limiting broadcast variable in a 3d block processing program

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tiwwexx 2022-10-4

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https://ww2.mathworks.cn/matlabcentral/answers/1817320-limiting-broadcast-variable-in-a-3d-block-processing-program

重新打开： tiwwexx 2024-3-8

I have some 3D or 4D arrays that I want to run a block processing on. To do this I create a cell object that I can call that returns matricies of position values.

For example, ind_object{1} = [1 2 3 ; 1 2 3; 1 2 3].

I then call this index object in a parfor loop to pull out blocks of my image (sz_block(n) is the size of the block, on this example [3,3,3])

parfor n=1:numel(index_object)
    block_im = pad_im(index_object{n}(1,1:sz_block(1)),index_object{n}(2,1:sz_block(2)),index_object{n}(3,1:sz_block(3)),:);
    out(n) = run_some_function(block_im);
end

The problem with this is that my "pad_im" array ends up being a broadcast variable and it's rather large 512x512x300 so the memory swapping really slows down the calculation.

Does anyone have a reccomendation to get rid of the broadcasting of the pad_im array?

Or does anyone know how other programs (like C/C++ or python) do n-dimensional block processing?

Thanks for the info!