Search found 3811 matches
- Mon Aug 18, 2014 7:34 pm
- Forum: Vensim
- Topic: Problems with "Find zero" convergence
- Replies: 13
- Views: 6175
Re: Problems with "Find zero" convergence
Have you scaled your input vectors to order of magnitude 1? There may be numerical precision issues if not.
- Fri Aug 15, 2014 4:33 pm
- Forum: Vensim
- Topic: Using correlation values obtained from SPSS on Vensim
- Replies: 10
- Views: 5335
Re: Using correlation values obtained from SPSS on Vensim
If the output is constant, then it seems that your inputs must be constant as well (unless the table function relationships are flat). So, the question is, which of your inputs should be varying, and why? You can implement variation in the inputs with test inputs like STEP, PULSE, or SIN, or a looku...
- Fri Aug 15, 2014 2:14 pm
- Forum: Vensim
- Topic: Using correlation values obtained from SPSS on Vensim
- Replies: 10
- Views: 5335
Re: Using correlation values obtained from SPSS on Vensim
Also see
http://dspace.mit.edu/handle/1721.1/11105
Is the oscillation you want a test input in schedule pressure, or desired behavior of quality?
http://dspace.mit.edu/handle/1721.1/11105
Is the oscillation you want a test input in schedule pressure, or desired behavior of quality?
- Fri Aug 15, 2014 2:04 pm
- Forum: Vensim
- Topic: Using correlation values obtained from SPSS on Vensim
- Replies: 10
- Views: 5335
Re: Using correlation values obtained from SPSS on Vensim
Presumably you estimated something like quality = a + b*schedule pressure + err. You can implement that directly in an equation, by importing the a,b coefficients from your estimation. However, it's not likely to be robust, in that quality might take on impossible values for some values of schedule ...
- Fri Aug 15, 2014 1:55 pm
- Forum: Vensim
- Topic: Problem in Stock and Flow for hiring workforce
- Replies: 12
- Views: 5875
Re: Problem in Stock and Flow for hiring workforce
TIME STEP determines how finely time is sliced when the model is integrated. You might get some insight from this ... http://www.vensim.com/documentation/eul ... ime%2Bstep
- Thu Aug 14, 2014 11:15 pm
- Forum: Vensim
- Topic: Vensim debugging
- Replies: 22
- Views: 11955
Re: Vensim debugging
One further thought: unit checking and syntax checking don't really interact, so the correction of the 40 errors from splitting the dimensioned and dimensionless items must be related to the subscripting implications of doing that rather than the units themselves. Any further insight into the detail...
- Thu Aug 14, 2014 6:57 pm
- Forum: Vensim
- Topic: Vensim debugging
- Replies: 22
- Views: 11955
Re: Vensim debugging
Understood.
External functions don't pass units through, but you can normalize all the inputs to dimensionless quantities (perhaps by dividing with a dummy variable, like furlongs per fortnight == 1 ~ furlong/fortnight ).
External functions don't pass units through, but you can normalize all the inputs to dimensionless quantities (perhaps by dividing with a dummy variable, like furlongs per fortnight == 1 ~ furlong/fortnight ).
- Wed Aug 13, 2014 4:41 pm
- Forum: Vensim
- Topic: unhide entire model
- Replies: 2
- Views: 2072
Re: unhide entire model
You'll have to visit each view, but it's fairly quick to do the following:
- hit the 'h' key as needed, so you can see everything
- <control>A to select all
- Edit>Hide to Depth>Unhide
- hit the 'h' key as needed, so you can see everything
- <control>A to select all
- Edit>Hide to Depth>Unhide
- Wed Aug 13, 2014 12:30 am
- Forum: Vensim
- Topic: where is the file containing the warnings message?
- Replies: 4
- Views: 2883
Re: where is the file containing the warnings message?
I've put this on the list of things to look at for 6.4.
- Tue Aug 12, 2014 11:19 pm
- Forum: Vensim
- Topic: Matrix Operation on a User Defined Function
- Replies: 3
- Views: 2233
Re: Matrix Operation on a User Defined Function
Ahh ... that's a different matter. It should indeed work. I assume you have your Tools>Options>Startup>External Function Library path pointed at the right .dll. The /comp folder should include a precompiled venext.dll - you might try pointing at that to see what happens. Have you installed any later...
- Tue Aug 12, 2014 8:08 pm
- Forum: Vensim
- Topic: Matrix Operation on a User Defined Function
- Replies: 3
- Views: 2233
Re: Matrix Operation on a User Defined Function
Did you remember to add the functions to the definition list in section 3 of venext.c? /**************************************************** 3 - Grouping of functions in a structure - see venext.h ***********************************************************/ static FUNC_DESC Flist[] = { {"COSINE...
- Tue Aug 12, 2014 2:07 pm
- Forum: Vensim
- Topic: Vensim debugging
- Replies: 22
- Views: 11955
Re: Vensim debugging
Yikes! Can you post the model, or email it to us so we can take a look?
- Mon Aug 11, 2014 11:35 pm
- Forum: Vensim
- Topic: Vensim debugging
- Replies: 22
- Views: 11955
Re: Vensim debugging
I think your diagnosis may be correct - the error message is incorrect. If I paste your code into the text editor in an empty model, I get the same "on the right not the left" error. The actual problem, though, is that SBHB4 and STHBX1 are undefined. If I add them as data variables, the er...
