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Ugh. The general framework will be something like: QFP1 = IF THEN ELSE( tfp>0 , IF THEN ELSE( expression beginning with pp>0 ,expression beginning with sum over QH ,expression beginning with sum over QH*fraction with pp in numerator ) , 0 ) It's pretty confusing subscripting though - I would strongl...

It's not really a comprehensive project model, but it does show how to set up the subscripting. Unless you do some really arcane stuff, you won't really be doing CPM in Vensim (or any other SD tool). But that's kind of the point: CPM ignores the cross-stage rework cycle, partial concurrency, and oth...

There's a subscripted project model in the User Guide:
https://www.vensim.com/documentation/21195.html

This must predate Apple reversing its approach to big/little endian byte order. I was able to open it in 6.4, but it runs with an error. In the meantime, my similar replication is here: https://metasd.com/2010/03/behavioral-analysis-of-learning-curve-strategy/ This copy is from an earlier version of...

The fee part is a good argument for Forio. They have the architecture for paid use of models; creating that yourself is probably a substantial bit of work.

I can replicate this - it's a bug.

The section you want is in the docs, https://www.vensim.com/documentation/25945.html, but I see it's out of date. Generally what you need (assuming Windows) is: Edit C:\Users\Public\Vensim\vengine\comp\MDLDP64.BAT (this is the compilation script) Early on, you'll see a series of blocks that set up t...

Yes! I usually do something like the following: var = GeometricMean * EXP( GeometricSD*RANDOM NORMAL(-6,6,0,1,0) ) The GeometricMean has the same units as your target variable. The GeometricSD is the standard deviation as a fraction of the mean, i.e. the standard deviation of LN(var/GeometricMean) a...

I think your instincts were good here. Leaving the data in .vdf format should normally work. It's possible that there was a leak in 6.3 that allowed the NAN values to get into the vdf in the first place. For doing a round-trip vdf/vdfx conversion, .dat format is often the easiest, because it doesn't...

If you want to check for :NA: in a data variable, you need to use the :RAW: interpolation method. :INTERPOLATE: only returns :NA: if the series has no data at all.

Another option is to copy-paste the file:

https://superuser.com/questions/206060/ ... out-quotes

When I save this as tab-delimited text, Excel quotes the column headers like "fracDWI[Male,Age15]" This is a nonstandard behavior, because quotes are not needed when the delimiter is tab (only csv). Unfortunately this is not legitimate quoting in Vensim (the subscript brackets should not b...

Thanks Tom I also did not notice the mile per trip is constant, but still interesting how can this happen if there is a link between two variables. It should automatically make constant become AUX. I'm not sure we should do this, because the extra arrow could be a mistake. In the language, constant...

Here are some options.
I think one unit error might have been a typo in "dmnl".

Antivirus?

What error are you seeing?

I'm guessing that you're putting varname[range] in the headers. I don't think that works - you need to provide a separate column for each varname[element].

Just walked through with the debugger.

The first try fails due to loading sequence and issues the error message too soon. The automatic retry works. The bug is that the error message is wrong -- there is not a real problem.

We can get you a nightly build when the fix is included.

Actually, the problem with "miles per trip" is that the equation is constant, but the diagram includes a link from "attractiveness of driving" so the equation is invalid (inconsistent with diagram). We should probably upgrade the warnings to distinguish missing equations from mis...

The others are either correct warnings, or Vensim cannot check as there is no equation to check against. Not so. "miles per trip" is a constant =20 and has unit mile/trip, but it's still reported as an error (no units). I suspect that the parsed model is so incomplete that Vensim fails to...

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

"Don't hold your breath" might still be good advice.

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

"Don't hold your breath" might still be good advice.

The HG B/D mixup looks like a bug to me. Checking with the devs.

However, it's not clear to me that compound keys are needed here, at least for S1. Every S1 Factory is unique, so the group isn't needed to find the factory.

I'll take a look.

Sounds like what you want is a logistic growth model. The model here https://vensim.com/vensim-video-library/#Introduction_to_System_Dynamics_With_Vensim has a variant of that near the 1hr mark, particularly if you make the product lifetime very long so that there's effectively no outflow from custo...

Ventity licensing will be changing to look more like Vensim. In the meantime, we'll include a license with a Pub Rsch Vensim Pro license (email us at info at ventity.biz if it doesn't happen automatically).