Search found 3808 matches
- Fri Aug 07, 2015 5:48 pm
- Forum: Vensim
- Topic: Deleting shadow variables
- Replies: 3
- Views: 2766
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: 6330
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: 5320
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: 5320
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...
- Thu Aug 06, 2015 12:49 am
- Forum: Vensim
- Topic: Migrating values w/in an array (or to another if necessary!)
- Replies: 9
- Views: 5320
Re: Migrating values w/in an array (or to another if necessa
OK, I think I get it. It seems like an inevitable consequence is that if any subarea has >20 objects, you have a problem fitting them all in with the offsets? With that restriction, I think there's a simple solution. Do you need to pack the vector to get rid of 0s, i.e. 3,17,21,0,19 -> 3,17,21,19 ?
- Wed Aug 05, 2015 10:01 pm
- Forum: Vensim
- Topic: Migrating values w/in an array (or to another if necessary!)
- Replies: 9
- Views: 5320
Re: Migrating values w/in an array (or to another if necessa
Also ... not sure I follow the problem statement. If each of 3 subareas contains up to 60 objects, wouldn't you need a vector of up to 180 elements to store the consolidated positions?
- Wed Aug 05, 2015 9:58 pm
- Forum: Vensim
- Topic: Migrating values w/in an array (or to another if necessary!)
- Replies: 9
- Views: 5320
Re: Migrating values w/in an array (or to another if necessa
How many objects and areas will there be eventually? It might be easier to just use brute force and track every object/area location, rather than trying to reuse IDs.
- Wed Aug 05, 2015 9:55 pm
- Forum: Vensim
- Topic: Deleting shadow variables
- Replies: 3
- Views: 2766
Re: Deleting shadow variables
That's odd ... Delete -> Remove from this view but do not change model structure is what you should be using. I do it all the time. Can you post/send a model saved before/after such an operation? What OS are you on?
- Wed Aug 05, 2015 3:51 pm
- Forum: Ventity
- Topic: Updated build 457
- Replies: 2
- Views: 3259
Re: Updated build 457
Great. I'm sure we'll have more teething problems, but it's good to have the basics working!
- Wed Aug 05, 2015 3:50 pm
- Forum: Vensim
- Topic: floating point issues and warnings
- Replies: 2
- Views: 1738
Re: floating point issues and warnings
I think the problem is that your adoption from advertising is too high. You have: adoption from advertising 0 = "effectiveness of advertising & promotion"*potential users 0*marketing investment So "effectiveness of advertising & promotion"*marketing investment is effectiv...
- Tue Aug 04, 2015 8:28 pm
- Forum: Ventity
- Topic: Updated build 457
- Replies: 2
- Views: 3259
Updated build 457
There's a new build 457 that fixes the help system issues, plus some bug fixes and feature upgrades. Get it at http://vensim.com/ventity.html
- Tue Aug 04, 2015 8:24 pm
- Forum: Ventity
- Topic: Possible performance issue with Windows Update
- Replies: 4
- Views: 7190
Re: Possible performance issue with Windows Update
We found it on Windows 8.1. It went away after I rolled back updates to about June 15. The problem is, the update process queues changes that don't take effect until a reboot, which makes it very tough to determine which KB item is the culprit. No one has seen the problem on Win7, and no one has tri...
- Tue Aug 04, 2015 4:45 pm
- Forum: Vensim
- Topic: FIND ZERO convergence issues with subscripts
- Replies: 4
- Views: 4749
Re: FIND ZERO convergence issues with subscripts
It seems like there ought to be an analytic solution, but I don't know it off the top of my head. You can separate the processing of the FIND ZERO subscripts by writing the equation to solve one element at a time (as in IRRGCC), but that would be a pain. A better approach, I think, is to detect the ...
- Tue Aug 04, 2015 4:18 pm
- Forum: Vensim
- Topic: How do i factor in efficiency losses in a model?
- Replies: 2
- Views: 1819
Re: How do i factor in efficiency losses in a model?
MODEL 1 b.mdl model 2 b.mdl In model 2, you're missing the outflow of process losses, so the losses "pile up" in the stock of WIP. I've modified to rectify that. In both models, there's an unaddressed question of whether managers know about the losses and adjust production to offset them....
- Tue Aug 04, 2015 3:51 pm
- Forum: Vensim
- Topic: FIND ZERO convergence issues with subscripts
- Replies: 4
- Views: 4749
Re: FIND ZERO convergence issues with subscripts
Is there a reason for not using the INTERNAL RATE OF RETURN function here?
- Sat Aug 01, 2015 2:18 pm
- Forum: Vensim
- Topic: Simulating specific subscripts
- Replies: 3
- Views: 2459
Re: Simulating specific subscripts
However, there is no way to selectively turn off a set of subscripts at runtime without changing model structure. Why do you need this? Maybe there's another way.
- Tue Jul 28, 2015 12:51 pm
- Forum: Ventity
- Topic: Installation Problems
- Replies: 5
- Views: 5655
Re: Installation Problems
We haven't posted it widely yet, but I'll PM it to you. You should have received a link in an email from ventity.biz - I'll check to be sure you're on the list.
- Sat Jul 25, 2015 7:21 pm
- Forum: Ventity
- Topic: Installation Problems
- Replies: 5
- Views: 5655
Re: Installation Problems
We'll fix the paths and release a new build as soon as everyone's back from the conference.
- Sat Jul 25, 2015 1:20 am
- Forum: Vensim
- Topic: Problems with "Find zero" convergence
- Replies: 13
- Views: 6167
Re: Problems with "Find zero" convergence
FIND ZERO dispatch.mdl The above setup might work. It needs demand/supply curves and parameters, but hopefully you can guess the intent from the units & names. The purpose of the "unserved" item is to permit convergence even in extreme conditions (low supply and inelastic high demand)...
- Sat Jul 25, 2015 12:12 am
- Forum: Vensim
- Topic: Problems with "Find zero" convergence
- Replies: 13
- Views: 6167
Re: Problems with "Find zero" convergence
I think the issue is that Difference Quantity isn't a vector. The first four arguments all need to have the same dimension. It should be possible to reformulate this problem to work, perhaps by computing a single shadow price and deriving exports from that. I'll have to think about it.
- Fri Jul 24, 2015 11:38 pm
- Forum: Ventity
- Topic: ventity.exe does not work
- Replies: 4
- Views: 4986
Re: ventity.exe does not work
Good that it works. We'll get a new build with the help link issue resolved as soon as we're back from the SD conference. I'll email an announcement to users and post here.
- Thu Jul 23, 2015 2:23 am
- Forum: Vensim
- Topic: Problems with "Find zero" convergence
- Replies: 13
- Views: 6167
Re: Problems with "Find zero" convergence
I'm happy to look at it after the SD conference.
- Thu Jul 23, 2015 2:06 am
- Forum: Ventity
- Topic: ventity.exe does not work
- Replies: 4
- Views: 4986
Re: ventity.exe does not work
My guess is that there is some issue with XP. As far as I know we have only tested on Win7 and Win8/8.1.
- Thu Jul 23, 2015 2:05 am
- Forum: Vensim
- Topic: about Ventity
- Replies: 3
- Views: 2780
- Wed Jul 22, 2015 9:32 pm
- Forum: Vensim
- Topic: Display subscripts values during synthesim
- Replies: 1
- Views: 2283
Re: Display subscripts values during synthesim
If you click on the slider arrow, you get a dialog that permits selecting a different element, but there's no way to show all at once. It's a feature we'd like too.