Ventana software support forum

Thanks Tom. If you're ever looking for a beta tester, keep me in mind.
Meanwhile, I will stop holding my breath.

[ ] Almost done.
[ ] In the works.
[ ] We're thinking about it
[ ] It's complicated.
[ ] No way, don't hold your breath

Please check the appropriate box.
Thanks!

Yes, I think it's the Ignorance stock that's particularly problematic. It's defined as Obsolescence-Learning, and both of those are rates/year, so it has to be a stock of rates, which gets very weird very quickly. I can conceptualize Knowledge as a "thing" that can be acquired or depleted,...

Datasets include output data only. That's the little nugget of info I was missing.
I've been thinking of upgrading to Pro for the sensitivity analysis. This could be another good reason to consider it.
Thanks again Tom!

Synthesim is great and I've been using it. This is more an issue of getting back to a starting point after changing a model and running it under different names. For example, here is a snapshot of my Control Panel: vensim-control-panel.jpg To create a graph comparing the effects of different values ...

I'm using VensimPLE. Suppose I have a model that includes 6 variables, a thru f, all constants. I use them to create some Custom Graphs. I populate each constant with a value. Now I want to save this model as my default, so I set the Run Name to 'default' and run it. Now I play around with my variab...

Thanks Tom, for your patience in helping me work thru this. I was able to use your suggestion to get down to 2 unit errors. I did make Knowledge and Ignorance dimensionless, and Learning and Obsolescence 1/Year, and that got rid of some of the EXP and LOG errors. I was also able to put the Environme...

Knowledge and Ignorance are key stocks in the model. Their "unit" is actually a little obscure in the InsightMaker model and the 2021 paper. Both basically represent the amount of technology in the system. "Knowledge" is the amount of useful technology and "Ignorance" i...

I recently took on the task of converting an interesting model written in InsightMaker to VensimPLE. After various fits and starts, I succeeded in getting the Vensim model to exactly replicate all the equations, parameters, and output in the InsightMaker model. But now I'm dealing with some pesky un...

okey dokey, live and learn.

OK, now I know what the problem is (is this mentioned in the documentation anywhere, if so, I couldn't find it). I'm using PLE so don't have subscripts, so I'll try to work it out with multiple variables. This is a good (if painful) way to learn these little gotchas in Vensim. Also, a followup quest...

I tried your suggestion as follows: {inputs: a=1, b=2, c=3, d=4} 100 {initial value for result} c = IF THEN ELSE( a > b , 1, 0 ) {false, so c=0} c = IF THEN ELSE( c=0 :AND: d <= 3 , 1 , 0 ) {false, so c=0} c = IF THEN ELSE( c=0 :AND: d > 3 , 10 , 20 ) {true, so c=10} c * d {should = 10 * 5, so resul...

I'm trying to avoid the nesting by using the value q=0 as a kind of flag. The variable I'm assigning here is [g]. If the first IF statement evaluates to TRUE, we assign q=1 so we can skip the next two IF statements (which require q=0). But if pE > w is FALSE, then we need to do more work, so we set ...

Thanks Tom. That makes sense. So you can assign a value to a variable in an equation, but only if you don't include any more code after the assignment? I thought maybe changing [result] and [result2] to Levels instead of Auxiliaries might do the trick. It does fix [result2] (removing the 100 in the ...

Looks like I ran out of attachments. Here is the model.

I notice over 40 views of my original post, but not one reply. I've continued to dig around, and the problem is looking more like a bug than user error to me, but of course I'm ready to stand corrected if this is simply a "you forgot to put a comma here" problem. Here's a really simple mod...

A bit more background on this puzzler. The full equation this code comes from is actually assigning the variable [g] and here it is deciding whether to modify the original value of [g] with one of these values of [q] (of course if q=1, that will leave [g] unchanged). Here's the whole equation: (Io +...

I tried to take your advice and simplify the equations, setting q=0 as a flag to enter what had been nested IFs. The code now looks like this (with comments properly marked): IF THEN ELSE( pE > w , q=1, q=0 ) {if Ecosphere size [pE] is above [w], set q=1} IF THEN ELSE( q=0 :AND: Time <= sy , q=1 , q...

My apologies! I grabbed the wrong commenting character from my memory banks. The comments were just to help me make sure I was at the right level for each IF statement. The revised code, with the comments properly marked (below), still fails with the 'Expecting an operator' error. I certainly unders...

I'm trying to translate some fairly complex InsightMaker code into a Vensim model and have been beating my head against the wall all day with this equation, trying to get rid of 'Expecting an operator' errors. Here's the code: IF THEN ELSE( pE < w , # if true that pE < w IF THEN ELSE( Time-sy <= 0 ,...

Thank you! That fixed it.

the units in the pop-data-lookup-variable.jpg image should be 'people' not 'people/Year'. I forgot to change it back before I captured the image.

I'm trying to reproduce a relatively simple world population model in Vensim. This is my first full model so I'm running into lots of issues, most of which I've been able to figure out, but this one is so simple it has me stumped. This model is somewhat like the rabbit models in the tutorials. I hav...

Thanks for the quick reply Tom. I agree the old format wasn't perfect, but the new one is definitely inferior, IMHO. In my 4 variable graph, in the old format I could see what kind of range I was getting for all 4 variables, in the new format I can only see 2, so that requires extra work to see how ...

I'm new to Vensim, using version 9.3.4 on a 2019 MacBook Pro, MacOS 12.5.1. I got interested in replicating a dynamic system model called HANDY, which models population, inequality, and resource depletion. This model is discussed in a 2013 YouTube video https://www.youtube.com/watch?v=FPeK9JQ9tqg&am...