Ventana software support forum

Not sure if you're making your Gantt charts in Vensim or with some other tool, but the simplest way to get the needed info would be something like the following: Suppose you keep track of task2 activity with a stock used as a switch, e.g. task2 has started = INTEG( task2 starting, 0 ) task2 starting...

If you want the value of x at some prior time, you can use DELAY FIXED to store it, e.g. y = x delayed * ... x delayed = DELAY FIXED( x, 10, x ) Vensim is causal, so there's no way to assign a value calculated at time t to a variable at a time less than t. That would amount to using information from...

I think this might be another thing that's not available in PLE, if that's what you're using.

See chapter 11 of the User Guide, e.g. http://www.vensim.com/documentation/20755.htm

This is not available in Vensim PLE, if that's what you're using. You can run games in existing models in the Model Reader though.

Didn't get your example, but here's one:

Yes - that's a run in gaming mode.

You need to make the variables that will change during the simulation into gaming variables, but using the GAME() function. Then start a game from the toolbar, rather than doing an ordinary run.

Yes. Again, you use the Comment tool to put a comment on the sketch. Give it whatever text and formatting you want (e.g, for a button, you might make the background color light gray, the shape a box, etc.) Put the label of the button in the Comment field. Then, near the middle of the dialog, choose ...

I'm not sure why we'd expect y=25 at time 5. With Euler integration and TIME STEP=1, the expected value is the cumulative flow prior to that point, i.e. 0+1+2+3+4 = 10. Making the time step approximately infinitesimal changes that to (5*5)/2 = 12.5. A good test here is to switch back to Euler integr...

To get a loop icon: - choose the Comment tool from the sketch toolbar - click in the middle of your loop - in the Comment dialog, choose Shape->Loop Clockwise or Loop Counter (top left) - either: - choose an icon from the dropdown menu in the Graphics area (bottom), or - give it a label like +/- or ...

The warning occurs because of the discontinuity at time 5 - a continuous method can't exactly integrate the discrete change. I think it's nothing to worry about in this case.

The behavior looks fine to me. What do you see as the problem?

In general you can model any kind of changing rate.

If you're using the .dll, you can call vensimbequiet() to suppress warning messages.

I think the first issue occurs because the big view is scaled to fit the screen, while the others are at 100%. So, regrettably, there probably isn't a way to get the arrowheads to match. The second is probably also exacerbated by scaling, but clearly it would help if we made the hot spot for arrow h...

Some of these things will take a while, but we're listening.

The other open question is whether you can call the (32 bit) dll from a VB script in a 64 bit app. Some 32/64 mixed environments don't work - for example, you can't call a 32 bit JNI dll from a 64 bit virtual machine in Java.

Tom

The answer partly depends on whether your model has units of years, with time step = 0.5, or months with time step = 6. If you're running in years, flows already have instantaneous annualized values, so you don't need to do anything unless you need to capture the actual reporting lag involved in ann...

We're working on it.

I don't think it'll help with memory, but if your arrays are sparse, VECTOR SELECT can help quite a bit with execution time.

Not sure why this is happening. The error files are unfortunately uninformative (at least to me). What operating system version are you using? One thing to try would be simply deleting (or renaming) the vensim.ini file mentioned in Tony's March 4 post (Vensim should recreate a fresh one on startup)....

This error is generated when you're using all the elements of an array, but not computing some of them. For example: myrange : mysubA, mysubB mysubA : (sa1-sa10) mysubB : (sb1-sb10) datavar[mysubA] := GET XLS DATA( ... ) auxvar[myrange] = 3*datavar[myrange] Notice that above, datavar is used with [m...

You may be limited by your largest array block - what number does it give with the "insufficient memory" error? (I'm guessing somewhere upward of 500 megabytes)

When does it happen?

It could be that your model is too big to be executed. Check Model>Settings>Info and see how many equations there are.

Tom

Is there a particular model that offends, that you can post?

194k should not be a problem - it might be a little slow, but not terrible - unless your time range is very large. For example, if your (FINAL TIME-INITIAL TIME)/TIME STEP is much greater than 10,000 that might be an issue. However, if the info says, "cannot be simulated," you have a synta...

Do you mean ranges with 3 elements (like city : boston, denver, chicago ) or variables with 3 ranges (like price[commodity,city,flavor])? If it's the latter, your model may be very large. A variable with 6 ranges will have N^6 elements, where N is the dimension of each range. If N=10, for example, y...

Noted. Thanks!

I haven't tried it, but it might be possible to store the decisions from a game in a .gin file, and then restart from the beginning and run up to the desired point using the .gin. Computationally wastefull, but maybe OK?

This kind of problem can be pretty messy (which is why it takes an iterative solver, as in Excel). It would be very natural to solve as a linear program. Mechanically, your model has 2 issues, fixed below. First, you're feeding in [problem,collect] tasks at the left, where it should probably be just...