Search found 1231 matches

by LAUJJL
Wed Nov 14, 2018 8:22 pm
Forum: Vensim
Topic: Changing the order of calculations
Replies: 10
Views: 46

Re: Changing the order of calculations

Hi Wanting to set the order of calculation, is like telling the computer to respect an order and another order at the same time, which is impossible to do. In fact, by writing the equations, you are telling the computer the order of calculation. For instance if d = a*b*c, before calculating d the pr...
by LAUJJL
Sun Nov 04, 2018 3:09 pm
Forum: Vensim
Topic: Aging chain with items taken out, on hold and put back
Replies: 20
Views: 181

Re: Aging chain with items taken out, on hold and put back

There was a mistake in my previous post.
i did not mean deserve deeply the field, but was deeply detrimental to the field
by LAUJJL
Sun Nov 04, 2018 9:00 am
Forum: Vensim
Topic: Aging chain with items taken out, on hold and put back
Replies: 20
Views: 181

Re: Aging chain with items taken out, on hold and put back

Hi Tom I totally agree with your point of view, except that you did not mention one of the characteristics of individual based methods: they are easier to test because they are a more exact representation of the reality making it possible to compare the exact reality to the model behaviour. Of cours...
by LAUJJL
Sat Nov 03, 2018 8:55 am
Forum: Vensim
Topic: Aging chain with items taken out, on hold and put back
Replies: 20
Views: 181

Re: Aging chain with items taken out, on hold and put back

Hi
It is difficult to chose between different solutions, without a deep knowledge of the problem.
Is it a real problem or an academic one?
If it is a real problem, we do not know what the model has to improve: financial, technical issues?
Regards.
JJ
by LAUJJL
Fri Nov 02, 2018 7:53 pm
Forum: Vensim
Topic: Aging chain with items taken out, on hold and put back
Replies: 20
Views: 181

Re: Aging chain with items taken out, on hold and put back

Hi In this model, you can generate two events every time step, and each event describes moving a definite quantity of widgets from one level to the other at a definite age. If you want to describe more events happening in a month, you must either reduce the time step, or add the subscript age to som...
by LAUJJL
Fri Nov 02, 2018 4:02 pm
Forum: Vensim
Topic: Aging chain with items taken out, on hold and put back
Replies: 20
Views: 181

Re: Aging chain with items taken out, on hold and put back

Hi It looks like a partly discreet problem, as you deal with individual delays. I personally avoid delays, because you have no information about what is in the delay. It is too impossible to step back in games with delays. In this case I use arrays, where I have a total control on what is happening....
by LAUJJL
Sat Oct 06, 2018 3:51 pm
Forum: Vensim
Topic: managing the display of a custom table
Replies: 4
Views: 136

Re: managing the display of a custom table

Hi I am rather annoyed not to have any reply because I am testing policies with the gaming tool, using external data to avoid the random generator to be reset, every time that one changes a gaming variable or if one steps back. Without any answer i will treat this problem as a bug and will try to fi...
by LAUJJL
Wed Oct 03, 2018 4:47 pm
Forum: Vensim
Topic: managing the display of a custom table
Replies: 4
Views: 136

Re: managing the display of a custom table

I join a simplistic model that illustrates two problems. The first problem is relative to the question of my preceding post. Suppose that I run the model joined in game mode, and I want to survey the value of stock in the table drawn in the sketch. It show up to 9 values. If I run the model past the...
by LAUJJL
Wed Oct 03, 2018 1:06 pm
Forum: Vensim
Topic: managing the display of a custom table
Replies: 4
Views: 136

Re: managing the display of a custom table

Hi Tom

thank you for the reply.

I will study it;

Best regards.

JJ
by LAUJJL
Mon Oct 01, 2018 4:46 pm
Forum: Vensim
Topic: managing the display of a custom table
Replies: 4
Views: 136

managing the display of a custom table

Hi Is it possible to control the data to be displayed in a custom table especially when gaming? For instance if I have custom table showing a variable and the custom table has a relatively small length for lack of space available, and the custom table shows only three values corresponding to three s...
by LAUJJL
Wed Sep 26, 2018 10:34 am
Forum: Vensim
Topic: Beer game model without subscripts
Replies: 2
Views: 97

Re: Beer game model without subscripts

thank you very much.

It helps a lot.

Best regards.

JJ
by LAUJJL
Wed Sep 26, 2018 9:20 am
Forum: Vensim
Topic: Beer game model without subscripts
Replies: 2
Views: 97

Beer game model without subscripts

Hi Tom

Are there any explanations somewhere for the beer game without subscripts model found in your metasd model library.

For instance I cannot see the meaning of the R,W,D and F processings; What are these R,W,D and F meaning?

Best regards.

