Search found 2724 matches

by tomfid
Tue Oct 01, 2019 5:26 pm
Forum: Vensim
Topic: Help - remove lines
Replies: 4
Views: 45

Re: Help - remove lines

Presumably you want to remove all but one. :) Without a legend, it's hard to be sure what this is. You need to do one of the following: - unload datasets using the Control Panel's datasets tab - deactivate subscripts using the Subscript Control - edit the custom graph definition using the Control Pa...
by tomfid
Sat Sep 28, 2019 9:01 pm
Forum: Ventity
Topic: Units (Millions and Billions)
Replies: 8
Views: 165

Re: Units (Millions and Billions)

Got it - thanks! I'll put in a ticket and we'll investigate.
by tomfid
Fri Sep 27, 2019 3:53 pm
Forum: Vensim
Topic: BUG: Vensim Manuals inaccessible in Mac 8.0.3
Replies: 8
Views: 112

Re: BUG: Vensim Manuals inaccessible in Mac 8.0.3

I'll see if we can get a different skin from the Help system vendor.
by tomfid
Thu Sep 26, 2019 1:43 pm
Forum: Ventity
Topic: Units (Millions and Billions)
Replies: 8
Views: 165

Re: Units (Millions and Billions)

Thanks. Two requests:
- can you post a screenshot of the save dialog, showing the Excel filename to be used? (Email to us at info at ventity.biz if easier.)
- the text of the extended error message - this will be on the clipboard after you click OK on the "path is not of legal form" dialog.
by tomfid
Wed Sep 25, 2019 6:36 pm
Forum: Ventity
Topic: Units (Millions and Billions)
Replies: 8
Views: 165

Re: Units (Millions and Billions)

Speculation: the path error has something to do with the location where you're saving the file.
by tomfid
Wed Sep 25, 2019 6:34 pm
Forum: Ventity
Topic: Units (Millions and Billions)
Replies: 8
Views: 165

Re: Units (Millions and Billions)

The M is definitely a bug - I've put in a ticket for it.

How did you generate the "path not of legal form" error? The export command is working for me.
by tomfid
Wed Sep 25, 2019 1:42 pm
Forum: Ventity
Topic: Units (Millions and Billions)
Replies: 8
Views: 165

Re: Units (Millions and Billions)

Where do you need these numbers? (Charts, tables, data grid?)

If you copy-paste or export the values to Excel or csv, you'll get the raw numbers.
by tomfid
Wed Sep 25, 2019 3:54 am
Forum: Vensim
Topic: Help please-Calculating number of reinforcing/balancing loops passing a variable in VENSIM PLE
Replies: 6
Views: 89

Re: Help please-Calculating number of reinforcing/balancing loops passing a variable in VENSIM PLE

Unfortunately knowing the number of loops isn't helpful, because many weak loops could be dominated by one strong loop.

You might try this link instead: https://papers.ssrn.com/sol3/papers.cfm ... id=3114407
by tomfid
Mon Sep 23, 2019 7:58 pm
Forum: Vensim
Topic: Creating hyperlink
Replies: 1
Views: 36

Re: Creating hyperlink

Use the Comment tool:
commentTool.png
commentTool.png (327.24 KiB) Viewed 34 times
by tomfid
Mon Sep 23, 2019 5:00 pm
Forum: Vensim
Topic: Help please-Calculating number of reinforcing/balancing loops passing a variable in VENSIM PLE
Replies: 6
Views: 89

Re: Help please-Calculating number of reinforcing/balancing loops passing a variable in VENSIM PLE

You can use the loops tool to count the total number of loops, but not their polarity.

Can you describe your purpose for doing this?

I think what you may really need is eigenvector analysis: https://pdfs.semanticscholar.org/58b4/c ... 845f28.pdf
by tomfid
Sun Sep 22, 2019 4:25 pm
Forum: Vensim
Topic: Converting flow into lookup
Replies: 1
Views: 48

Re: Converting flow into lookup

I can't view the model remotely, but you probably just need to change the type of the variable to "lookup".

