Ventana software support forum

Hey Tom and JJ, been doing a bit more work on this model since last post. I put in units ("widgets" meant to represent generic data) and quadruple subscripted to track Product (P) at Origins (O) through a Network (N) to Destinations (D). I actually submitted this as a paper (attached) to t...

Tom, Here's a better version where I've replaced the file references with ?Data (same data file)...all you need to do is modify that one pointer in the Model Settings. Also, replaced the Supply, Transit and Demand with Binomial distros controlled by *Prob sliders which adds some variability/reality....

Btw, do you know anyone at Sage Analysis Group? They're an MIT spin-off with offices in Boston, MA and Arlington, VA. I sent them a resume because they were advertising positions on the SD.org site. Hoping to talk to them about possibilities.

Tom, Turns out that the volume traversing the network can be homogenous and well-mixed for now (like your electon example). Otherwise, I think I'd need a seperate "network" for each To-From pair and control the network flow by aggegating that somewhere else in the model, like I suggested (...

Hey Tom, ABC and XYZ are different cities. It would be like NY,DC,Boston shipping to LA,SF,Seattle respectively. NY all has to go to LA and so on...but they can traverse the same connections on the way based on shortest path, available capacity, priority, etc. Perhaps it might be best to keep the su...

Greetings Tom (et al)...been a while since I've been doing SD, so I'm a little rusty. Hoping to get to the conference in Boston next year and catch up. Got a network modeling problem where Supply A,B,C needs to go to Demand X,Y,Z respectively. In between A,B,C origins and X,Y,Z destinations is a tra...

OK, partially answered my own question.

First, the number of runs should have been 8281 (91 * 91)...forgot about the endpoints.

Second, if I use Latin Grid, it works. But it always used to work with the Multivariate setting...did this change in Version 6.3?

I don't know what I'm doing wrong, but Sensitivity Runs are ignoring the Vector settings. For the settings in the attached screenshot, I should get 8100 runs (90 * 90)...but Vensim is only doing the number of simulations I have set in the field for running Monte Carlo analyses (currently 200). I'm u...

Is there any way to constrain the bounds of a lookup? What I'm trying to get is a "2-D" slice of a lookup table to find the area under a curve for different values of Xmin/Xmax AND Ymin/Ymax. I know this is possible with VECTOR LOOKUP AREA (as in the example) but LOOKUP AREA only allows co...

Problem solved!!!

When I replaced the 64-bit version of lpsolve55.dll with the 32-bit version (in the C:\lp_solve folder), it worked!

You may want to mention this in the setup instructions on the Workbench page.

Thanks,
Lou

BTW, I should have mentioned, I have a 64-bit OS...don't know if that makes a difference.

I deleted the files out of the other locations.

I'm running Version 6.0b. Maintenance ran out so I can't download 6.1 (yet).

Tom, I'm having some issues getting this running. I put the venextLP and venextLP_dp in the “C:\Users\SAO\Vensim\plugins” folder as shown. I put the lpsolve55.dll in the “C:\lp_solve” folder (and added it to my system path). I even put the dlls in the “C:\Users\SAO\Vensim\dll” and “C:\Windows\System...

Tom,

Awesome!! I actually did a search way back when and saw that solver too.

I'll explore and let you know if I have any issues implementing.

Cheers,
Lou

Hi guys, I'm getting an error with the latest download of Vensim when I use the SIMULTANEOUS function. After I select SIMULTANEOUS on an Auxiliary variable, it asks me if I want to add SIMUL TANEOUS to the model (the space is intentional, because that's what it asks). I have a feeling this is becaua...

Tom (et al),

Any thoughts lately about incorporating a linear program for optimizing allocations? Last I was grappling with this, the only option was the market clearing algorithms (built-in) or trying to trade data with Excel and using their LP.

Cheers,
Lou

I might be able to post a screenshot, but the application itself it's on a standalone system with high security. Is a screenshot sufficient?

Regards,
Lou

Hi there! This is my first time posting here...and first time developing a Sable interface in a while. I'm trying to use the SubScript Grid command to let the user edit an array of subscript constants during a run. The command brings up a nice, convenient grid that's easily editable...but when I cli...

Are there any examples of a "live" hotlink with Excel (as mentioned in the help)...using WM_DDE_REQUEST and WM_DDE_ADVISE commands? The DDE example files are "manual" in that you have to use buttons in Excel to stimulate the data transfer, run the simulation, etc. I want to be in...

Tom, Many thanks! I think I can use that construct in my model. In my other example, I tried mapping the Demander (D1, D2) and Supplier (S1, S2) variables to a single vector Alloc (A1-A4) as you suggested, but it still doesn't zero (reposted). However, I was actually successful at using a different ...

Thanks, but the example doesn't help because it doesn't make a many-to-many alloc (i.e. even if I use multiple products, they're still all commodities)...nor can I restrict the assignment (i.e. supplier 1 cannot supply to demander 2, etc.)...using, for instance, the :EXCEPT: function. Tom...I'm atta...

Just wanted to circle back around on this and ask if there's any way to do a many-to-many allocation but restrict what gets allocated to what (example models were posted back in Mar). The help makes mention that you can use multiple dimensional subscripts in the FIND MARKET PRICE construct (i.e. dem...

Actually, I'll ask a related question. Is this kind of allocation possible with a multi-dimensional FIND ZERO with constraints? For example, I want to minimize the difference between total demand and total supply, with the restrictions that Sum(Allocated[Demander!,Supplier]) <= Available Supply[Supp...

Actually, I tried that a while ago and got nowhere with it. I tried it again here...but wasn't sure about the order of the subscripts. In any case, neither way is working. If I make the subscripts (Supplier, Demander), I get an error. If I make them (Demander, Supplier) it runs, but the answers are ...

OK, here's a version of the model that I posted a while ago, which Tom helped me with. It's a lot further along now, but the basics with the allocation are still the same. I made two variables (Assignment PtoC, Assignment CtoR) that have the binary "restrictions". The Two-Way Allocation mo...