Ventana software support forum

Actually they don't need to be shadow variables (unless appearing more than once on a diagram), but often they are used that way. Sounds like a good topic for a quick video clip ...

The syntax of a lookup is just like a function call, e.g. y = f(x), where f() is the lookup. A quick trip through the User Guide chapter linked above may help with this. In your case, you need a Lookup: dwg rate lookup = GET XLS LOOKUPS('ROI.xls','project' ,'E','F4' ) and an Auxiliary that uses the ...

The user guide has a chapter on lookups: http://www.vensim.com/documentation/usr08.htm

This is pointed at the wrong filename, but as soon as I change it to 'roi.xls' it works fine. An easy way to do that is to give it a query name flag, like '?roi', so that it'll ask you to locate the file on first use.

For maximum speed in the dll, you should run using the SYNTHESIM commands rather than ordinary simulations. http://www.vensim.com/documentation/25172.htm http://www.vensim.com/documentation/25531.htm http://www.vensim.com/documentation/25532.htm Turn AUTO off and use GO to launch simulations, after ...

Vensim is compatible with xlsx, so you should be able to use any version of Excel (I use 2010 regularly). If not, there's some peculiarity to your file or system (multiple versions of Excel running?). There shouldn't be any file name limitations either (other than the usual system-imposed limits). T...

You're right ... it looks like we broke it in the equation editor upgrade. There are two workarounds: - switch to the text editor view and manually delete the space in SIMUL TANEOUS, or - don't use the type dropdown in the equation editor; instead just type SIMULTANEOUS( ... ) in the equation field....

It's available now as an external function. Take a look, then we can talk ... http://vensim.com/workbench/

I think another thing that can cause the version -1 error is a missing resource file - be sure that you're running the version of the Vensim .dll that installs to your system, not a copy of the dll elsewhere.

Also, what version # are you using? I think the -1 error result actually indicates something other than a version mismatch, but I'd have to know what you're working with to be sure.

You need a separate Redistribution License to distribute the .dll, or have users install the Model Reader. We can give you a price quote if needed. It's possible to run a Vensim model from another Vensim model by creating an external function that calls the .dll. I've done it, and could probably fin...

It seems that what you're implying is that all of the steps can be completed in zero time, in which case it's not clear conceptually why you need any stocks. The missing component of this model is the time required to complete each step. For example, you have automated acceptance testing rate= integ...

Right. Things that respond instantaneously are not levels.

You might try working through something like the roadmaps series if this doesn't make sense.
http://clexchange.org/curriculum/roadmaps.asp

If you're using the .dll, you can use MEMFILE
http://www.vensim.com/documentation/25032.htm

What does modeFrontier provide that can't be done with the Vensim optimizers?

Right, forgot about that limitation. You could always upgrade ... You can write a simple equation in Excel to insert the needed punctuation, e.g., if you have row 1 & 2 1 2 3 4 0.1 0.2 0.3 0.4 write in cell A3, ="(" & A1 & "," & A2 & ")," Then fill r...

Here's how I'd modify the units to fix this: ************************************ Units changes from (<) Vensim Model Fish v2.mdl to (>) current model ************************************ Assumed Optimal Fish Density < Ton/m³ > Dmnl Change in Fleet < Fleet/Year > vessel/Year Effect of Fish Density o...

You can also use the "import vals" button in the "as graph" editor for the lookup to copy directly out of a spreadsheet. http://www.vensim.com/documentation/ref ... ort%2Bvals

I've recently added a number of models on topics in nonlinear dynamics to my library: http://models.metasd.com/bifurcations-from-strogatz-nonlinear-dynamics-and-chaos/ http://models.metasd.com/early-warnings-of-catastrophe/ There are some corresponding discussions on my blog: http://blog.metasd.com/...

When you say "data" here, do you actually mean the history of decisions made in a previous simulation, rather than external data?

They are uncorrelated, as are draws from any of the RANDOM functions. Completely uncorrelated white noise is actually not physically realizable, because it would have infinite power at high frequencies. So, you either need to ensure that your noise is sampled at some fixed interval, or implement a c...

Does this model run for you? (This is a modified version of what's in the help system.)

What version/hardware/OS are you on? [Never mind, I see this in your original post.]

Tom

Definitely reasonable - just tough for us to replicate unfortunately. Trying on this end too.

A typical thing to do would be to have a single auxiliary representing the coordinated action, and connect that to the two rates that affect separate levels.

Can you post the code you're using? .cin and data statements shouldn't normally interact.

You should be using INITIAL(GET TIME VALUE(2,0,10)) to avoid reinitializing the random stream at every time step. I don't think that's the issue though.

If you delete everything from the model but the NOISE SEED and the RANDOM instances, does it still crash? If so, could you share that portion?