Search found 3808 matches
- Wed Sep 23, 2015 5:09 pm
- Forum: Ventity
- Topic: help to understand how Ventity works
- Replies: 5
- Views: 5229
Re: help to understand how Ventity works
I'm working on this. In a sense, there isn't an "aging" mechanism in a Ventity cohort model. You don't have to move people from one cohort to another. You keep track of a list of cohorts, add new cohorts, and delete old ones if they're (nearly) empty. Anything that's inside a single entity...
- Wed Sep 23, 2015 4:01 pm
- Forum: Ventity
- Topic: Problem with deleting an arrow or a note
- Replies: 4
- Views: 4401
Re: Problem with deleting an arrow or a note
Select the item, then hit the <Delete> key.
- Tue Sep 22, 2015 7:08 pm
- Forum: Ventity
- Topic: Build 573 available
- Replies: 0
- Views: 5303
Build 573 available
I'm happy to announce that we've just uploaded a new Ventity beta (build 573). Some of the bigger changes are documented in the Release Notes (see "What's New" in the Help system), but there are also many small usability improvements, particularly to things like diagramming and predictive ...
- Tue Sep 22, 2015 4:22 pm
- Forum: Vensim
- Topic: Vensim Naming Conventions
- Replies: 3
- Views: 2364
Re: Vensim Naming Conventions
I don't use capitalization for anything other than appearance. Adding a lot of tags clutters things and makes the model look geeky to non-technical viewers. I prefer to let the words do the work: stock: noun (people in house, capital) flow: gerund or explicit "rate" (exit rate, investing) ...
- Tue Sep 22, 2015 4:10 pm
- Forum: Ventity
- Topic: Possible performance issue with Windows Update
- Replies: 4
- Views: 7185
Re: Possible performance issue with Windows Update
Win10 does seem to be an improvement all around. I haven't had any issues. The Win8 update issue seems to be resolved as well.
- Wed Sep 16, 2015 2:36 pm
- Forum: Ventity
- Topic: problem in the exercise 6 of the tutorial
- Replies: 1
- Views: 2801
Re: problem in the exercise 6 of the tutorial
Thanks ... I'll check it out.
- Tue Sep 15, 2015 5:11 pm
- Forum: Vensim
- Topic: traffic modelling (roundabout) distribution
- Replies: 1
- Views: 1479
Re: traffic modelling (roundabout) distribution
It might be easiest to generate arrivals for each origin-destination pair independently. See attached for an example.
- Wed Sep 09, 2015 4:54 am
- Forum: Vensim
- Topic: Question on GET XLS DATA
- Replies: 4
- Views: 2763
Re: Question on GET XLS DATA
The data variable won't contain any interpolated or held points, but when it's used, you'll see them downstream.
For example, try:
myData := GET XLS DATA( ... )
myAux = myData
Then play around with the interpolation pattern and take a look at myAux.
For example, try:
myData := GET XLS DATA( ... )
myAux = myData
Then play around with the interpolation pattern and take a look at myAux.
- Tue Sep 08, 2015 9:46 pm
- Forum: Vensim
- Topic: Question on GET XLS DATA
- Replies: 4
- Views: 2763
- Tue Sep 08, 2015 9:44 pm
- Forum: Vensim
- Topic: How to store and retrieve past variable values
- Replies: 2
- Views: 2035
Re: How to store and retrieve past variable values
You can use the DELAY FIXED function to create a stock representing the 3-year moving accumulation. For example:
profit = ...
cumulative profit = INTEG( adding - removing, 0 )
adding = profit
removing = DELAY FIXED( profit, horizon, 0 )
horizon = 3
average profit = cumulative profit / horizon
profit = ...
cumulative profit = INTEG( adding - removing, 0 )
adding = profit
removing = DELAY FIXED( profit, horizon, 0 )
horizon = 3
average profit = cumulative profit / horizon
- Tue Sep 08, 2015 5:11 pm
- Forum: Vensim
- Topic: How to print the maximum value of a stock?
- Replies: 2
- Views: 1728
- Tue Sep 08, 2015 5:09 pm
- Forum: Ventity
- Topic: Delay and smooth functions in ventity
- Replies: 1
- Views: 2961
Re: Delay and smooth functions in ventity
We haven't implemented any of the dynamic functions yet - we're waiting on a bit of development for an internal capability something like Vensim MACRO functions. Some of the complex delays, like conveyors, probably won't be implemented, because they can be done better by creating cohorts of entities...
