Search found 2636 matches

by tomfid
Fri Aug 16, 2019 7:29 pm
Forum: Vensim
Topic: vensim .mdl extension applied to flight sim files
Replies: 7
Views: 20

Re: vensim .mdl extension applied to flight sim files

If your flight simulator is still choking on this somehow, my recommendation would be to re-associate the files with the flight simulator. Then you will have the reverse problem, that you won't be able to open a Vensim model via a double-click in Explorer. But you'll still be able to open models fro...
by tomfid
Wed Aug 14, 2019 8:36 pm
Forum: Vensim
Topic: vensim .mdl extension applied to flight sim files
Replies: 7
Views: 20

Re: vensim .mdl extension applied to flight sim files

Vensim does register for the mdl file time when installed, but on Windows the file type really has no effect on a program's access to a file. There's no "renaming" involved. So, I don't see how that could affect your simulator's performance. What was the specific symptom of the crash? Is there an er...
by tomfid
Tue Aug 13, 2019 6:51 pm
Forum: Vensim
Topic: New User (Graduate Engineering Student) Modeling/Software Issues with Real Time Experiment
Replies: 7
Views: 50

Re: New User (Graduate Engineering Student) Modeling/Software Issues with Real Time Experiment

I think there are still several problems here. 1. Units don't balance. This is an automatic disqualifier in my view. 2. I don't think area and strain can be independent. As long as density is constant, the volume of the sample will be conserved, so increasing strain decreases area, without integrati...
by tomfid
Mon Aug 12, 2019 9:21 pm
Forum: Vensim
Topic: Error: Variable not used in the model
Replies: 1
Views: 8

Re: Error: Variable not used in the model

The "not used" issue is a warning, not an error. You can suppress it by checking the "Supplementary" box in the equation editor for the two variables in question.

If the model won't run, something else more serious is wrong.
by tomfid
Mon Aug 12, 2019 1:55 pm
Forum: Vensim
Topic: Change the default legend in the custom graph tool
Replies: 2
Views: 12

Re: Change the default legend in the custom graph tool

1. Can't presently be done, but this tool will get an overhaul in a forthcoming release.
2. You could do this using the "Label" field, but you'd have to have one entry per subscript element shown, which would be a little cumbersome.
by tomfid
Thu Aug 08, 2019 7:52 pm
Forum: Vensim
Topic: New User (Graduate Engineering Student) Modeling/Software Issues with Real Time Experiment
Replies: 7
Views: 50

Re: New User (Graduate Engineering Student) Modeling/Software Issues with Real Time Experiment

I think what you have is correct, but you're violating the SD stock-flow conventions by introducing the stiffness parameter into the stock via an information arrow. If you want to follow conventions, Strain is a stock (as is) with a flow of Elongation, and elongation = force/area/stiffness. I don't ...
by tomfid
Thu Aug 08, 2019 1:30 pm
Forum: Vensim
Topic: New User (Graduate Engineering Student) Modeling/Software Issues with Real Time Experiment
Replies: 7
Views: 50

Re: New User (Graduate Engineering Student) Modeling/Software Issues with Real Time Experiment

I don't think you want to make the area a stock. It's a function of the elongation of the object.
by tomfid
Tue Aug 06, 2019 9:55 pm
Forum: Ventity
Topic: using Visualizer without shapes
Replies: 4
Views: 43

Re: using Visualizer without shapes

I should probably cook up an example. But the basic idea at present would be to assign a location (lat/lon) to each individual in the model, and then color the points according to infection status. Now that I think about it, points don't currently have dynamic size/shape/color, but that should be wo...
by tomfid
Tue Aug 06, 2019 9:52 pm
Forum: Ventity
Topic: using Visualizer without shapes
Replies: 4
Views: 43

Re: using Visualizer without shapes

Right.
by tomfid
Tue Aug 06, 2019 9:14 pm
Forum: Vensim
Topic: Is there an equation for counter in Vensim?
Replies: 2
Views: 45

Re: Is there an equation for counter in Vensim?

If you need a fixed window, you can use something like: avg input = x in window/tau x in window = INTEG( input - outflow, input*tau ) outflow = DELAY FIXED( input, tau, input ) tau = 3 The time scale tau needs to be an integer multiple of the time step for this to initialize correctly, though you co...
by tomfid
Tue Aug 06, 2019 9:11 pm
Forum: Vensim
Topic: Is there an equation for counter in Vensim?
Replies: 2
Views: 45

Re: Is there an equation for counter in Vensim?

