Re: [AMBER] Amber16 Parallel CUDA Tests

From: Ross Walker <ross.rosswalker.co.uk>
Date: Thu, 21 Jul 2016 10:34:19 +0100

Hi Steve,

Indeed that is too big a difference to just be rounding error - although if those tests are using Langevin or Anderson for the thermostat that would explain it (different random number streams) - although those tests are supposed to be skipped in parallel.

Can you send me a copy directly of your .log and .dif files for the 2 GPU run and I'll take a closer look at it.

All the best
Ross

> On Jul 20, 2016, at 21:19, Steven Ford <sford123.ibbr.umd.edu> wrote:
>
> Hello All,
>
> I currently trying to get Amber16 installed and running on our computing
> cluster. Our researchers are primarily interested in running the GPU
> accelerated programs. For GPU computing jobs, we have one CentOS 6.7 node
> with a Tesla K80.
>
> I was able to build Amber16 and run the Serial/Parallel CPU plus the Serial
> GPU tests with all file comparisons passing. However, only 5 parallel GPU
> tests succeeded, while the other 100 comparisons failed.
>
> Examining the diff file shows that some of the numbers are not off by much
> like the documentation said could happen. For example:
>
> 66c66
> < NSTEP = 1 TIME(PS) = 50.002 TEMP(K) = 351.27 PRESS =
> 0.
>> NSTEP = 1 TIME(PS) = 50.002 TEMP(K) = 353.29 PRESS =
> 0.
>
> This may also be too large to attribute to a rounding error, but it is a
> small difference compared to others:
>
> 85c85
> < Etot = -217.1552 EKtot = 238.6655 EPtot =
> -455.8207
>> Etot = -1014.2562 EKtot = 244.6242 EPtot =
> -1258.8804
>
> This was build with CUDA 7.5, OpenMPI 1.8, and run with DO_PARALLEL="mpirun
> -np 2"
>
> Any idea what else could be affecting the output?
>
> Thanks,
>
> Steve
>
> --
> Steven Ford
> IT Infrastructure Specialist
> Institute for Bioscience and Biotechnology Research
> University of Maryland
> (240)314-6405
> _______________________________________________
> AMBER mailing list
> AMBER.ambermd.org
> http://lists.ambermd.org/mailman/listinfo/amber


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Received on Thu Jul 21 2016 - 03:00:02 PDT
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