Opening a Stella model in Vensim

[martinmj]

I have tried to open a Stella model (.stmx) in Vensim and get a blank model. I don't getting any error messages and it creates a new model but there is nothing in it. Is there some way to verify that the Stella model is OK? I am using the latest PLE version.

[Administrator]

We would need the model to test with.

Unfortunately, even though they should be in Xmile format, they rarely are.

[Travis]

[quote=Administrator post_id=32131 time=1697468748 user_id=4547]
Unfortunately, even though they should be in Xmile format, they rarely are.
[/quote]

Curious: what do you mean they aren't in the Xmile format? Do you mean they aren't XML or something else?

[Administrator]

They rarely conform to the standard.

[martinmj]

These are the first few lines of the file. I can open it in a XML editor and everything is read seems OK. Can I send you the model to test?

<xmile version="1.0">
<header>
<smile version="1.0" namespace="std, isee" uses_submodels=""/>
<name>Detroit_Food_security_draft3</name>
<uuid>c6bb593c-90f9-4c03-9f04-25560a3af385</uuid>
<vendor>isee systems, inc.</vendor>
<product version="2.1.4" isee:build_number="2496" isee:saved_by_v1="true" lang="en">Stella Architect</product>
</header>

[Administrator]

Feel free to upload it. I can try opening it and see if I can get it to convert.

[Travis]

If Stella doesn't conform to the standard, you should tell them. Did you reach out to them when there was a problem? They have been supportive of the XMILE file format and the standards working group, so I think they would fix something.

Also, several other tools use the XMILE standard and seem interoperable, so maybe it has to do with Vensim's parser?

[martinmj]

Sorry for this newbie question. I am working with a model created by someone else and not sure I should make it public to the world. If I attach it here, who can access it?

[Administrator]

Sorry for this newbie question. I am working with a model created by someone else and not sure I should make it public to the world. If I attach it here, who can access it?

Anyone can access it here.

If it is sensitive and you have permission to share, you can email it to us at vensim@vensim.com

[Administrator]

If Stella doesn't conform to the standard, you should tell them. Did you reach out to them when there was a problem? They have been supportive of the XMILE file format and the standards working group, so I think they would fix something.

Also, several other tools use the XMILE standard and seem interoperable, so maybe it has to do with Vensim's parser?

It could quite possibly be the Vensim parser.

[martinmj]

I submitted the Stella model to vensim and they were able to read it in. The basic problem was that the creator of the model had broken it down into multiple 'sub-models' so the xml file had multiple <model> sections (which the conversion doesn't support yet). Also, most of the variables did not have any units. So the manual cleanup will be pretty involved but getting it read into Vensim was a huge help. Thanks.

[Travis]

Ventana/Admin – A pointer, in case you didn't know about this: There are GitHub repositories for sample models that try to help with reference implementations. You can find them in the test-models repo of SDX (SD Exchange, I think it stood for) https://github.com/SDXorg/ . Currently there are lots of MDL files for unit testing functions (like SDEverywhere would need) but there are some XMILE versions of the files too. Might be helpful to test Vensim's parse.

[Administrator]

Ventana/Admin – A pointer, in case you didn't know about this: There are GitHub repositories for sample models that try to help with reference implementations. You can find them in the test-models repo of SDX (SD Exchange, I think it stood for) https://github.com/SDXorg/ . Currently there are lots of MDL files for unit testing functions (like SDEverywhere would need) but there are some XMILE versions of the files too. Might be helpful to test Vensim's parse.

We did test with the reference models (although I don't recall where they came from).

[Travis]

Which models did you have that failed? Do they work now? Do you want me to see if they are valid in other tools?

[Administrator]

Which models did you have that failed?

Anything emailed to us (nothing we can share).

[Travis]

Do the models that failed still fail? Were they working in other applications?

I'm asking to get a sense of Vensim's XMILE support today and support in the future. If there are known issues it would be great to understand them better.

[Administrator]

Do the models that failed still fail?

No. If we are sent a model that is in "xmile" format and does not import, it's usually because it contains things where the XML tags contain isee::something. Obviously we cannot read isee specific things, but we can read these if we can identify what they are.

Were they working in other applications?

Such as?

I'm asking to get a sense of Vensim's XMILE support today and support in the future. If there are known issues it would be great to understand them better.

Vensim does read xmile format models. What it doesn't do is read the XML tags that are isee specific (unless we can read them easily and someone sends us an example).

[Travis]

Okay – that makes sense since the XMILE spec has "vendor-specific tags". Stella will have tags and Vensim could have tags for Vensim-only features too. Hopefully those extra tags are handled gracefully when being read by other applications –– that is the real key I would think. Import what can be imported and create a useful report of when couldn't be handled.

I haven't imported XMILE into Vensim recently, but I'll try sometime and report back with what I'm seeing.