[petsc-users] Question-Memory of matsetvalue

[김성익]

Hello,



I have a question about memory of matsetvalue.

When I assembly the local matrix to global matrix, I’m just using
matsetvalue.
Because the connectivity is so complex I can’t use matsetvalues.

I asked this question because I was curious about how ram memory is
allocated differently for the two simtuations below.



First situation.

The local matrix size is 24 by 24. And the number of local matrix is
125,000.

When assembly procedure by using matsetvalue, memory allocation does not
increase.
So I just put Matassemblybegin and matassemblyend after all matsetvalue.



Second situation.

The local matrix size is 60 by 60. And the number of local matrix is 27,000.

When assembly procedure by using matsetvalue, memory allocation does
increase.

So I just put Matassemblybegin and matassemblyend after each local matrix
assembly.
This did not increase the memory further..



Why this situation is happen?

And is there any way to prevent the memory allocation from increasing?







Thanks,

Hyung Kim
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