sensitivity analysis (vensim)

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RWTH_FCN
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Re: sensitivity analysis (vensim)

Post by RWTH_FCN » Tue Oct 08, 2019 3:06 pm

I ran the model on a super computer but since this version does not do any parallel multicore computation, the running time did not reduce. Do you have any plan for releasing that experimental version?

tomfid
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Re: sensitivity analysis (vensim)

Post by tomfid » Mon Oct 14, 2019 5:24 pm

We're working on it, but I'm not sure whether it'll be done by end of year. The speedup is more than noticeable if you have a many-core machine. Older workstations with 16 or more cores are now readily available at dirt cheap prices. We'll keep you posted as this evolves.

RWTH_FCN
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Re: sensitivity analysis (vensim)

Post by RWTH_FCN » Thu Oct 17, 2019 3:56 pm

tomfid wrote:
Mon Oct 14, 2019 5:24 pm
We're working on it, but I'm not sure whether it'll be done by end of year. The speedup is more than noticeable if you have a many-core machine. Older workstations with 16 or more cores are now readily available at dirt cheap prices. We'll keep you posted as this evolves.
Thanks for your information.

RWTH_FCN
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Posts: 113
Joined: Wed Feb 08, 2017 9:10 am
Vensim version: DSS

Re: sensitivity analysis (vensim)

Post by RWTH_FCN » Mon Oct 28, 2019 5:12 pm

Hi,

I did Monte carlo Simulation for a large-scale model, after many simplifications in my model I got this error (it happens at Sensitivity Simulation 1/3):

error writing results-disk may be full

I was wondering is there any solution for it or is it related to size of model?

tomfid
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Re: sensitivity analysis (vensim)

Post by tomfid » Mon Oct 28, 2019 5:44 pm

Any chance that the disk really is full (or would be, after writing the results)?

RWTH_FCN
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Vensim version: DSS

Re: sensitivity analysis (vensim)

Post by RWTH_FCN » Tue Oct 29, 2019 6:47 pm

tomfid wrote:
Mon Oct 28, 2019 5:44 pm
Any chance that the disk really is full (or would be, after writing the results)?
I don't think so. Maybe it is related to the size of model

tomfid
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Re: sensitivity analysis (vensim)

Post by tomfid » Tue Oct 29, 2019 7:09 pm

Are you using 32 or 64 bit Vensim? If you do a run with only 1 sensitivity instance (if you can), how big is the file size increment over a non-sensitivity vdf file?

tomfid
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Re: sensitivity analysis (vensim)

Post by tomfid » Tue Oct 29, 2019 8:41 pm

Actually, I see that the error happens on sim 1. Looking at the code, the counter for writing sensitivity result blocks is an integer, which will impose a 2 gigabyte limit per simulation. Any chance you're near that?

RWTH_FCN
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Posts: 113
Joined: Wed Feb 08, 2017 9:10 am
Vensim version: DSS

Re: sensitivity analysis (vensim)

Post by RWTH_FCN » Wed Oct 30, 2019 6:39 pm

tomfid wrote:
Tue Oct 29, 2019 7:09 pm
Are you using 32 or 64 bit Vensim? If you do a run with only 1 sensitivity instance (if you can), how big is the file size increment over a non-sensitivity vdf file?
I am using 32 bit now. The problem occures when I increase number of iterations. I think your assumption is correct, when size of vdf reaches 2 Gb it produces that error.

tomfid
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Re: sensitivity analysis (vensim)

Post by tomfid » Tue Nov 05, 2019 3:50 pm

Can you increase the SAVEPER or thin out the savelist a bit? If you're getting gigabytes of output from a one or two simulations, it'll be pretty unwieldy when there are many.

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