samer@4: function A=permutegroups(A,doms,perm)
samer@4: % permutegroups -  Reorder dimensions of array in groups
samer@4: % 
samer@4: % Like PERMUTE, PERMUTEGROUPS rearranges the dimensions of a 
samer@4: % multidimensional array in the same way that transpose swaps
samer@4: % the 2 dimensions of a matrix. However, rather than specifying
samer@4: % the permutation in terms of individual dimensions, the
samer@4: % dimensions are matched to a groups template and the then
samer@4: % the groups are permuted. Eg, suppose A is an array such that
samer@4: % the index domain size(A)=[6 3 4 7]. Now suppose the these
samer@4: % are grouped as [ [6 3] [4 7] ] and we wish to swap the groups.
samer@4: % Rather than saying
samer@4: %
samer@4: % 		permute(A,[3 4 1 2])
samer@4: %
samer@4: % we can say
samer@4: %
samer@4: %		permutegroups(A,{[6 3] [4 7]},[2 1])
samer@4: %
samer@4: % where the 2nd parameter specifies the two groups, and the third
samer@4: % indicates that we want to swap them. Actually, the numbers in the
samer@4: % group specification are not important - only the lengths of the
samer@4: % groups matters.
samer@4: %
samer@4: % Usage:	B=permutegroups(A,groups,perm)
samer@4: %
samer@4: %		A:		orginal array
samer@4: %		groups: list of array subdomains (ie sub-sequences of size(A))
samer@4: %				One of these may be nan, in which case, all remaining dims
samer@4: %				are assigned to that group.
samer@4: %		perm:  desired permutation of groups
samer@4: 
samer@4: a=0;
samer@4: dims=cell(size(doms));
samer@4: nanat=0;
samer@4: for i=1:length(doms)
samer@4: 	if isempty(doms{i}), dims{i}=[];
samer@4: 	else
samer@4: 		if ~isnan(doms{i})
samer@4: 			l=length(doms{i});
samer@4: 			dims{i}=a+(1:l);
samer@4: 			a=a+l;
samer@4: 		else
samer@4: 			nanat=i;
samer@4: 			dims{i}=a;
samer@4: 		end
samer@4: 	end
samer@4: end
samer@4: 
samer@4: if nanat>0
samer@4: 	gap=length(size1(A))-a;
samer@4: 	if gap>0, 
samer@4: 		dims{nanat}=dims{nanat}+(1:gap);
samer@4: 		for j=nanat+1:length(doms)
samer@4: 			if ~isempty(dims{j}), dims{j}=dims{j}+gap; end
samer@4: 		end
samer@4: 	else
samer@4: 		dims{nanat}=[]; 
samer@4: 	end
samer@4: else 
samer@4: 	gap=0;
samer@4: end
samer@4: 
samer@4: perm=cell2mat(dims(perm));
samer@4: maxdim=a+gap;
samer@4: if maxdim<1, perm(end+1)=1; end
samer@4: if maxdim<2, perm(end+1)=2; end
samer@4: 
samer@4: A=permute(A,perm);