transport step crash

6 years 1 month ago #256 by Philk
transport step crash was created by Philk

I'm running 1D, steady-state model, quite similar to the iCP-Benchmark 4 example, but a bit more complex and with a simulation time of 90 days.
In the beginning the simulation runs fine. But over time the calculation time for the transport step increases( seems to be a linear increase) and at some point the transport step crashes and i get the following error message( the complete message is attached):

Error in multiphysics compilation.
- Feature: Compile Equations: Time Dependent {time} (sol1/st1)

So i tried to let the Benchmark 4 example run over 90 days simulation time( i changed the simulation time and the OS-steps accordingly). And the same problem occured.

It seemed to me to be a memory problem( my computer has 16GB RAM) COMSOL has, maybe to much data the solver has to save, so i increased the maximum java heap space in the comsolserver.ini file.
I also varied some of the solver settings in comsol. (iterative solver, store solution out of core)
But that did not solve the problem.

I'm not sure what the exact problem is, so i wanted to ask if this kind of problem occured to someone else or did someone solve a similar problem already?

I'm looking forward to your answers/ideas
Best regards,

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6 years 1 month ago #257 by bshafei
Replied by bshafei on topic transport step crash
Hello Philipp,
It doesn't seem that heap memory space is causing the transport step failure otherwise JVM would have thrown an explicit exception message regarding to that. Particularly, for a 1D problem because of the small size of the built matrices, it doesn't seem to be the case. However if you wanna increase the dedicated heap memory space by JVM, you should do it through iCP batch file as well.
I would suggest you to create a checkpoint right before the time which transport step crashes in order to have an access to COMSOL and chemistry files in previous time step. Then you can investigate if the concentrations of species fall into a reasonable range.


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