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sparse function is intrisically slow?

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Jiangtao Lu
Jiangtao Lu on 7 May 2020
Commented: Yingzhi Liu on 19 Mar 2022
I am building the sparse matrix using the function sparse(I,J,V,N,N)
I, J and V are already a column vector. I checked previous questions, it seems already being the best way. But, it takes extreamely long time if the size goes to 1E5.
Any way out? Thanks!
James Tursa
James Tursa on 12 May 2020
OK. Are the values in the double vector stored in the same memory order as the sparse matrix columns? Can you give a small example of your indexing and values vector? I'm asking all of these questions to see if a mex routine could work for you.
Jiangtao Lu
Jiangtao Lu on 12 May 2020
Edited: Jiangtao Lu on 12 May 2020
I am not clear to that question. The calculation is like:
work.jacValueIndex = numC*(work.g(work.J)-1)+work.I;
jacValue = df(work.jacValueIndex)./dc(work.J);
jac = sparse(work.I,work.J,jacValue,numC,numC);
I attached an example of work and jacValue

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Answers (1)

Robert on 24 Dec 2020
I was able to speed my sparse matrix build for very large problems by using sparse2.m (mexFunction) from SuiteSparse.
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Yingzhi Liu
Yingzhi Liu on 19 Mar 2022
I downloaded SuiteSparse, but I don't konw how sould I do to use sparse2.m in matlab. Can you help me list the steps after downloaded SuiteSparse? Thanks.

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