Search found 3206 matches

by tomfid
Wed Mar 03, 2021 9:41 pm
Forum: Vensim
Topic: Vensim introducing backslashes in Var names before each underbar. Bug?
Replies: 6
Views: 65

Re: Vensim introducing backslashes in Var names before each underbar. Bug?

I'd completely forgotten about it, but there's one more setting to check:
2021-03-03_14-38-35.png
2021-03-03_14-38-35.png (8.49 KiB) Viewed 1 time
This might explain why you only have trouble with the one model.
by tomfid
Mon Mar 01, 2021 2:23 pm
Forum: Vensim
Topic: Vensim introducing backslashes in Var names before each underbar. Bug?
Replies: 6
Views: 65

Re: Vensim introducing backslashes in Var names before each underbar. Bug?

A few: - If you look at it with a text editor, does the troublesome model start with {UTF-8} consistently? Mixing pre- and post-unicode versions of Vensim could be an issue. - Try a Model>Reform & Clean before you start editing to see if the problem goes away (but be cautious before checking in, as ...
by tomfid
Mon Mar 01, 2021 12:14 am
Forum: Vensim
Topic: Sample model “SAMPLE IF TRUE” not working
Replies: 2
Views: 30

Re: Sample model “SAMPLE IF TRUE” not working

The warning happens because there's a different draw from the random number generator in the initialization step and the first time step. That changes the random value of workforce used to initialize the sampling. In a more normal deterministic model, that wouldn't happen.
by tomfid
Sun Feb 28, 2021 4:07 pm
Forum: Vensim
Topic: I'm having the following problem
Replies: 2
Views: 38

Re: I'm having the following problem

Another option, if the data is for comparison, is to use the Reference Mode tool.
by tomfid
Wed Feb 24, 2021 3:01 pm
Forum: Vensim
Topic: Vensim introducing backslashes in Var names before each underbar. Bug?
Replies: 6
Views: 65

Re: Vensim introducing backslashes in Var names before each underbar. Bug?

I think your comments explain why I couldn't replicate this in a new model. 1. As far as I can tell from experimentation, the only problematic combination is an escaped underbar added manually (with underbars off). It doesn't cause crashes or parse failures, but it does persist unnecessarily. I coul...
by tomfid
Wed Feb 24, 2021 2:47 pm
Forum: Vensim
Topic: Error Running Simulation
Replies: 2
Views: 31

Re: Error Running Simulation

Is Water In Lake initialized to an expression that uses Precipitation and/or Evaporation?
by tomfid
Tue Feb 23, 2021 4:32 pm
Forum: Vensim
Topic: Delay Function cannot shut off flow using a test for negative stock level.
Replies: 6
Views: 320

Re: Delay Function cannot shut off flow using a test for negative stock level.

I think the oscillation is due to the discrete logic in the outflow constraint. You have: intestinal Flow Rate= IF THEN ELSE( Time<8 :OR: Intestines<=0 , 0 , gut flow) This enforces "nothing in intestines, no outflow" but it doesn't enforce "tiny amount in intestines, limited outflow". A better cons...
by tomfid
Mon Feb 22, 2021 4:42 pm
Forum: Vensim
Topic: Vensim introducing backslashes in Var names before each underbar. Bug?
Replies: 6
Views: 65

Re: Vensim introducing backslashes in Var names before each underbar. Bug?

I haven't checked the logs yet to see if we've changed any of these behaviors, but I doubt it. I can replicate your model by typing an explicit underbar in a new variable name, when underbars are turned off. It's sensible that an escape character (\) is needed in this case. However, I can't replicat...
by tomfid
Sat Feb 20, 2021 4:50 am
Forum: Vensim
Topic: Table Tool Menu in Ver 8 +
Replies: 4
Views: 62

Re: Table Tool Menu in Ver 8 +

You can still right-click the tool to change settings. Or is there some other menu action you're after?
by tomfid
Sat Feb 20, 2021 4:49 am
Forum: Vensim
Topic: vdfx needed for Vensim 8+? vdf2vdfx?
Replies: 8
Views: 247

Re: vdfx needed for Vensim 8+? vdf2vdfx?

