Discussion Forum

I have also had the same problem. It began after I attempted to add another species (dependent variable) to a "transport of diluted species (chds)" model.


When I open the file, I get this error box:
"Invalid property value.
- Property: atolmethod
'Method' is an array of strings.
A string array with alternating references and values"


When I try to run the solver a Comsol error box appears that states:
"The following feature has encountered a problem:
-Feature: Compile Equations: Stationary (sol3/st1)
-Error: Invalid property value."

And a saved error appears in the model builder tree (Solver 1; Compile Equations: Stationary; Problem 1; Error 1):
"Invalid property value.
- Property: atol
'Tolerance' is an array of strings.
- : A string array with alternating references and values"

And another error box appeared:
"comsol found a model entity with name null that does not belong to a model"

Hi

when I got hat kind of errors, it was linked to an empty string in one of my data fields
or an operator with no selection

--
Good luck
Ivar

Thanks Ivar for the reply. That is what I initially thought, however when I checked every field, none were empty.

The error started when I added another species to the model. The error continued even when I deleted that new species, and the model is completely inoperable now. I tried recreating the model, and the same error appeared when adding another species. It may be a bug. I am currently talking with Comsol support. I will report back if a solution is found.

Hi

have you tried to do a "File - clear solution, - clear mesh - Reset model" then save and reopen COMSOL fresh ?
Sometimes it resets the model and corrects some wrong internal pointers


--
Good luck
Ivar

Thanks Ivar
I tried what you suggested. Clearing solution and mesh went fine, but when I ran "Reset History" the same error box that appears on opening the file popped up:

Invalid property value.
- Property: atolmethod
'Method' is an array of strings.
A string array with alternating references and values

Each time I run Reset History, it appears. I also tried creating a new Study and a new solver, running this new study resulted in this error:
"Found a model entity with name null that does not belong to a model".
and
Invalid property value.
- Property: atolmethod
'Method' is an array of strings.
- : A string array with alternating references and values

Thank you for your help.
Cheers,
Ryan

Hi

I'm afraid your model is somewhat corrupt, you could send it to "support" to find out and avoid that it happens again. In such cases, I remake my model from scratch, but that has not been necessary since I upgraded to 4.1

--
Good luck
Ivar

Thanks Ivar, I sent the model to support yesterday, after their initial suggestions did not help, and I am awaiting a reply. I will report back on the final verdict.
Cheers,
Ryan Renslow

The comsol support team has been very helpful. Here is the fix for this error:

"the problem is triggered by the fact that the Time-dependent solver
settings node cannot cope with new variable changes in the model. We have a
number of repeat models for this problem from before. But thanks for
sending us your model.
The only workaround I know is to delete the failing node and then add it
again. You have to manually re-edit changes you might have done to the
Time-dependent node. I have removed and added the node in the returned
version of your model." - Jacob Ystrom (Comsol Development)

I tested this by making another change to my working model (adding a new species to the dilute transport physics), I got the same errors again. Deleting the time dependent solver settings, and then adding them back, fixed the problem.

Easy, although annoying, workaround!

Hi

Indeed, this error/workaround was (is) very common in V4.0 and v4.0a, but I hadn't had it in v4.1 yet.

Now that "support" has received a good working/error example they will probably fix it for next release

--
Have fun COMSOLING
Ivar