Search found 3282 matches

by tomfid
Thu Jul 29, 2021 6:04 pm
Forum: Vensim
Topic: I'm having the following problem
Replies: 13
Views: 58

Re: I'm having the following problem

There shouldn't be any difference between single and double precision with respect to syntax. Not knowing what the specific error is, it's hard to say more.
by tomfid
Thu Jul 29, 2021 5:13 pm
Forum: Vensim
Topic: I'm having the following problem
Replies: 13
Views: 58

Re: I'm having the following problem

If you're getting a syntax error in double precision, after successfully opening it earlier, the file is probably corrupted somehow. The version you posted here works fine for me, especially after the ELMCOUNT change.
by tomfid
Thu Jul 29, 2021 5:12 pm
Forum: Vensim
Topic: I'm having the following problem
Replies: 13
Views: 58

Re: I'm having the following problem

You have "size n" = 1. It should be set to the ELMCOUNT(commod) normally.
by tomfid
Thu Jul 29, 2021 12:14 pm
Forum: Vensim
Topic: I'm having the following problem
Replies: 13
Views: 58

Re: I'm having the following problem

I don't get an error. What version are you using?
by tomfid
Fri Jul 23, 2021 6:13 pm
Forum: Vensim
Topic: Comment text formatting options.
Replies: 6
Views: 103

Re: Comment text formatting options.

Thanks - that's helpful.

I think what we really want is some kind of rich text container that avoids the one-line-field constraint. We'll take a look at what's possible. Should be quicker to implement with the new graphics.
by tomfid
Fri Jul 23, 2021 2:40 pm
Forum: Vensim
Topic: If then Else
Replies: 3
Views: 39

Re: If then Else

On other thought: Groundwater allocation volume for consumptive use/Time will produce a declining allocation as simulation time increases. This would be especially problematic if INITIAL TIME = 0. Maybe a parameter describing the minimum time required to consume the remaining volume would be more ap...
by tomfid
Thu Jul 22, 2021 2:23 pm
Forum: Vensim
Topic: Changes for command scripts for Vensim 8+?
Replies: 3
Views: 52

Re: Changes for command scripts for Vensim 8+?

In the current v9 beta, this can be run (but fails because I don't have the source xls files). There's no indication of a syntax problem. I get the same result in 8.2.1 x64 and x32. I think we need the xls for further testing - you can email if sensitive.
by tomfid
Thu Jul 22, 2021 2:14 pm
Forum: Vensim
Topic: Changes for command scripts for Vensim 8+?
Replies: 3
Views: 52

Re: Changes for command scripts for Vensim 8+?

There haven't been any changes (other than a few additions that wouldn't affect this). Syntax checking might have become more picky somewhere.
by tomfid
Wed Jul 14, 2021 2:17 pm
Forum: Vensim
Topic: "Formatting..." message in View As Text mode
Replies: 4
Views: 116

Re: "Formatting..." message in View As Text mode

vensim at vensim.com.
by tomfid
Wed Jul 14, 2021 1:07 pm
Forum: Vensim
Topic: newbe and wine64
Replies: 4
Views: 102

Re: newbe and wine64

Using PySD might be a good option. It's pretty simple, but it can translate Vensim mdl files.
by tomfid
Tue Jul 13, 2021 7:47 pm
Forum: Vensim
Topic: "Formatting..." message in View As Text mode
Replies: 4
Views: 116

Re: "Formatting..." message in View As Text mode

A fallback option is to use an external editor like Notepad++ on the .mdl file, but you shouldn't normally need that.
by tomfid
Tue Jul 13, 2021 2:09 pm
Forum: Vensim
Topic: newbe and wine64
Replies: 4
Views: 102

Re: newbe and wine64

You can create a DSN in Windows with the Microsoft admin tools, https://support.microsoft.com/en-us/office/administer-odbc-data-sources-b19f856b-5b9b-48c9-8b93-07484bfab5a7#bm2 However, I don't know how this would work with Wine. I don't think Linux is an interesting market for Vensim, because its d...
by tomfid
Fri Jul 02, 2021 7:34 pm
Forum: Vensim
Topic: Error: Simulate button that does not work and MS3321 error
Replies: 16
Views: 352

Re: Error: Simulate button that does not work and MS3321 error

Great. These weird OS interactions can be frustrating. Glad it's working.
by tomfid
Thu Jul 01, 2021 8:39 pm
Forum: Vensim
Topic: Optimization Constraints using non-constants, percentages summing to 1.0
Replies: 9
Views: 181

Re: Optimization Constraints using non-constants, percentages summing to 1.0

Reality Check and optimization don't interact at all. Reality Checks could tell you there was a problem with the allocation, but not correct the problem. Optimization may not be good for the user experience because it takes time and doesn't work with synthesim (though that may change in the future)....
by tomfid
Thu Jul 01, 2021 6:33 pm
Forum: Vensim
Topic: Error: Simulate button that does not work and MS3321 error
Replies: 16
Views: 352

Re: Error: Simulate button that does not work and MS3321 error

Is there anything in the error log? This should be in %appdata%\Roaming\Vensim\vensimdp.err.

