Help please-Calculating number of reinforcing/balancing loops passing a variable in VENSIM PLE

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Thanh
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Joined: Wed Jan 09, 2019 12:29 pm
Vensim version: PLE

Help please-Calculating number of reinforcing/balancing loops passing a variable in VENSIM PLE

Post by Thanh » Sun Sep 22, 2019 4:00 am

Hi everyone,
Has anyone tried to calculate number of reinforcing or balancing loops passing a specific variable in a system?
I have built a conceptual model and identified some key variables. I now want to check whether reinforcing loops or balancing loops dominate that variable, however there are too many loops involved that variable (~200 loops). It seems impossible to manually count every single loop to identify either reinforcing or balancing for about 5 variables as it will come up about 1000 loops.

Is there any way we can know a loop belongs to reinforcing or balancing without counting everylink relating a variable?
I appreciate any comment or suggestion.

Regards,
Thanh

tomfid
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Re: Help please-Calculating number of reinforcing/balancing loops passing a variable in VENSIM PLE

Post by tomfid » Mon Sep 23, 2019 5:00 pm

You can use the loops tool to count the total number of loops, but not their polarity.

Can you describe your purpose for doing this?

I think what you may really need is eigenvector analysis: https://pdfs.semanticscholar.org/58b4/c ... 845f28.pdf

Thanh
Junior Member
Posts: 4
Joined: Wed Jan 09, 2019 12:29 pm
Vensim version: PLE

Re: Help please-Calculating number of reinforcing/balancing loops passing a variable in VENSIM PLE

Post by Thanh » Wed Sep 25, 2019 2:46 am

Hi tomfid, Thanks for your rep.
The purpose of counting number of reinforcing and balancing loops for a particular variable is to identify which type of loop dominate that variable.
Then I can qualitatively assess the system behaviour/stability one I have know dominance loops for key variables.

Should this your company develop an add-on function to VENSIM in the near future?
I could not download the pdf file, could you please re-send it. Thank you

Regards,
Thanh

tomfid
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Re: Help please-Calculating number of reinforcing/balancing loops passing a variable in VENSIM PLE

Post by tomfid » Wed Sep 25, 2019 3:54 am

Unfortunately knowing the number of loops isn't helpful, because many weak loops could be dominated by one strong loop.

You might try this link instead: https://papers.ssrn.com/sol3/papers.cfm ... id=3114407

tomfid
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Re: Help please-Calculating number of reinforcing/balancing loops passing a variable in VENSIM PLE

Post by tomfid » Wed Sep 25, 2019 3:54 am

This is something we're exploring but it's not on the road map yet.


Thanh
Junior Member
Posts: 4
Joined: Wed Jan 09, 2019 12:29 pm
Vensim version: PLE

Re: Help please-Calculating number of reinforcing/balancing loops passing a variable in VENSIM PLE

Post by Thanh » Thu Oct 10, 2019 12:02 pm

Thank you,
I will read those refs.

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