- Tue Sep 08, 2015 5:07 pm
- Forum: Ventity
- Topic: help to understand how Ventity works
- Replies: 5
- Views: 5229
Re: help to understand how Ventity works
Good idea. We'll see what we can cook up. It may be tricky in some situations, because there are things Ventity does that will be hard to represent in Vensim.
- Tue Sep 01, 2015 6:43 pm
- Forum: Vensim
- Topic: "Nobody ever gets credit" model
- Replies: 5
- Views: 4796
Re: "Nobody ever gets credit" model
It seems like the paper doesn't fully document the models and experiments, so it's hard to know what's missing.
Fixing units is a good start, but I'd email the authors and see if the model, or at least an equation listing, is available.
Fixing units is a good start, but I'd email the authors and see if the model, or at least an equation listing, is available.
- Fri Aug 28, 2015 4:01 pm
- Forum: Vensim
- Topic: Looking for someone with Forio experience
- Replies: 1
- Views: 2855
Re: Looking for someone with Forio experience
I can ask around. You might also try asking on the SD discussion forum.
- Mon Aug 24, 2015 5:42 pm
- Forum: Vensim
- Topic: Improving iterations!
- Replies: 9
- Views: 5705
Re: Improving iterations!
It would help to have a description of what you're trying to achieve with this calculation. There might be an easier way.
- Mon Aug 24, 2015 5:40 pm
- Forum: Vensim
- Topic: Improving iterations!
- Replies: 9
- Views: 5705
Re: Improving iterations!
To use find zero, you'd have to define a one-dimensional array i_j of size ELMCOUNT(i)*ELMCOUNT(j) and map t[i,j] to t2[i_j]. Then you could use the find zero functionality to iterate.
This would probably work better as an external function though.
This would probably work better as an external function though.
- Mon Aug 24, 2015 3:21 pm
- Forum: Vensim
- Topic: How can I fix this problem ?
- Replies: 12
- Views: 5875
Re: How can I fix this problem ?
Here's a double precision .vdf:
- Fri Aug 21, 2015 2:37 pm
- Forum: Vensim
- Topic: How can I fix this problem ?
- Replies: 12
- Views: 5875
Re: How can I fix this problem ?
The only simple, general answer is to switch to a double precision Vensim version. You would have exactly the same problem if you were working in a programming language using floats instead of doubles. But why does this matter in practice? It would be very unusual for a real system to be free of dis...
- Thu Aug 20, 2015 4:26 pm
- Forum: Vensim
- Topic: VECTOR LOOKUP with variable X intervals
- Replies: 4
- Views: 2838
Re: VECTOR LOOKUP with variable X intervals
It's possible with subscripting. Take a look at this:
I did this once before, long ago, and the result was more elegant as I recall, so perhaps someone can improve on it.- Thu Aug 20, 2015 4:23 pm
- Forum: Vensim
- Topic: How can I fix this problem ?
- Replies: 12
- Views: 5875
Re: How can I fix this problem ?
I don't think there's a way to make the exact technical problem go away in general; I'd have to know something about the specific problem to suggest a practical solution.
- Thu Aug 20, 2015 3:22 pm
- Forum: Vensim
- Topic: How can I fix this problem ?
- Replies: 12
- Views: 5875
Re: How can I fix this problem ?
This is a limitation of single-precision number representation. In Vensim DSS double precision, the model comes exactly into equilibrium.
- Thu Aug 13, 2015 4:24 pm
- Forum: Ventity
- Topic: Introducing Ventity beta 1
- Replies: 2
- Views: 4692
Re: Introducing Ventity beta 1
There isn't any document, or interoperability, yet. We will create a translator for Vensim models to Ventity, most likely via XMILE. Simple models and components should translate ~100%. We don't expect full two-way translation of models to be practical. Coming from Vensim, it doesn't make sense to m...
- Mon Aug 10, 2015 4:28 pm
- Forum: Vensim
- Topic: Can´t install the software!
- Replies: 1
- Views: 1462
Re: Can´t install the software!
I just downloaded, installed and ran PLE 5.11 on a Win8.1 x64 machine, and it worked fine. Perhaps your downloaded file really is corrupted. Try the download again?
- Sat Aug 08, 2015 4:35 pm
- Forum: System Dynamics Discussion
- Topic: arcane arrays
- Replies: 9
- Views: 10279
Re: arcane arrays
"Arcane" may not be the best word. However, in my experience, there are often a few points in a model, usually where the dimensionality is changing, that do require very complex and opaque subscripting. Now that I've been using Ventity for a little while, I'm also finding it annoying to ha...