Multidimensional array stacking in Matlab

Question

Is there any short way to stack d outputs of ndgrid(x1,..,xd) into a d+1-dimensional array without using workarounds like cycles

cgrid=cell(1,d);
[cgrid{:}]=ndgrid(x1, x2, ... , xd);
agrid=zeros([d, size(cgrid{1})]);
for jj=1:d
    agrid(jj,:)=reshape(cgrid{jj},size(agrid(jj,:)));
end

or agrid=reshape(cell2mat(cellfun(@(c) c{:},cgrid)),[d, size(cgrid{1})])?

It seems to me that even simple operations with multidimensional arrays require lots of low-level commands.

Check this post. It might be helpful. stackoverflow.com/questions/14770081/… — Vikram
– Vikram, Commented Jun 20, 2013 at 1:24

Florian Brucker · Accepted Answer · 2013-06-20 06:30:14Z

1

You can use cat to do this:

buffer = cell(1, 3);
[buffer{:}] = ndgrid(1:10, 1:10, 1:10);
stacked = cat(length(buffer + 1), buffer{:});

Note that this is not exactly equivalent to the code you posted, since in this version the new index is in the last dimension (so stacked(:, :, :, i) is buffer{i}). You can use shiftdim to shift the dimensions around:

shifted = shiftdim(stacked, ndims(stacked) - 1);

Then squeeze(shifted(i, :, :, :)) is equal to buffer{i}.

answered Jun 20, 2013 at 6:30

Florian Brucker

10.6k6 gold badges56 silver badges92 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

xivaxy Over a year ago

Great! That's what I was looking for.

Collectives™ on Stack Overflow

Multidimensional array stacking in Matlab

1 Answer 1

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related