JJ
by LAUJJL
Tue Sep 18, 2018 9:18 am
Forum: Vensim
Topic: System of differential equations-- estimating parameters
Replies: 22
Views: 422

Re: System of differential equations-- estimating parameters

Hi Simplifier. Another basic rule of SD that you do not respect: using constants with no significant name related to their meaning in the system that you pretend to describe. How can I understand a model where the author uses a1,b1,b2 etc.. without knowing what these constants are about? Best regard...
by LAUJJL
Tue Sep 18, 2018 8:53 am
Forum: Vensim
Topic: System of differential equations-- estimating parameters
Replies: 22
Views: 422

Re: System of differential equations-- estimating parameters

Hi Simplifier You have little chance of ever finding a solution of your problem, using a powerful software that you apparently do not master because of too little practice. When one practices Vensim a bit one finds very quickly the utility of putting units in models, and then doing it becomes a seco...
by LAUJJL
Fri Aug 31, 2018 5:27 pm
Forum: Vensim
Topic: Export and import data between Vensim and Excel
Replies: 11
Views: 260

Re: Export and import data between Vensim and Excel

HI

In which context are you building this model.

Will it be applied?

Regards.

JJ
by LAUJJL
Thu Aug 23, 2018 7:05 pm
Forum: Vensim
Topic: Export and import data between Vensim and Excel
Replies: 11
Views: 260

Re: Export and import data between Vensim and Excel

Hi

what is your problem?

Every year, I suppose that you have to take some décisions.

which décisions?

How is the cash flow of the year dependant from past Investments?

it would be useful to upload a very small model to illustrate your problem.

Regards.

JJ
by LAUJJL
Thu Aug 23, 2018 12:47 pm
Forum: Vensim
Topic: Export and import data between Vensim and Excel
Replies: 11
Views: 260

Re: Export and import data between Vensim and Excel

why do you want to calculate the IRR out of Vensim? Because the function exists in Excel? It is much simpler to calculate the IRR in Vensim, than exchanging data between vensim and excel. to calculate the IRR, you must find the zero of the NPV, that i think is calculated in Vensim. to find the rate ...
by LAUJJL
Sun Jul 15, 2018 8:07 am
Forum: Vensim
Topic: Subscript error
Replies: 6
Views: 245

Re: Subscript error

Hi

Did you try doing the modifications directly on the text model?

I have experienced some problems using the equation editor for the subscripts and working directly on the text équations is OK.

Regards.

JJ
by LAUJJL
Wed Jul 04, 2018 4:14 pm
Forum: Vensim
Topic: order of calculation of subscripts
Replies: 6
Views: 327

Re: order of calculation of subscripts

Hi

thank you for your answers.

Regards.

JJ
by LAUJJL
Wed Jul 04, 2018 10:05 am
Forum: Vensim
Topic: order of calculation of subscripts
Replies: 6
Views: 327

Re: order of calculation of subscripts

Hi The subscript represents time. I need this to calculate optimal policies each time period, using dynamic programming methods starting most of the time in the past (infinite horizon or not) and going backwards to the present. When one uses traditionnal mapping going from the past, if the number of...
by LAUJJL
Wed Jul 04, 2018 8:23 am
Forum: Vensim
Topic: order of calculation of subscripts
Replies: 6
Views: 327

Re: order of calculation of subscripts

Hi

This solution works if the subscript size is limited, although entering 100 individual equations is rather cumbersome, but if you have a subscript period: (p1-p1000) it is not tractable, especially if you want to modify the size of the subscript.

Regards.

JJ
by LAUJJL
Wed Jul 04, 2018 7:43 am
Forum: Vensim
Topic: order of calculation of subscripts
Replies: 6
Views: 327

order of calculation of subscripts

Hi

When you have a suscript like say period: (p1-p100) and vensim has to calculate for instance the variable var[period] it starts to calculate p1 then p2 etc…
Is there anyway to make Vensim calculate backwards p100 then p99 etc…

Regards.

JJ
by LAUJJL
Wed Jun 20, 2018 6:19 pm
Forum: Vensim
Topic: Single precision problem in Vensim PLE Plus?
Replies: 8
Views: 534

Re: Single precision problem in Vensim PLE Plus?

Hi It does not look like a problem of precision. I have joined the model with an intialization of the level to 100000. Whatever the format of the table, pretty or scientific and whatever its precision, the value for the level is not printed correctly, already at the beginning. If the value of the st...
by LAUJJL
Mon Jun 18, 2018 4:27 pm
Forum: Vensim
Topic: Single precision problem in Vensim PLE Plus?
Replies: 8
Views: 534

Re: Single precision problem in Vensim PLE Plus?

Hi

The level goes very quicky to 100000, in simple PLE and in Vensim DSS simple precision event starting the level at a 0 value!

I do not see where is the problem.

JJ
by LAUJJL
Thu Jun 14, 2018 3:09 pm
Forum: Vensim
Topic: Model Validation
Replies: 14
Views: 760

Re: Model Validation

there are already three tables in the model that show the behaviours of all the variables. You can generally add common or custom tables using the input/ouput oject. if you want to build custom tables you must go to the control panel and graphs and then build a custom table. You can too modify the e...