Search found 3806 matches
- Mon Jun 03, 2013 4:19 pm
- Forum: Vensim
- Topic: Vensim PLE and 64 bit Windows
- Replies: 3
- Views: 2667
Re: Vensim PLE and 64 bit Windows
I rather doubt that the operating system has anything to do with it, because loads of people are running Vensim in 64bit environments.
- Mon Jun 03, 2013 4:18 pm
- Forum: Vensim
- Topic: QUEUE FIFO with items going on hold
- Replies: 7
- Views: 4241
Re: QUEUE FIFO with items going on hold
If I understand correctly, the challenge is that items need to jump in line into the queue, according to their age? I'm guessing that this will have to be done with an explicit stock/flow structure, because the QUEUE functions won't permit it.
- Mon Jun 03, 2013 4:06 pm
- Forum: Vensim
- Topic: QUEUE FIFO with items going on hold
- Replies: 7
- Views: 4241
Re: QUEUE FIFO with items going on hold
Do you really need discrete item age tracking for some kind of tactical planning process, or is this just a part of some larger strategic model, so that some kind of coflow formulation would work? A solution might be possible with QUEUE ... ATTRIBUTE, where the attribute is the creation date of the ...
- Sat Jun 01, 2013 3:01 am
- Forum: Vensim
- Topic: License Vensim DSS
- Replies: 4
- Views: 3175
Re: License Vensim DSS
There are also volume discounts - let us know if you need a quote.
- Fri May 31, 2013 2:49 pm
- Forum: Vensim
- Topic: Fish Stocking Model
- Replies: 7
- Views: 5081
Re: Fish Stocking Model
An example ...
- Fri May 31, 2013 2:23 pm
- Forum: Vensim
- Topic: Fish Stocking Model
- Replies: 7
- Views: 5081
Re: Fish Stocking Model
Another option would be lookup + PULSE TRAIN as the trigger. PULSE TRAIN may be a little simpler to use than IF THEN ELSE( MODULO(Time, ... )), as you don't have to worry about roundoff and time step boundaries.
- Tue May 28, 2013 6:22 pm
- Forum: Vensim
- Topic: time deley
- Replies: 12
- Views: 7827
- Tue May 28, 2013 2:20 pm
- Forum: Vensim
- Topic: time deley
- Replies: 12
- Views: 7827
Re: time deley
You could probably break the simultaneity by using 0*SMOOTHi(input,1,1) instead of just input. The smooth contains an internal level, and initializing it to a constant will break the simultaneity.
- Tue May 28, 2013 4:02 am
- Forum: Vensim
- Topic: SimSetup in VenSim6.1
- Replies: 1
- Views: 1729
Re: SimSetup in VenSim6.1
Sorry Dale - we definitely haven't removed anything. Must be a glitch. We'll sort it out ASAP. - Tom
- Tue May 28, 2013 2:10 am
- Forum: Vensim
- Topic: time deley
- Replies: 12
- Views: 7827
Re: time deley
There are two options - use the :IGNORE: keyword, or just use the variable in the equation, multiplied by zero - for example,
fakeStock = inputA*inputB + 0*ignoredRate
fakeStock = inputA*inputB + 0*ignoredRate
- Mon May 27, 2013 5:57 pm
- Forum: Vensim
- Topic: stop generation of .vdf file
- Replies: 6
- Views: 3292
Re: stop generation of .vdf file
It's probably possible to do some simple MOO using Vensim tools, but there isn't direct support for things like finding the Pareto frontier.
Have you succeeded in hooking the two together yet? Are you using the .dll or DDE?
Tom
Have you succeeded in hooking the two together yet? Are you using the .dll or DDE?
Tom
- Mon May 27, 2013 3:48 pm
- Forum: Vensim
- Topic: time deley
- Replies: 12
- Views: 7827
Re: time deley
You can violate diagramming conventions by using an auxiliary (i.e. instantaneous) variable and showing it with a box on the diagram. Either, - right-click an auxiliary on the diagram, and change its shape to "box" or, - in a level variable, using the equation editor, change the variable t...
- Sun May 26, 2013 1:14 pm
- Forum: Vensim
- Topic: Linear Program
- Replies: 14
- Views: 7428
Re: Linear Program
Great! I didn't think of that.
Let me know if you have specific thoughts about desired functionality.
Let me know if you have specific thoughts about desired functionality.
- Fri May 24, 2013 5:22 pm
- Forum: Vensim
- Topic: [HELP] error with million value
- Replies: 7
- Views: 4697
Re: [HELP] error with million value
There's a workaround for this if you use Double Precision Vensim. In that case, the file format still stores floats, but (optionally) values can be imported from .cin or spreadsheet files as doubles.
