Hi, thank you for your answer... I tried but surely I made some mistakes somewhere. If I use RANDOM UNIFORM for the amplitude and the width is higher than TIME STEP I get random aplitudes within the same pulse and this is NOT what I want... Hope to have been clear...Administrator wrote:Have you tried using the RANDOM UNIFORM function to generate the numbers that you then feed to the pulse train?
First of all thank you. This is the "culprit":Administrator wrote:Can you post what you have done and explain what you need? I'm struggling to understand what you want to achieve.
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RN = RANDOM UNIFORM( minH , maxH, 0 )
PT = PULSE TRAIN(start, 1 , 6, FINAL TIME )
in0 = RN * PTThe calculations are correct. Why do you think they are wrong?Run it with TIME STEP << 1 h=3 and look at the flows in, f12 anf f2out. Do they behave as you would exepct? I think no.
Hi, first of all thank you...Administrator wrote:I'd start by separating out the "RANDOM UNIFORM( minH , maxH, 0 )*PULSE TRAIN(start, 1 , 6, FINAL TIME )" into two separate variables. It's impossible to debug when you cannot see what values are being generated by the functions.
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RN = RANDOM UNIFORM( minH , maxH, 0 ) PT = PULSE TRAIN(start, 1 , 6, FINAL TIME ) in0 = RN * PTThe calculations are correct. Why do you think they are wrong?Run it with TIME STEP << 1 h=3 and look at the flows in, f12 anf f2out. Do they behave as you would exepct? I think no.
I'm looking for pulses with random height and width that repeat with a random generated period but within each width I want a pulse to have a constant value.tomfid wrote: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.
Here it's one: a succession of groups, one idependent from the others, arriving at a service; each group with different size, the groups arriving with varying frequencies but each within a variable period of time....but you can also use it to describe sudden rainfalls or bursts of any type that occur with variable frequency, every burst with it's own duration and constant intensity...tomfid wrote: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?
Unfortunately [for me] I use Vensim PLE...tomfid wrote: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.
Hi JJLAUJJL wrote:It is possible to emulate the sample if true function in PLE.
Joined the model in mdl and vpm format tthat demonstrates it and that can be read with the Vensim player, if you cannot run the .mdl model in PLE.
Regards.
JJ
many thanks.... I download the models and try to understand them....