Vensim 8 without single precision?

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pav80
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Vensim 8 without single precision?

Post by pav80 » Wed Nov 06, 2019 12:05 pm

Greetings,

On this site https://vensim.com/september-newsletter ... -releases/ it mentions
"All configurations of Vensim now use double floating point precision for both calculations and results storage"

So does that mean as of Vensim 8, single precision is no longer available or it is possible to select it as an option?

Asking because this link https://www.vensim.com/documentation/24350.htm mentions
"For large models the double precision version of Vensim essentially takes twice the memory, so it should be used with discretion. For most business models there seems little to be gained from the added precision."

Thank you.

Administrator
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Re: Vensim 8 without single precision?

Post by Administrator » Wed Nov 06, 2019 12:45 pm

Correct, single precision is no longer an option. Due to some of the code in Vensim, the 64 bit version of Vensim has to be double precision.
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pav80
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Re: Vensim 8 without single precision?

Post by pav80 » Wed Nov 06, 2019 2:34 pm

Thank you for the confirmation.

Do you also confirm that "For large models the double precision version of Vensim essentially takes twice the memory, so it should be used with discretion. For most business models there seems little to be gained from the added precision." ? Taken from https://www.vensim.com/documentation/24350.htm

Perhaps this link needs to be updated since single precision is no longer available.

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Re: Vensim 8 without single precision?

Post by Administrator » Wed Nov 06, 2019 2:38 pm

It's not quite double the memory. It depends on the model and how many variables are being stored, plus how often the values change.
Advice to posters seeking help (it really helps us to help you)
http://www.ventanasystems.co.uk/forum/v ... f=2&t=4391

Units are important!
http://www.bbc.co.uk/news/magazine-27509559

pav80
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Re: Vensim 8 without single precision?

Post by pav80 » Wed Nov 06, 2019 2:55 pm

Thanks Aministrator

tomfid
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Re: Vensim 8 without single precision?

Post by tomfid » Wed Nov 06, 2019 4:10 pm

Also, the memory limit is only significant for very large models, and that's now relieved by the availability of 64-bit Vensim, which can access memory far exceeding what's practical to run.

pav80
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Re: Vensim 8 without single precision?

Post by pav80 » Wed Nov 06, 2019 4:12 pm

Thanks Administrator

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