1,A{:}),[],ni) ;
+        end
+    end
+end