Converting a 3D Matrix to multiple 2D matrices
1 view (last 30 days)
Show older comments
I have a 3D matrix, 1000 x 1000 x 40
I want to convert this matrix to 40 different matrices, 1000 x 1000 each. I suppose I am asking for the inverse of repmat, however searches into that have not led to progress.
Any help is appreciated.
2 Comments
Athrey Ranjith Krishnanunni
on 17 Jan 2021
Edited: Athrey Ranjith Krishnanunni
on 17 Jan 2021
Something like this?
largeMatrix = randn(1000,1000,40);
smallMatrixArray = cell(40,1);
for iOuterDim = 1:40
smallMatrixArray{iOuterDim} = largeMatrix(:,:,iOuterDim);
end
Steven Lord
on 17 Jan 2021
I want to convert this matrix to 40 different matrices
Why? What benefit do you hope to gain by doing that instead of indexing into the array to retrieve the appropriate slice when needed?
A = reshape(1:(3*4*5), [3 4 5]);
A4 = A(:, :, 4)
What happens when or if you expand your problem sizes to an array of size 10000 in the third dimension? Your workspace would become awfully cluttered with ten thousand and one arrays in it.
Accepted Answer
Bruno Luong
on 17 Jan 2021
Edited: Bruno Luong
on 17 Jan 2021
Assuming A is array 1000 x 1000 x 40
C = num2cell(A,[1 2]);
2 Comments
Athrey Ranjith Krishnanunni
on 17 Jan 2021
You'll have to write
C = shiftdim(num2cell(A,[1 2]));
to get rid of the leading singleton dimensions, though.
Bruno Luong
on 17 Jan 2021
Well it is nicer but it is not requirement by OP.
C{k} still give the the kth matrix as requested.
More Answers (0)
See Also
Categories
Find more on Matrix Indexing in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!