I would be tempted to manually delete or rename %appdata%\Roaming\Vensim and c:\program files\Vensim (or C:\Program Files (x86)\Vensim if 32 bit) and do a clean reinstall.
by tomfid
Thu Jul 01, 2021 6:09 pm
Forum: Vensim
Topic: Optimization Constraints using non-constants, percentages summing to 1.0
Replies: 9
Views: 181

Re: Optimization Constraints using non-constants, percentages summing to 1.0

This sounds somewhat like a Bayesian estimation problem, where you want to find a parameter value that best fits the data, subject to some prior belief about the plausible range of values. In this case, user input could be taken as a suggestion, and the optimizer could be turned loose to maximize so...
by tomfid
Thu Jul 01, 2021 3:05 pm
Forum: Vensim
Topic: Optimization Constraints using non-constants, percentages summing to 1.0
Replies: 9
Views: 181

Re: Optimization Constraints using non-constants, percentages summing to 1.0

There is another way to do it, which is to create an additional term in the payoff that penalizes deviation from sum=100%. However that's usually less efficient.
by tomfid
Thu Jul 01, 2021 3:04 pm
Forum: Vensim
Topic: Optimization Constraints using non-constants, percentages summing to 1.0
Replies: 9
Views: 181

Re: Optimization Constraints using non-constants, percentages summing to 1.0

You need to put these in the model as new equations.
by tomfid
Fri Jun 25, 2021 8:33 pm
Forum: Vensim
Topic: Can I use LOOKUP SLOPE to access point to point slopes as rate data?
Replies: 3
Views: 125

Re: Can I use LOOKUP SLOPE to access point to point slopes as rate data?

I think the key difference here is that time step = .015625.
by tomfid
Fri Jun 25, 2021 7:48 pm
Forum: Vensim
Topic: Can I use LOOKUP SLOPE to access point to point slopes as rate data?
Replies: 3
Views: 125

Re: Can I use LOOKUP SLOPE to access point to point slopes as rate data?

I think the reason you're not seeing what you expect is that your model time step is 1, so you aren't evaluating any points that are in between the data points.

Make time step << 1 and you'll see something like the gray line.
by tomfid
Wed Jun 23, 2021 3:19 pm
Forum: Vensim
Topic: Optimization: data import format
Replies: 5
Views: 202

Re: Optimization: data import format

Nice notes! The general insight here is that imported data (from .dat, .tab, .csv, etc.) requires variable names that match model names, at least if you want to be able to plot the model variable and the data variable on the same graph. Your original import created a valid dataset (mydata.vdfx or wh...
by tomfid
Tue Jun 22, 2021 9:33 pm
Forum: Vensim
Topic: Optimization: data import format
Replies: 5
Views: 202

Re: Optimization: data import format

Oh, wait ... if your data looks like this: B reaction curve 1 9.516258196 2 18.12692469 3 25.91817793 4 32.9679954 5 39.34693403 ... your data variable will be "B reaction curve" which won't plot when your workbench variable is A or B. If you want to plot against simulated B, use B 1 9.516258196 2 1...
by tomfid
Tue Jun 22, 2021 9:21 pm
Forum: Vensim
Topic: Optimization: data import format
Replies: 5
Views: 202

Re: Optimization: data import format

What you've done seems right. My first guess would be that you're using a version that had a bug - are you on the latest?

I'll attempt to replicate.
by tomfid
Wed Jun 09, 2021 3:52 pm
Forum: Vensim
Topic: model calibration
Replies: 4
Views: 1553

Re: model calibration

It's on the list for the graphs in the new interface.
by tomfid
Mon Jun 07, 2021 2:42 pm
Forum: Vensim
Topic: Lookup for time series
Replies: 3
Views: 218

Re: Lookup for time series

1. The Help system has a lot of material on lookups. https://vensim.com/documentation/usr08.html
2. Quick start video: https://vimeo.com/55318481