An extremely simple implementation would be A = PR/SMOOTH(PR,smoothing time) smoothing time = 3 The SMOOTH function gives you an exponentially-weighted moving average of its input, which is often a good model of perception. A fixed window is typically not as good a model of perception, unless there'...
by tomfid
Tue Aug 06, 2019 9:08 pm
Forum: Ventity
Topic: using Visualizer without shapes
Replies: 4
Views: 43

Re: using Visualizer without shapes

It can be done by specifying "map item" entities, which are points with lat/lon.

We'll be bringing back the 3D visualizer for simpler non-GIS applications like this.
by tomfid
Tue Aug 06, 2019 8:27 pm
Forum: Ventity
Topic: Rabbits by color - help example
Replies: 3
Views: 298

Re: Rabbits by color - help example

At the moment, I don't think so. I'll see if I can think of a workaround.
by tomfid
Tue Aug 06, 2019 8:25 pm
Forum: Ventity
Topic: Interactive and Dynamic Cohorts
Replies: 2
Views: 42

Re: Interactive and Dynamic Cohorts

There are several ways to do this, depending on how large a vector of vehicle types you need. Here are two: VehicleCohorts.zip In #1, each cohort includes separate stocks of EVs and ICEs. This is pretty simple. In #2, the idea of the "fleet" is generalized so that the total market includes separate ...
by tomfid
Tue Aug 06, 2019 6:36 pm
Forum: Ventity
Topic: sensitivity runs
Replies: 1
Views: 19

Re: sensitivity runs

There isn't - but there should be. I'll put in a feature request ticket.
by tomfid
Tue Aug 06, 2019 1:39 pm
Forum: Vensim
Topic: BUG: Graphs not have same scaling b/t mac and win
Replies: 5
Views: 49

Re: BUG: Graphs not have same scaling b/t mac and win

There's that, but there are also some options on the scaling tab of the control panel.
by tomfid
Tue Aug 06, 2019 1:39 am
Forum: Vensim
Topic: BUG: Graphs not have same scaling b/t mac and win
Replies: 5
Views: 49

Re: BUG: Graphs not have same scaling b/t mac and win

That could be a graph settings issues - there are settings for tight and loose scaling and inclusion of 0. Yours might not match theirs.
by tomfid
Mon Aug 05, 2019 10:41 pm
Forum: Vensim
Topic: Input data excel import
Replies: 4
Views: 39

Re: Input data excel import

Actually, you might only need Pro.
by tomfid
Mon Aug 05, 2019 9:51 pm
Forum: Vensim
Topic: BUG: Graph legends include the file extension but shouldn't
Replies: 2
Views: 24

Re: BUG: Graph legends include the file extension but shouldn't

This may be necessary for situations where users have new and old datasets in the same location.

Perhaps the rule for x64 should be that the extension is omitted for the native vdfx, and shown only for the legacy vdf.
by tomfid
Wed Jul 31, 2019 5:20 pm
Forum: Vensim
Topic: Delay function
Replies: 3
Views: 63

Re: Delay function

by tomfid
Tue Jul 30, 2019 5:37 pm
Forum: Ventity
Topic: GIS function
Replies: 8
Views: 168

Re: GIS function

The issue seems to be the projection - MGI/Austria Lambert. I reprojected the file to WGS84 in qgis, and the result works.
by tomfid
Mon Jul 29, 2019 5:48 pm
Forum: Vensim
Topic: How to run sensitivity simulations with Vensim DLL
Replies: 3
Views: 58

Re: How to run sensitivity simulations with Vensim DLL

The most likely candidate is a filename mismatch, or file in wrong directory.

Usually the easiest thing is to prototype your commands as a command script.

RUNNAME controls the run name, same as for ordinary simulations.
by tomfid
Mon Jul 29, 2019 4:34 pm
Forum: Vensim
Topic: Problem with the random uniform generator
Replies: 4
Views: 79

Re: Problem with the random uniform generator

Forgot the attachment:
test3arr.mdl
(10.24 KiB) Downloaded 6 times
by tomfid
Mon Jul 29, 2019 4:33 pm
Forum: Vensim
Topic: Problem with the random uniform generator
Replies: 4
Views: 79

Re: Problem with the random uniform generator

I'm not convinced that there's a problem. I used the attached modified model to run a sample of 1000 realizations at once, and looked at the statistics for the cumulated "input". The expected value of the standard deviation of "input" given by the binomial distribution is sqrt(100000*0.2*(1-0.2))=12...