Noise Seed in Venapp

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Hossein
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Posts: 45
Joined: Thu Sep 15, 2016 7:50 am
Vensim version: DSS

Noise Seed in Venapp

Post by Hossein » Fri Oct 11, 2019 10:28 am

Dear Tom, Dear Administrator,

I would like to put a variable in my Venapp, that the user can change the Noise Seed and/or Number of Simulation before any sensitivity run. I was looking in Vensim parameters but there is not a Noise Seed and Number of Simulation (like INITIAL TIME) that can be changed through Venapp. Is it any possibility that I can do so?

BR,
Hossein

tomfid
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Re: Noise Seed in Venapp

Post by tomfid » Fri Oct 11, 2019 12:42 pm

Add NOISE SEED to the model and change it with SETVAL.
https://www.vensim.com/documentation/noise_seed.htm

Hossein
Member
Posts: 45
Joined: Thu Sep 15, 2016 7:50 am
Vensim version: DSS

Re: Noise Seed in Venapp

Post by Hossein » Mon Oct 14, 2019 7:32 am

Dear Tom,

but the problem is that the "Noise Seed" can be changed in the "Sensitivity Simulation Setup" window in Vensim as well as "Number of simulations". But in the Venapp, how should I connect my defined variable to Nose seed? Because in the Venapp, it is not possible to open the "Sensitivity Simulation Setup" window and make the changes! I would appreciate it if you could provide an example.

BR,
Hossein

Administrator
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Re: Noise Seed in Venapp

Post by Administrator » Mon Oct 14, 2019 9:06 am

Add a constant to the model called "NOISE SEED". You can now change this using SIMULATE>SETVAL. This overrides the value in the sensitivity setup window.
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tomfid
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Re: Noise Seed in Venapp

Post by tomfid » Mon Oct 14, 2019 2:52 pm

Hossein is correct - the sensitivity seed can't be changed programmatically. We should change that.

A workaround is to provide several different vsc files with different seeds. Another possibility is to use the vsc file to vary noise seed, and generate the distributions for the target variables inside the model, using the regular RANDOM functions.

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