Disappearing Elements
Posted: Wed Jan 19, 2022 2:51 pm
I have been working with Vensim PLE and DSS happily for several years now.
I am now working on a mission critical model.
And suddenly, I encounter seemingly non-deterministic behaviour of Vensim.
Suddenly, various elements start disappearing.
We had been working on a model (see attachment "model 1"). Everything was fine.
Then we expand it slightly (see attachment "model 2").
While the model was open in Vensim, everything seemed fine. Elements we added were visible, they interacted correctly, and formulas could be edited as usual.
But as soon as we save the model, close Vensim, and open the model again, elements (seemingly randomly) start disappearing from all views - but not from the model logic!
So the result is that we now have working next versions, but they are virtually not editable and maintainable anymore, because you can't see the model structure anymore.
I tried to look into the text files to see what's happening. I clearly see that the disappeared variables are still in the model (formulas etc.), but that they are not contained in the lower part of the text files where the display coordinates etc. seem to be set.
To review the issue, take the two models attached. In "model 1", you can see the "Market Share competition" construct about in the center of the model, on the left of the "Headcount" graph. That variable is the source for the "Market_Share" graph at the bottom.
Then in "model 2", the said "Market Share competition" construct is completely gone, but the graph still works, and the variable is still in the model logic.
What is happening here?
To be clear: this is just one tiny example. When I was working on the model, I had expanded way beyond this, and had also continued working on the "broken", half disappearing model. Everything is logically working fine, but as said, we are running into more and more problems. By now, we are even seeing variable types change in the same way (e.g. flow becomes auxiliary).
I am using Vensim DSS 9.1.0 x64 on Windows.
I am now working on a mission critical model.
And suddenly, I encounter seemingly non-deterministic behaviour of Vensim.
Suddenly, various elements start disappearing.
We had been working on a model (see attachment "model 1"). Everything was fine.
Then we expand it slightly (see attachment "model 2").
While the model was open in Vensim, everything seemed fine. Elements we added were visible, they interacted correctly, and formulas could be edited as usual.
But as soon as we save the model, close Vensim, and open the model again, elements (seemingly randomly) start disappearing from all views - but not from the model logic!
So the result is that we now have working next versions, but they are virtually not editable and maintainable anymore, because you can't see the model structure anymore.
I tried to look into the text files to see what's happening. I clearly see that the disappeared variables are still in the model (formulas etc.), but that they are not contained in the lower part of the text files where the display coordinates etc. seem to be set.
To review the issue, take the two models attached. In "model 1", you can see the "Market Share competition" construct about in the center of the model, on the left of the "Headcount" graph. That variable is the source for the "Market_Share" graph at the bottom.
Then in "model 2", the said "Market Share competition" construct is completely gone, but the graph still works, and the variable is still in the model logic.
What is happening here?
To be clear: this is just one tiny example. When I was working on the model, I had expanded way beyond this, and had also continued working on the "broken", half disappearing model. Everything is logically working fine, but as said, we are running into more and more problems. By now, we are even seeing variable types change in the same way (e.g. flow becomes auxiliary).
I am using Vensim DSS 9.1.0 x64 on Windows.