See:
https://vensim.com/lookups-in-vensim/
http://vensim.com/documentation/usr08.htm
by tomfid
Sun Sep 22, 2019 4:20 pm
Forum: Vensim
Topic: Time Setting
Replies: 3
Views: 62

Re: Time Setting

Chapter 18 of the User Guide is a good example of a model calibrated against data:
http://vensim.com/documentation/usr18.htm
by tomfid
Sat Sep 21, 2019 3:02 pm
Forum: Vensim
Topic: Time Setting
Replies: 3
Views: 62

Re: Time Setting

Same file for sure. What you want is a dynamic structure that replicates the data over the historical period, then runs into the future for projections.
by tomfid
Fri Sep 20, 2019 3:33 pm
Forum: Vensim
Topic: Uploading Data onto Vensim PLE
Replies: 27
Views: 5298

Re: Uploading Data onto Vensim PLE

I'm on the road and can't modify the model, plus I don't have the data. But the structure you already have for "fit degression rate" is exactly what you need. "FIT degression rate DATA" is the lookup and "FIT degression rate" is the value looked up from the data, by time.
by tomfid
Fri Sep 20, 2019 3:28 pm
Forum: Vensim
Topic: Help - please
Replies: 2
Views: 51

Re: Help - please

Is this a data variable? If so, the line won't extend past the end of the data.
by tomfid
Tue Sep 17, 2019 9:18 pm
Forum: Vensim
Topic: sensitivity analysis (vensim)
Replies: 27
Views: 865

Re: sensitivity analysis (vensim)

I think the "wrong type" error only occurs if a variable is not a constant (the "not found" is misleading). Most likely causes are setting the constant subtype to unchangeable (with ==), setting the type to initial(), or simply specifying a nonnumeric expression for the variable, like x*y or 3/4.
by tomfid
Tue Sep 17, 2019 6:01 pm
Forum: Vensim
Topic: sensitivity analysis (vensim)
Replies: 27
Views: 865

Re: sensitivity analysis (vensim)

I think the second error is a consequence of the first. It's not finding Yearly Depreciation Factor, and therefore not adding it as an input. Are there other parameters in the vsc?

Does Yearly Depreciation Factor have an array dimension? It's not set to "Initial" type by accident?
by tomfid
Tue Sep 17, 2019 5:03 pm
Forum: Vensim
Topic: sensitivity analysis (vensim)
Replies: 27
Views: 865

Re: sensitivity analysis (vensim)

Sounds like your control file (.vsc) specifies a variable that doesn't exist or isn't constant.
by tomfid
Sun Sep 15, 2019 5:12 pm
Forum: Vensim
Topic: Uploading Data onto Vensim PLE
Replies: 27
Views: 5298

Re: Uploading Data onto Vensim PLE

It would be exactly the same structure as you have for FIT Degression Rate.
by tomfid
Fri Sep 13, 2019 5:56 pm
Forum: Vensim
Topic: Uploading Data onto Vensim PLE
Replies: 27
Views: 5298

Re: Uploading Data onto Vensim PLE

Normally you would specify the data file in the Data Sources... field, on the Advanced tab of the simulation control dialog (Model>Simulate menu).

However, PLE doesn't do data variables, so you'd have to use another lookup.
by tomfid
Tue Sep 10, 2019 12:32 am
Forum: Vensim
Topic: Reference for Vensim's automatic calibration
Replies: 4
Views: 128

Re: Reference for Vensim's automatic calibration

You could cite: Powell, M. J. D. (1964). "An efficient method for finding the minimum of a function of several variables without calculating derivatives". Computer Journal. 7 (2): 155–162. doi:10.1093/comjnl/7.2.155. Press, WH; Teukolsky, SA; Vetterling, WT; Flannery, BP (2007). "Section 10.7. Direc...
by tomfid
Mon Sep 09, 2019 2:48 pm
Forum: Vensim
Topic: Random Number generation
Replies: 1
Views: 58

Re: Random Number generation

The scale parameter determines the mean (assuming shift=0 and there is no truncation), and therefore is the inverse of the lambda parameter typically described for the distribution. The standard deviation equals the mean (variance = mean^2). So, you could use shift=0 and scale=mean of your data. See...