- Thu May 23, 2013 1:11 pm
- Forum: Vensim
- Topic: [HELP] error with million value
- Replies: 7
- Views: 4697
Re: [HELP] error with million value
Again, this is normal behavior - scientific notation. In DSS, the display of numbers in tables is controllable (right-click the table tool and select "Pretty" or "Scientific" number format). But large numbers in the model equations are always stored in floating point format. In a...
- Wed May 22, 2013 5:36 pm
- Forum: Vensim
- Topic: How can i replace the optimization algorithm?
- Replies: 27
- Views: 10226
Re: How can i replace the optimization algorithm?
Have you upgraded Vensim in the interim?
What is the symptom of the failure? Does the vensim_command() with the LOADMODEL return 0, or are you unable to load the dll or call the function at all?
What is the symptom of the failure? Does the vensim_command() with the LOADMODEL return 0, or are you unable to load the dll or call the function at all?
- Wed May 22, 2013 12:52 pm
- Forum: Vensim
- Topic: One-to-Many allocation problem
- Replies: 3
- Views: 2079
Re: One-to-Many allocation problem
I think constraining the rate of change of production, rather than an actual scheduled production rate, is adding a level of indirection that I'm not following. If you can post a submodel implementing this, it would be helpful.
- Tue May 21, 2013 10:53 pm
- Forum: Vensim
- Topic: One-to-Many allocation problem
- Replies: 3
- Views: 2079
Re: One-to-Many allocation problem
How about if you just surround AdjFGI with a MAX(0,...) or IF THEN ELSE() that prevents negative values? Have you check the ALLOCATE sample models in the help system? Also see the Allocation section, http://www.vensim.com/documentation/allocation_overview.htm This case can probably be handled by ALL...
- Tue May 21, 2013 3:09 pm
- Forum: Vensim
- Topic: [HELP] error with million value
- Replies: 7
- Views: 4697
Re: [HELP] error with million value
This is scientific notation, http://en.wikipedia.org/wiki/Scientific_notation
2.53e+6 = 2.53 * 10^6 = 2.53 * 1,000,000 = 2,530,000
Excel understands scientific notation, so there's no problem exporting the results for further calculation.
2.53e+6 = 2.53 * 10^6 = 2.53 * 1,000,000 = 2,530,000
Excel understands scientific notation, so there's no problem exporting the results for further calculation.
- Sat May 18, 2013 11:50 pm
- Forum: Vensim
- Topic: How to set optimisation option
- Replies: 2
- Views: 1903
Re: How to set optimisation option
How large is large? You can't expect much from models with multiple optimal and high parameter dimensionality.
- Sat May 18, 2013 11:19 pm
- Forum: Vensim
- Topic: Vensim PLE plus and Excel 2010
- Replies: 19
- Views: 13279
Re: Vensim PLE plus and Excel 2010
Actually they don't need to be shadow variables (unless appearing more than once on a diagram), but often they are used that way. Sounds like a good topic for a quick video clip ...
- Sat May 18, 2013 6:05 pm
- Forum: Vensim
- Topic: Vensim PLE plus and Excel 2010
- Replies: 19
- Views: 13279
Re: Vensim PLE plus and Excel 2010
The syntax of a lookup is just like a function call, e.g. y = f(x), where f() is the lookup. A quick trip through the User Guide chapter linked above may help with this. In your case, you need a Lookup: dwg rate lookup = GET XLS LOOKUPS('ROI.xls','project' ,'E','F4' ) and an Auxiliary that uses the ...
- Fri May 17, 2013 8:34 pm
- Forum: Vensim
- Topic: Vensim PLE plus and Excel 2010
- Replies: 19
- Views: 13279
Re: Vensim PLE plus and Excel 2010
The user guide has a chapter on lookups: http://www.vensim.com/documentation/usr08.htm
- Fri May 17, 2013 4:35 pm
- Forum: Vensim
- Topic: Vensim PLE plus and Excel 2010
- Replies: 19
- Views: 13279
Re: Vensim PLE plus and Excel 2010
This is pointed at the wrong filename, but as soon as I change it to 'roi.xls' it works fine. An easy way to do that is to give it a query name flag, like '?roi', so that it'll ask you to locate the file on first use.
- Fri May 17, 2013 4:03 pm
- Forum: Vensim
- Topic: How can i replace the optimization algorithm?
- Replies: 27
- Views: 10226
Re: How can i replace the optimization algorithm?
For maximum speed in the dll, you should run using the SYNTHESIM commands rather than ordinary simulations. http://www.vensim.com/documentation/25172.htm http://www.vensim.com/documentation/25531.htm http://www.vensim.com/documentation/25532.htm Turn AUTO off and use GO to launch simulations, after ...