Discussion Forum

Hi Jiuan,

you can stop your simulation and after checking the results you are able to continue the simulation (study -> continue). Other ways are defining of probes or showing plots during simulation!

Michael

Hi Machael, thanks for your help.

Hi Michael,

I find that after I stop the calculation then click Continue, COMSOL will start the calculation from the beginning.

Do you have the same observation?

Thanks.

Hi,

I saw this post from a few months ago and was wondering the same thing. My concern is not even checking anything in the middle, but simply pausing so that I can close and take home my computer and continue running from home without the past day of running being for nothing. I see the little red X which cancels the computation but I don't see a stop or pause which will allow it to continue. Did you ever find such a thing? Where in the interface would I find that? Thanks!

Shoshana

Hello Shoshana

I asked COMSOL support about the exact same thing. The answer I got was "yes, that is possible".

1) During the calculation, got to the "Progress" tab. It's in the lower part of the screen, right underneath the graphics window.

2) Click the "Stop" buttons.

3) Wait for the calculation to stop.

4) When the calculation has stopped, you get an error message about the calculation being interrupted. Click "Ok".

5) Save the file. You can now close COMSOL.

6) Later, open the file. Right click the relevant "Study" and select "Continue". The should be it.

I have not tried it myself yet, so please test it first on something inconsequential, and please post whether it worked or not.

Best regards
Lars

Hi Lars,

Thanks for your response! Interesting, it's very similar to what to do if it crashes in the middle, minus the recovery file. I haven't tried it yet but that's a good idea to test it on something small and simple to check that it works. I will let you know how it goes.

Thanks again!
Shoshana

Any conclusions whether it actually worked?

I stopped the solution (Interrupted) and when used Continue, the solution restarted from the beginning and it was not continued from where it stopped. Maybe this needs to be done differently.

You can stop the solver from progress bar by clicking on STOP on corresponding to running current solver step. Once you check the results, the solver can resume from the continue button from the study.

If your really want to monitor particular variable, plot it while solving functionality, and select the solution from the solver steps.

Sohan

I have encounter the same problem, and I tried many methods, but they didn't work. Have you solved the problem?

I stopped the solution and then used Continue, but the calculation restarted from the very beginning and it was not continued from where it stopped. Do you know how to solve this problem?

I stopped the solution and then used Continue, but the calculation restarted from the very beginning and it was not continued from where it stopped.
And a model of COMSOL 5.0, the ground_heat_recovery.mph in "models\Heat_Transfer_Module\Buildings_and_Constructions" also have the same problem.
I really don't know how to solve the problem. Do you ever encouter such problem?

Hi,

I think that what you report here comes from the fact that the COMSOL Multiphysics solvers can only continue from stored solutions. So even if the computation has been going on for quite some time and several time steps have been taken by the solver, the time stepping may not have reached the first output time. When stopped, the solver only returns the output times that have passed (logged as "out" in the Log window). When the solver continues, it will start from the last such output time.

Best regards,
Magnus Ringh, COMSOL

My experience:

I was ultimately unsuccessful in continuing a parametric sweep in a structural mechanics study. I stopped the computation, checked a few things, pressed 'Continue', and the calculation was resumed. However, when I stopped again, closed the file and the application, and came back the next day, I was not successful in continuing.

Possible contributing factor:

When I attempted to reload the file, the application failed to find a "CAD-IMPORT" license, even though the structure had been drawn initially in COMSOL, without being imported. So, the structure was regenerated within the application.

Suggestions, given and sought:

My suggestion to the authors is, the study should have restarted successfully.

Suggestions on how to proceed with continuing, welcome.

Hi David,

When your license includes the CAD Import Module, as seems to be the case for you, there are two geometry kernels available: the "COMSOL kernel" and the "CAD kernel" (which comes with the CAD Import Module, Design Module and "LiveLink for CAD" products ). You can see which kernel is used by a particular file under the Settings window for the Geometry branch (under "Geometry representation").

From your message, it seems that when you set up the model initially you used the CAD kernel, which is why when you tried to open the file later the software looked for the CAD Import Module. The crucial point here is that even if a geometry is drawn entirely with operations available in the core COMSOL Multiphysics (no import, no cap faces, no special operations from the Design Module) it is possible that it may require the CAD kernel to analyze it, i.e. that creating that geometry with the COMSOL kernel would fail (For instance, an intersection between complex shapes may not possible for the COMSOL kernel to compute, or something like that). Those situations are quite rare, but they can happen. In many cases, it is possible to convert a geometry from the CAD kernel to the COMSOL kernel (assuming of course that it does not involve an import step, cap faces, or one of the Design Module's special operations). The COMSOL kernel will give it a good try and let you know if it manages to do it.

Note that you can set which kernel the software should use when starting a new file as well as what the software should do when opening an existing file under File > Preferences > Geometry.

Jeff

I stopped the solution (Interrupted) and when used Continue, the solution restarted from the beginning and it was not continued from where it stopped. Maybe this needs to be done differently.

Hello,
Please note the if the solver shows it just start it doesn't mean that it is starting from the first calculation. In other words, if it shows that it is in the 4% of the calculation, it just means that it is in the 4% of what is left to calculate. This means that if you stopped the solver in the 45% of the calculation and saved the file and then restarted the calculation (By clicking " continue" in the study) and then 4% appears in the progress bar, it means that he has already calculated 4% of the 55% that remains to calculate.
This that I'm saying can be easily checked if you plot the stored results meanwhile you solve your model. When you re-start the calculation, COMSOL will plot the timestep in which he is solving which will correspond to the one of the 45% in this hypothetic case.

Enjoy COMSOLING ! (By stopping your simulation and continuing it afterwards at different place :) )