If you have an example, we would be happy to have a copy for testing - upload or email works.
by tomfid
Fri Feb 19, 2021 3:19 pm
Forum: Vensim
Topic: Allocation function failed to converge computing
Replies: 5
Views: 1054

Re: Allocation function failed to converge computing

The allocation is essentially creating an aggregate supply and demand curve, then finding the intersection. https://www.vensim.com/documentation/24325.html If the distance between the priorities is much greater than the width, you get curves with intermittent flat spots. That makes it hard for the a...
by tomfid
Thu Feb 18, 2021 2:49 pm
Forum: Vensim
Topic: Vensim dll + R
Replies: 2
Views: 300

Re: Vensim dll + R

It's hard to believe it hasn't been done, but I haven't seen it.
by tomfid
Tue Feb 16, 2021 7:41 pm
Forum: Ventity
Topic: Multi-echelon structure
Replies: 7
Views: 245

Re: Multi-echelon structure

Figured it out. The problem seems to be a bug in the Excel reader when there are spaces in the entity/tab names. As a workaround, getting rid of the space gets this running.
Level 3.zip
(161.12 KiB) Downloaded 9 times
by tomfid
Tue Feb 16, 2021 7:24 pm
Forum: Ventity
Topic: Multi-echelon structure
Replies: 7
Views: 245

Re: Multi-echelon structure

With Model 3.xlsx, I see a bunch of errors like: 02/16/2021 12:15:11: Run 'Run' at time [0] - Null reference ndc_stock in ndc2rdc[NDC1|RDC1|SKU1] using "NDC1|SKU1". This may cause other errors and warnings. The cause seems to be that there are no NDC Stock entities (you can see this in the entity pi...
by tomfid
Tue Feb 16, 2021 7:12 pm
Forum: Ventity
Topic: Multi-echelon structure
Replies: 7
Views: 245

Re: Multi-echelon structure

There's no hard limit to initialization data; you're limited by memory and computation time for the entities they define. The limit to those things depends on the size of the entities (# of equations) but generally 1000 is easy and 1000000 is going to be very slow. One limitation of the current arch...
by tomfid
Mon Feb 15, 2021 4:06 am
Forum: Vensim
Topic: VECTOR SELECT unweighted units
Replies: 2
Views: 60

Re: VECTOR SELECT unweighted units

I think you're correct, at least in principle. However, I think there's also a good argument for maintaining parallel between the weighted and unweighted aggregation units (the first six and the 2nd six). The PROD methods are a bit problematic, because the units vary with the dimensionality of the a...
by tomfid
Sat Feb 13, 2021 7:20 pm
Forum: Vensim
Topic: Passing string constants through a data file
Replies: 13
Views: 282

Re: Passing string constants through a data file

The model has

part : (p1-p2)

so the error for p3 is expected.

However, we can downgrade it to a warning so that it still runs.
by tomfid
Sat Feb 13, 2021 4:54 pm
Forum: Vensim
Topic: Floating point error source not being shown
Replies: 3
Views: 89

Re: Floating point error source not being shown

It may not be known, because optimization and sensitivity runs preserve less information for the sake of speed, but I agree that this is a useful request. I'll see what's possible.
by tomfid
Sat Feb 13, 2021 4:52 pm
Forum: Vensim
Topic: Passing string constants through a data file
Replies: 13
Views: 282

Re: Passing string constants through a data file

Right - the syntax should be the same as an equation: = for numbers, :is: for strings.
by tomfid
Fri Feb 12, 2021 11:24 pm
Forum: Vensim
Topic: Passing string constants through a data file
Replies: 13
Views: 282

Re: Passing string constants through a data file

One other option: use GET XLS SUBSCRIPTS or the GET DIRECT equivalent to define them.
by tomfid
Fri Feb 12, 2021 9:18 pm
Forum: Vensim
Topic: Problem with subscripts being lost
Replies: 6
Views: 112

Re: Problem with subscripts being lost

Exactly - kudos to Tony for creating the new control, I think (nothing to do with me).
by tomfid
Fri Feb 12, 2021 5:14 pm
Forum: Vensim
Topic: Passing string constants through a data file
Replies: 13
Views: 282

Re: Passing string constants through a data file

What's the use case for this?
by tomfid
Fri Feb 12, 2021 4:59 pm
Forum: Vensim
Topic: Passing string constants through a data file
Replies: 13
Views: 282

Re: Passing string constants through a data file

I think data i/o only works for numeric values. Strings would have to be in a .cin.
by tomfid
Fri Feb 12, 2021 4:26 pm
Forum: Vensim
Topic: Variable value for each timestep VENSIM PLE
Replies: 11
Views: 225

Re: Variable value for each timestep VENSIM PLE

There are deep discounts for academic and public research purposes. You can shoot us an email at vensim at vensim.com for a quote. Possibly there's an unused copy at your institution?
by tomfid
Fri Feb 12, 2021 4:13 pm
Forum: Vensim
Topic: Problem with subscripts being lost
Replies: 6
Views: 112

Re: Problem with subscripts being lost

In general, whether you want a single master range with overlapping subranges, or distinct ranges, depends on whether you'll ever use the master range. If, for example, you want to calculate SUM(distance[all trips!]) the master range would be convenient. On the other hand, if rural and urban trips h...