Error for ViewingFactors with parallel computation

Discussion about building and installing Elmer
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kdarte
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Joined: 28 Nov 2022, 14:19
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Error for ViewingFactors with parallel computation

Post by kdarte »

Dear all,

I am currently not able to run my simulation with MPI. While it works just fine for the "FlowStepKe"-Tutorial,
for my project it crashes. As it involves radiation, ViewingFactors need to be calculated, and it seems as this causes the code to crash:
error_mpi.PNG
(31 KiB) Not downloaded yet
From "umf4sym" I'd guess that this happens in the linear solver. The simulation runs fine without the parallel solver.
Calling a serial instance of ViewingFactors also works.

I am not sure where to start for fixing the error, could anyone give me a hint?

I'm running this on a windows 10 machine with the recent mpi-version of elmer


Many thanks!
Last edited by kdarte on 29 Nov 2022, 10:42, edited 1 time in total.
kevinarden
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Re: Error for ViewingFactors with parallel computation

Post by kevinarden »

This usually means running out of memory, RAM, mpi generally takes more RAM because each processor needs a certain amount of RAM for each process. Try monitoring RAM usage during the runs.
kdarte
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Re: Error for ViewingFactors with parallel computation

Post by kdarte »

Thanks for the suggestion.

I am pretty sure that RAM is not the issue here - it hasn't even started to build up when the simulation crashes.

I can reproduce this with the Gui-Tutorial "radiation" - attached is my slightly adjusted version (essentially changing the parallel-solver settings)
Attachments
radiation_parallel.zip
(73.1 KiB) Downloaded 55 times
Last edited by kdarte on 29 Nov 2022, 10:43, edited 1 time in total.
kevinarden
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Re: Error for ViewingFactors with parallel computation

Post by kevinarden »

I have the same issue on Linux Mint. I faintly remember that calculation of view factors in parallel required precise control of the partitions so the the radiation boundary and the target boundary were in the same partition. This would not happen by default.
kdarte
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Re: Error for ViewingFactors with parallel computation

Post by kdarte »

Thanks a lot, I must have missed this thread... using

Code: Select all

ElmerGrid 2 2 %msh -connect 1 2 -partdual -metiskway %n
in the "Radiation" - Tutorial works just fine! If you have several seperate radiation regions, using the "connect" option for each region seems also to work.

For my setup with 6 radiation regions this results in the following decomposition:
dd.JPG
dd.JPG (42.41 KiB) Viewed 846 times
The results seems ok (heating up the parts within the holes by radiation)

heat_up.gif
heat_up.gif (209.07 KiB) Viewed 846 times
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