No preference with name `tempfiles.saving.warnifoverwriteolder`

Hi,

First of all, thanks for sharing the great project MPh! I am looking forward to using it.

Today I tried to set it up on my system (Win 10 Enterprise, 64-bit). The installation via pip worked but I encountered some problems when using mph.start() as described in the tutorial.

Please find the log below - do you have an idea how to fix this issue?

This would be much appreciated, thank you.

Kind regards,

Philipp

---

In [2]: import mph

In [3]: client = mph.start(cores=1)
Traceback (most recent call last):
File "SourceFile", line 396, in com.comsol.model.util.ModelUtil.setPreference
File "SourceFile", line 619, in com.comsol.model.util.ServerModelUtil.setPreference
File "AccessController.java", line -2, in java.security.AccessController.doPrivileged 
File "SourceFile", line 622, in com.comsol.model.util.ServerModelUtil$19.run
File "SourceFile", line 2530, in com.comsol.nativeutil.preferences.Preferences.setPreference
Exception: Java Exception

The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "<ipython-input-3-9a0936dc3385>", line 1, in <module>
client = mph.start(cores=1)
File "C:\Users\p\Anaconda3\lib\site-packages\mph\session.py", line 103, in start
client = Client(cores=cores, version=version)
File "C:\Users\p\Anaconda3\lib\site-packages\mph\client.py", line 141, in __init__
java.setPreference('tempfiles.saving.warnifoverwriteolder', 'off')
com.comsol.util.exceptions.FlException: Exception:
com.comsol.util.exceptions.FlException: No preference with the name X was found#tempfiles.saving.warnifoverwriteolder
Messages:
No preference with the name X was found#tempfiles.saving.warnifoverwriteolder

[john-hen]

Hi Philipp. I also hope you can put this library to some good use. There is nothing you did wrong here, this is supposed to work.

However, while the documentation says that “versions from Comsol 5.1 onward are expected to work”, I’ve only ever tested with Comsol 5.5 and 5.6. And you’re probably using a somewhat older version. One that doesn’t have the tempfiles.saving.warnifoverwriteolder preference. Comsol does not seem to have a changelog that would document when they introduce new preferences, so I will only learn about that from bug reports such as this one.

Now this is easily fixable in library code. We can just ignore that error when the preference does not exist. I will fix that in the next release, which should be out by the end of the week if things go well.

The reason, by the way, why MPh tries to override some preferences is that we often run many simulations back to back. That’s in fact the raison d’être of MPh. And Comsol produces a lot of temporary files, in particular recovery files, that could easily fill up the hard drive, but serve little purpose when not using the GUI.

If you don’t want to wait until the new release, you can also comment out the offending line, any maybe the one after that too, right in the MPh code of your local installation, in the client.py file mentioned in the error message.

https://github.com/MPh-py/MPh/blob/ab2ddb7a396b154c876b9aaba0b36ca9c00abe98/mph/client.py#L141-L142

[john-hen]

Fixed in MPh 1.1.0, released today.