matlab-grid-generator/bin/dimsum.m

function ds = dimsum(A,d,varargin);
% Matrix multiply a vector using a multi-dimensional array.
% This allows weighted summation in a 3-D/4-D arrays over
% a single index.
%
% >> size(T)
% ans =
%   128 64 10 23
% >> size(dz)
% ans =
%   10 1
% >> vintegral=dimsum(T,dz,3);
% >> size(vintegral)
% ans =
%   128 64 23

error(nargchk(2,3,nargin))

if size(d,2) ~= 1, error('Second argument must be a vector'); end

if nargin==3
  dim=varargin{1};
else
  if sum( size(A)==size(d,1) )==1
   dim=find( size(A)==size(d,1));
  else
   error('One and only one dimension must match unless you specify the dimension to sum')
  end
end

if size(A,dim) ~= size(d,1)
 error('Dimensions of matrix and vector do not match')
end

dims=[size(A) 1];
nd=size(d,1);
ip=[dim:ndims(A)+1 1:dim-1];
A=permute(A,ip);
A=A(1:nd,:);
ds=A'*d;

dims(dim)=1;
dims=dims(ip);
ds=reshape(ds,dims);
ds=squeeze(ipermute(ds,ip));
1	function ds = dimsum(A,d,varargin);
2	% Matrix multiply a vector using a multi-dimensional array.
3	% This allows weighted summation in a 3-D/4-D arrays over
4	% a single index.
5	%
6	% >> size(T)
7	% ans =
8	% 128 64 10 23
9	% >> size(dz)
10	% ans =
11	% 10 1
12	% >> vintegral=dimsum(T,dz,3);
13	% >> size(vintegral)
14	% ans =
15	% 128 64 23
16
17	error(nargchk(2,3,nargin))
18
19	if size(d,2) ~= 1, error('Second argument must be a vector'); end
20
21	if nargin==3
22	dim=varargin{1};
23	else
24	if sum( size(A)==size(d,1) )==1
25	dim=find( size(A)==size(d,1));
26	else
27	error('One and only one dimension must match unless you specify the dimension to sum')
28	end
29	end
30
31	if size(A,dim) ~= size(d,1)
32	error('Dimensions of matrix and vector do not match')
33	end
34
35	dims=[size(A) 1];
36	nd=size(d,1);
37	ip=[dim:ndims(A)+1 1:dim-1];
38	A=permute(A,ip);
39	A=A(1:nd,:);
40	ds=A'*d;
41
42	dims(dim)=1;
43	dims=dims(ip);
44	ds=reshape(ds,dims);
45	ds=squeeze(ipermute(ds,ip));