Hello,
Can I know what these lines mean? It appears in the comsol window while running my project along with the “Stiff Chemistry Solver”. I wonder what it is because it doesn’t show in another project that I ran before.
Thanks a lot.
DLSODA is a FORTRAN library routine, it is the
Livermore Solver for Ordinary Differential Equations, with automatic method switching for stiff and nonstiff problems.
you can find out more about it here:
ODEPACK
The message above indicates a convergence failure - after 500000 steps, the solver gave up.
There is a control in the Chemistry pane, labeled
Maximum number of substeps in stiff solver.
The help text for that reads:
stiff_chem_max_steps
Maximum number of internal steps ODEPACK may use to integrate over the time interval. Leaving this value unspecified permits an unlimited number of steps. The stiff solver reports the number of cells that exceed the number of steps as 'incomplete'.
However, looking at the source code:
IF(STIFF_CHEM_MAX_STEPS == UNDEFINED_I) THEN
STIFF_CHEM_MAX_STEPS = 500000
If you don’t specify it, it seems to be getting forced to 500000, which matches the number in the message you specified.
You could try entering a larger number in that field.
Also, if you post your MFiX file (“Submit bug report”) we will be able to offer better help.
– Charles
2 Likes
Thanks a lot for your help.
I tried uploading the zip file which contains the mfix and other udf files but it says “Sorry, the file you are trying to upload is not authorized (authorized extensions: jpg, jpeg, png, gif, mp4, avi, wmv, zip, msh, stl, mfx, f, f90, tar, targz, py, webm, txt, yml).”
However, the steps for creating a bug report says:
Report a bug with MFiX. Include the following:
- Operating System
- MFiX version
- GUI or text (source code)
- Detailed description of the issue.
- Attach bug report zipfile if applicable (GUI)
- Attach .mfx file and UDFs if applicable (source)
But, unfortunately I can’t attach my zip file. What shall I do instead?
Thanks,
zip is on the list of allowed file types. Are you sure you were uploading the correct file? I’ll try it here and make sure it works.
- Charles
How big is your file? The size limit is 100MB.
1 Like
Dears,
Thank you all very much. I managed to upload the file now.
CH4.zip (52.1 MB)
If you run the file, it will show you the warning that I mentioned above:
Please help.
Thanks,
For future reference, don’t zip the output files (*.vtu, *.pvd, *.vtk, *.RES, .SP?). We are interested in the input files (.mfx and any *.f files modified).
1 Like
Have you found the solution to the problem yet?
I found similar message in the console window , the simulation did not stop but it became very slow.
This is an old topic. I don’t recall how I solved it. Can you upload your file? or copy the error message.
1 Like
The console window shows no errors, just some warning messages similar to that you posted previously, and the project does not stop but runs very slowly.
My project is a CFD-DEM case coupled with both heterogeneous and homogeneous reactions.
Can you help me? Thank you so much!
It’s not easy to see what’s going on from that photo of the screen. What happens after te DLSODA non-convergence messages? Can you upload a complete log file?