[Trilinos-Users] VbrMatrix RAM usage

[Andrea Zonca]

Hi,
I have done more testing on my laptop, ubuntu with gcc 4.4.5 and trilinos
10.0.4 from ubuntu repository.
I create a map of 5 million rows linearly distributed on 2 processes.
At this point RAM usage is about 6MB per proc (using top).
Then I create a VBR matrix with this map specifying 1 blockentry per row.
Before inserting any data ram usage is 140 MB per processor.
Then I start looping on each row and I insert a block of 1x3 doubles.
15 millions double are about 115 MB (a numpy array of that size is 128 MB).
After this operation before fillcomplete, the RAM usage is 434 MB per proc,
about 500 after fillcomplete.
So about 7.5 times the data.
This doesn't look reasonable, would you have any suggestion on what could be
wrong?
My code is in a gist in one of the previous emails.
Thanks
Andrea Zonca
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