Ventana software support forum

Hi there,

I'd be grateful for links to past posts or direct advice.

1. I am working in Vensim Pro and have a model with 3 dimensions - Age, Operation, Health Trust. This comes to nearly 7000 specific dimensions in my model. Please don't comment on the appropriateness of these categories, it will eventually be a SD model theoretically, in terms of stocks and flows and feedbacks; just need the dimensions for client purposes as well.

2. I'm antiquated and working with linking my data via GET XLS DATA. It is crashing Vensim, in particular because I have 105 single-years of age. (Yes, I do sum up in subranges and can work with element, subranges, subscripts, and subscript mapping just fine. In fact, this is one of the reasons I've stuck with Vensim, finding R and Py to be a bit clunky in different ways, in a corporate context).

3. This GET XLS DATA is both for timeseries data, but it is actually important that I can choose a base year for different scenarios. The GET DATA AT TIME function crashes in particular when I tried to just get various base years out of the timeseries.

4. Even more humiliating, to import the data, I have 60 equations in one variable because I only know how to import this way (via the old .xls not even .xlsx)..... the first subscript is the 'master' and then i need to write new equations for each other pair of subscripts. Obviously I made 'age' the first subscript, or it would have been a lot more equations (age has the most elements).

5. Typically, I would run this model to import the data, and then save the .vdf file and create a new model for the real work. But I seem to be maxing out the potential of this method, and would love a cleaner way to import data as arrayed by my data scientist. CSV? How would it be formatted?

6. I do use .cin files for changing model constants and parameters. Just saying.

Any help much appreciated. Basically, I need to import a lot of data, and then it's a simple SD model, but with 7000 unique dimensions and (hopefully, eventually) calibrated to an imported timeseries so that I can initiate the model in equilibrium and then run scenarios where I disturb the equilibrium.

Thank you,
Sarah

I don't really follow any of this.

But I'd suggest CSV as the import type. You can have something like

time,,,,0,1,2,3,4,5,6
data,sub1,sub2,sub3,10,20,30,40,50,60,70

Thanks. So how does the import work? In an equation? Or via the sim control as a data source? In your example, is 'data' the variable name?

Is there a sample model in the documentation for this?

There's a chapter in the User Guide, https://www.vensim.com/documentation/21160.html

Last year's conference workshop is online https://vensim.com/conference/#using-data-in-vensim

If the Age x Operation x Health Trust matrix has a lot of empty elements, Ventity might be a good alternative.

For example, a while ago I prototyped a model of consumer products, with detail like Market (country) x Flavor x Size. Not every flavor x size is offered in every country, so the full matrix has a lot of empty cells. In array-based languages you have to simulate 0s for those. In Ventity, you can just create a product entity, and define it with data only for the ad hoc combination of attributes that actually exists.

If it's possible to replicate the crash in #3 with a reduced example (fake data if necessary), we'd love to track that down. Using xls could be a cause, just because it gets less use than xlsx these days. The function should work for either format. You can use the '?filename' trick to point to the file easily.

I think the issue you raise in #4 may be avoidable if you put cell addresses in an arrayed string function, but direct import from .csv or .tab is likely to be cleaner.

In the example, 'data' is a variable name.

There are a lot of possible layouts, including Tidy an relational, but typically something like this is easiest:
In the import dialog, you'll specify the "sub" columns as subscripts. The range names in the first row don't matter; only the element names below are used, and some can be blank for variables that don't have full detail.

Thank you for all the advice.

The biggest learning was to learn to use data import: Model>Import dataset....

- I note that the subscripts in the variable probably need to be in the same order as the column layout in the csv/excel/whatever.
- Once imported, the data still needs to be set as a .vdfx (or .vdf) run in the simulation control (advanced tab >> data sources) in order that it can be used to drive other variables.