Search found 3804 matches
- Tue Sep 22, 2015 4:10 pm
- Forum: Ventity
- Topic: Possible performance issue with Windows Update
- Replies: 4
- Views: 6749
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: 2780
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: 1474
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: 2757
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: 2757
- Tue Sep 08, 2015 9:44 pm
- Forum: Vensim
- Topic: How to store and retrieve past variable values
- Replies: 2
- Views: 2032
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: 1724
- Tue Sep 08, 2015 5:09 pm
- Forum: Ventity
- Topic: Delay and smooth functions in ventity
- Replies: 1
- Views: 2942
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: 5190
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: 4655
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: 2651
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: 5688
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: 5688
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: 5867
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: 5867
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: 2834
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: 5867
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: 5867
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: 4556
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: 1457
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: 9886
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...
- Fri Aug 07, 2015 5:48 pm
- Forum: Vensim
- Topic: Deleting shadow variables
- Replies: 3
- Views: 2754
Re: Deleting shadow variables
No harm done; seems like a worthy experiment.
- Fri Aug 07, 2015 2:02 pm
- Forum: Vensim
- Topic: Passing a cost at a discrete time to a variable
- Replies: 13
- Views: 6303
Re: Passing a cost at a discrete time to a variable
Hotel construction 2.mdl Here are two general strategies - changes highlighted. Option A is to charge the construction with the flow when it occurs. Option B is to detect changes in the stock, using DELAY FIXED to keep track of the previous value, and charge accordingly. I think A is the preferred ...
- Thu Aug 06, 2015 1:58 pm
- Forum: Vensim
- Topic: Migrating values w/in an array (or to another if necessary!)
- Replies: 9
- Views: 5302
Re: Migrating values w/in an array (or to another if necessa
Yes, I think a little more information about the problem statement would help here.
- Thu Aug 06, 2015 2:30 am
- Forum: Vensim
- Topic: Migrating values w/in an array (or to another if necessary!)
- Replies: 9
- Views: 5302
Re: Migrating values w/in an array (or to another if necessa
Filtering the 0s would be more complicated, but I think it's doable. I can't cook up an answer on the fly though. Here's a stab at the simple way - not sure it's really responsive to your situation, but code is the best way to find out: objects : (o1-o60)~~| objects1 : (o1-o20) -> objects2, objects3...