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Re: sensitivity analysis (vensim)

Posted: Tue Oct 08, 2019 3:06 pm
by RWTH_FCN
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?

Re: sensitivity analysis (vensim)

Posted: Mon Oct 14, 2019 5:24 pm
by tomfid
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.

Re: sensitivity analysis (vensim)

Posted: Thu Oct 17, 2019 3:56 pm
by RWTH_FCN
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.

Re: sensitivity analysis (vensim)

Posted: Mon Oct 28, 2019 5:12 pm
by RWTH_FCN
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?

Re: sensitivity analysis (vensim)

Posted: Mon Oct 28, 2019 5:44 pm
by tomfid
Any chance that the disk really is full (or would be, after writing the results)?

Re: sensitivity analysis (vensim)

Posted: Tue Oct 29, 2019 6:47 pm
by RWTH_FCN
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

Re: sensitivity analysis (vensim)

Posted: Tue Oct 29, 2019 7:09 pm
by tomfid
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?

Re: sensitivity analysis (vensim)

Posted: Tue Oct 29, 2019 8:41 pm
by tomfid
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?

Re: sensitivity analysis (vensim)

Posted: Wed Oct 30, 2019 6:39 pm
by RWTH_FCN
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.

Re: sensitivity analysis (vensim)

Posted: Tue Nov 05, 2019 3:50 pm
by tomfid
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.

Re: sensitivity analysis (vensim)

Posted: Wed Nov 20, 2019 4:34 pm
by RWTH_FCN
tomfid wrote: 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.
Sorry for late response. Actually, I used increased version of SAVEPER. For my case, as long as the model is huge (simulation of compiled version takes around 20 minutes) implementing Monte carlo and stochastic optimization is a big deal in Vensim.