Vensim in Spatial Models

[PeterB]

Dear Colleagues,

I'm planning to build a grid based spatial model where a VENSIM model is simulating the processes happening on each cell and where a superordinate software is taking care for managing the exchange between cells. The number of cells will be to high for just solving this in Vensim with a two-dimensional array.

There is a free software 'Spatial Modeling Environment' SME (http://www.uvm.edu/giee/SME3/) which seems to be a solution.

I would like to ask if any of you already tried to combine SME with VENSIM before, and if so, how it worked. Is there published work existing about that?

I would also appreciate hints for other alternatives for putting Vensim models in a large grid-based structure.

Greetings and thanks in advance
Peter

[bob@vensim.com]

A grid is just a 2 dimensional array and you might look at VECTOR SELECT as a means of managing cross boundary migration. The simple heat transfer example in the documentation would apply.

I don't know anything about SME unfortunately.

[PeterB]

Thanks Bob!

Actually, for testing purposes, I have built a solution in Vensim which works perfectly for, say, 400 grid cells. It's based on a two-dimensional array and the exchange between cells is managed by using mapped subscripts.

The 'big' model, however, should cover as many as 60.000 grid cells (100 x 600). I never tried this size in Vensim. Should I?

Greetings
Peter

[bob@vensim.com]

100 x 600 should not be too bad if the model (or at least the part with grid components) is small - say 10-20 variables. 20 variabls x 60K gives 1.2 million so you will probably want to use a save list but it should be manageable. If the model is bigger things will get pretty slow.