Questions on Nbody
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Message 64371 - Posted: 10 Mar 2016, 19:17:40 UTC
Last modified: 10 Mar 2016, 19:18:16 UTC

Run time seems varies by a lot. I checked computation size and they were similar, but wall time varies too much, one can be finish in 10 minutes and the other took 10+ hours. Another thing I noticed is that when I run Nbody task, the handles in task manager skyrockets, right now it is at 1 million...

Profile Jake Weiss
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Message 64806 - Posted: 5 Jul 2016, 13:32:11 UTC


The run time varies a lot because the step size in the simulation depends on the parameters going into the simulation. This means for some parameter combinations, there are fewer steps than other parameter combinations. This leads to varying simulations times. Sidd should be trying to keep the simulations from hitting excessively large simulation times, but it seems he didn't do a good enough job for this simulation.

I will talk to Sidd and remind him to be nice to you guys and keep the simulations to reasonable times.


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Message 64814 - Posted: 5 Jul 2016, 16:59:01 UTC

It's worth noting that you do get more credit for the longer N-Body tasks.

How credit is computed is way too complicated to get into here, but suffice to say that you're getting roughly the same amount of credit per amount of time, regardless of how long the tasks take.

For me, in this last round of N-Body, I've seen tasks as short as about 2 minutes and as long as 170 hours (on the same machine, I might add) so as long as yours are falling inside that, it's probably all good. :-)

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