More pulse queries.

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nikvyas
Senior Member
Posts: 112
Joined: Mon Apr 24, 2006 3:17 pm

More pulse queries.

Post by nikvyas »

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[Edited on 12-8-2006 by nikvyas]
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LAUJJL
Senior Member
Posts: 1427
Joined: Fri May 23, 2003 10:09 am
Vensim version: DSS

Fixed pulses

Post by LAUJJL »

Hi Nik

It would be a good idea, if you want some help, to first simplify you problem to the utmost possible to deliver a highly simplified model, (no errors with both C and U checkings) and with full explanation of every variable and every equation.
That simplified model does not need to represent your overall problem but just your technical diffculty.
It is too a good idea to represent every level or delay with a
box with the input and output with rates clearly sketched.
It is easier to understand.
What do you mean by sortie?
how are the pulses fixed? Fixed because occuring regularly of having a fixed duration.
A good idea would be too to explain exactly the reality that the model is supposed to represent.
It will be the easier to understand what you want.
You understand probably well your problem but other people do not!
Regards.
JJ
nikvyas
Senior Member
Posts: 112
Joined: Mon Apr 24, 2006 3:17 pm

Post by nikvyas »

Sorry JJ - you are quite right.
LAUJJL
Senior Member
Posts: 1427
Joined: Fri May 23, 2003 10:09 am
Vensim version: DSS

Pulses

Post by LAUJJL »

Hi Nik

You should too use subscripts to simplify the presentation of your model.
At this stage, this kind of model is extremely difficult to manage and using subscripts will considerably ease the writing of the equations and help to understand the model.

I hope that you have at least the pro version, otherwise you will have real difficulties without subscripts.
Regards.
JJ
nikvyas
Senior Member
Posts: 112
Joined: Mon Apr 24, 2006 3:17 pm

Post by nikvyas »

Hi JJ.

yes - we have the Pro version (recently ordered three more copies). I've tried to avoid using subscripts up till now, because I found it to complicate matters further. However, I'm sure that after getting used to them, they will be a great help.

Thanks

Nik
LAUJJL
Senior Member
Posts: 1427
Joined: Fri May 23, 2003 10:09 am
Vensim version: DSS

using subscripts

Post by LAUJJL »

Hi Nik

Using subscripts is not straightforward and needs practice.
You must learn especially how to use the mapping techniques and the vector elm map function.
One good idea would be to simplify your model to the point
where you can draw a parallel with it and reality even if the reality is highly aggregated.
Being not experienced with SD, you are falling in the trap of
thinking that the more your model will simulate 'exactly reality' the more it will help you.
The more you will try to simulate reality the more your model gets complicated and the more it is complex, the more it is
difficult to understand up to a point where it does not deliver any understanding at all.
A model that is useful must be understandable.
Regards.
JJ.
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