Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.
Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.
LocalSelectionImpl/set error when using mphinterp
Posted 25 sept. 2012, 01:19 UTC−4 Interfacing Version 4.2a 2 Replies
Please login with a confirmed email address before reporting spam
I followed these steps:
1. Build a model.
2. Delete everything non-essential.
3. File -> Reset History
4. File -> Save As Model M-File...
5. Opened the m-file and added a few commands at the end to post-process the results. Including a call to mphinterp(..).
6. Ran it using a command like
comsolserver matlab "tbc_test, exit" -mlroot "C:\Program Files\MATLAB\R2012a" -np 6 -Dcs.ckl -nodesktop
7. Received the following error:
Error using com.comsol.model.impl.LocalSelectionImpl/set
Java exception occurred:
Exception:
java.lang.NullPointerException
(rethrown as com.comsol.util.exceptions.FlException)
Messages:
Stack trace:
at com.comsol.model.internal.impl.SelectionImpl.a(Unknown Source)
at com.comsol.model.internal.impl.SelectionImpl$a.a(Unknown Source)
at com.comsol.model.internal.impl.SelectionImpl$a.execute(Unknown Source)
at com.comsol.model.clientserver.ClientManagerImpl$e.call(Unknown Source)
at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Error in C:\Programs\COMSOL42a\mli\mphinterp.p>mphinterp (line 153)
Error in tbc_test (line 192)
[t, unit] = mphinterp(model, ...
Solution: to avoid this happening, a "Solution 1" under "Data Sets" under "Results" should still be present when saving the model as an M-file. I had deleted it before saving, and this, somehow, lead to the error message above.
How I figured it out:
• Started COMSOL with MATLAB, copied-and-pasted the contents of the M-file (except the function header) into it. This way I could experiment with mphinterp(..) without having to run the model from the command line every time I change something.
• Made a very simple model, and experimented with it. Figured out that the difference was the presence of "model.result.dataset.remove('dset1');" in the original M-file.
• This took a long time because of the unhelpful error message and no access to the source.
Hello Evgeni Sergeev
Your Discussion has gone 30 days without a reply. If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help.
If you do not hold an on-subscription license, you may find an answer in another Discussion or in the Knowledge Base.
Please login with a confirmed email address before reporting spam
It is simply that the following statement will be written into the .m file if there is no solution object, i.e. in the results tree (in the GUI).
model.result.dataset.remove('dset1');
But when I just right clicked results tree (in the GUI) and added a solution object, the following statement will be written into
model.result.dataset.create('dset1', 'Solution');
The latter supersedes the former and hence mpheval, mphinterp, etc. become active and errors such as 'unknown source', will not appear when run in matlab.
I am sure this may have been implicitly or explicitly stated in the manuals - but don't know where.
Therefore, I would like to thank you.
Suresh
Please login with a confirmed email address before reporting spam
Thanks for the clarification! And helping us save time!