- Mon Aug 11, 2014 11:22 pm
- Forum: Vensim
- Topic: Vensim debugging
- Replies: 22
- Views: 11955
Re: Vensim debugging
OK - I can replicate the message.
Incidentally, as a shortcut, you can rewrite subscripts like this hierarchically, like:
Incidentally, as a shortcut, you can rewrite subscripts like this hierarchically, like:
Code: Select all
TTRU : ATYP,NMRU~~|
ATYP : ATP1,ATP2,ATP3,ATP4,ATP5~~|
NMRU : ATP6,ATP7,ATP8,ATP9,AT10,AT11~~|
SPRT : SPAR,SPNC~~|
SPAR : SPR1,SPR2,SPR3~~|
SPNC : SPR4,SPR5,SPR6,SPR7~~|
- Mon Aug 11, 2014 4:12 pm
- Forum: Vensim
- Topic: Vensim debugging
- Replies: 22
- Views: 11955
Re: Vensim debugging
Can you supply an example of one of the equations that generates such a message? In a normal model (no external functions), subscripting errors will generally be proximate to the warning messages - i.e., the message either takes you to the erroneous equation, or one of the inputs on the right side i...
- Mon Aug 11, 2014 4:07 pm
- Forum: Vensim
- Topic: where is the file containing the warnings message?
- Replies: 4
- Views: 2883
Re: where is the file containing the warnings message?
If you could do the automation with a sensitivity control file, there's a "Display warning messages" option that would write all the runtime errors to the screen log. Some optimization options write a log file containing errors, but not always - I'll have to look at the code to see what th...
- Mon Aug 11, 2014 3:49 pm
- Forum: Vensim
- Topic: Sensitivity simulation and parameter correlation
- Replies: 5
- Views: 3725
Re: Sensitivity simulation and parameter correlation
Hi JJ - The time series output for variables in the .lst is stored in the .vdf for the simulation run. You can get at it with the sensitivity graph, bar graph histogram, or stats tool options. For other analysis, you can extract the raw output by exporting the dataset (Model>Export Dataset...). - Tom
- Fri Aug 08, 2014 7:46 pm
- Forum: Vensim
- Topic: Sensitivity simulation and parameter correlation
- Replies: 5
- Views: 3725
Re: Sensitivity simulation and parameter correlation
There are two options: Build a structure in the model that generates the correlation (there's a bivariate normal example in http://www.vensim.com/documentation/Models/OptSensi /MCMC). Generate a sample using some other tool and use the File sensitivity option. http://www.vensim.com/documentation/sen...
- Fri Aug 08, 2014 7:31 pm
- Forum: Vensim
- Topic: Time series problem
- Replies: 12
- Views: 5077
Re: Time series problem
There are many options in DSS. You can use the "Import Vals" button in a lookup, though generally data variables are preferred unless you need specific lookup functionality. You can use GET XLS DATA or similar: http://www.vensim.com/documentation/fn_get_xls_data.htm or import from a file -...
- Thu Aug 07, 2014 1:51 am
- Forum: Vensim
- Topic: Time series problem
- Replies: 12
- Views: 5077
Re: Time series problem
PLE isn't really designed for much data work - for that you need a more advanced version. If you want to import the data to a vdf (e.g., for comparison with model output) you need to use the .dat format: http://www.vensim.com/documentation/23460.htm Your Excel workbook is close to that - you'd just ...
- Fri Aug 01, 2014 2:13 pm
- Forum: Vensim
- Topic: Randomized pulse train
- Replies: 15
- Views: 8449
Re: Randomized pulse train
That helps. I'll see if I can create something.
What you really need to simplify the accounting is the SAMPLE IF TRUE function in Vensim Pro or DSS.
What you really need to simplify the accounting is the SAMPLE IF TRUE function in Vensim Pro or DSS.
- Thu Jul 31, 2014 8:49 pm
- Forum: Vensim
- Topic: Randomized pulse train
- Replies: 15
- Views: 8449
Re: Randomized pulse train
I'm finding it quite messy to create a structure that meets this spec, using only the functions in PLE. I can't think of real physical process that has precisely this behavior. What are we actually modeling here?
- Thu Jul 31, 2014 2:31 am
- Forum: Vensim
- Topic: Randomized pulse train
- Replies: 15
- Views: 8449
Re: Randomized pulse train
Are you looking for pulses of controllable width and height, at random times? That can be implemented with a stock structure - I could cook up a demo structure if that's what you're after.
- Fri Jul 25, 2014 1:34 pm
- Forum: Vensim
- Topic: VENSIM DLL
- Replies: 3
- Views: 2475
Re: VENSIM DLL
Vensim DSS is commercial software and requires a license. We're fans of open source ourselves, but the reality is that DSS is a very complex piece of software that wouldn't thrive as open source. Without a revenue stream to support it, there wouldn't be a Vensim, and we couldn't support free PLE eit...
- Tue Jul 22, 2014 8:13 am
- Forum: Vensim
- Topic: Using time as an independant variable
- Replies: 5
- Views: 2725
Re: Using time as an independant variable
Note that in DSS/Pro you wouldn't have to do this manually, because you can automatically add causes to the diagram, and even add variables to the model, from within the equation editor.