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Re: [lammps-users] GPU for granular simulations
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Re: [lammps-users] GPU for granular simulations


From: Axel Kohlmeyer <akohlmey@...24...>
Date: Thu, 29 Jun 2017 07:53:35 -0400

On Thu, Jun 29, 2017 at 7:51 AM, habib rahbari
<habib.rahbari@...444...> wrote:
> Dear Axel,
>
> Thanks for your kind response.
>
> You mean there is no support for granular pair forces by GPU LAMMPS?

where does it say there is?

axel.

>
>
>
>
> On Thu, Jun 29, 2017 at 7:44 AM, Axel Kohlmeyer <akohlmey@...24...> wrote:
>>
>> On Wed, Jun 28, 2017 at 10:28 PM, habib rahbari via lammps-users
>> <lammps-users@lists.sourceforge.net> wrote:
>> > Dear Developers,
>> >
>> > I am running a granular frictionless short range repulsion simulation:
>> >
>> > pair_style      gran/hooke 1 0  1 0 0 0
>> > pair_coeff      * *
>> >
>> > We have installed LAMMPS GPU on  our CUDA cluster which is:
>> >
>> > GPU : Nvidia Tesla m2050 (1.15 GHz, 448) * 4EA
>> >
>> > Each machine has 4 cores, so I need to use MPI to get the full machine:
>> >
>> > # Set parallel environment (pe) to OpenMPI (opmi) and number of cores
>> > required.
>> > #$ -pe gpu_openmpi 4
>> >
>> > and then I use the following command to run the code:
>> >
>> > /home/program/lammps/lmp_gpu -sf gpu -pk gpu 1 -in in.file
>>
>> this is a pointless enterprise. there currently is no GPU acceleration
>> for any granular pair style in LAMMPS. your gpu suffix flag has no
>> effect.
>>
>> >
>> > However, I get the following error:
>> >
>> > /home/program/lammps/lmp_gpu: symbol lookup error:
>> > /opt/intel//impi/5.0.1.035/intel64/lib/libmpifort.so.12: undefined
>> > symbol:
>> > MPI_UNWEIGHTED
>> >
>> > Is this because pair_style   gran/hooke apparently has no GPU speed up?
>>
>> no. this looks like you have an incompatible version of the _intel_
>> (!!) mpi runtime library in your LD_LIBRARY_PATH environment, that
>> differs from the version your executable was compiled with. this
>> conflicts with your claim, that you were using OpenMPI.
>>
>> > Or it is the installation problem on GPU?
>>
>> it is a compilation/installation problem.
>>
>> > I see in the net that people have already used GPU for granular
>> > simulations,
>>
>> but they must have used a different software or not shared their
>> implementation with the LAMMPS developers.
>> whatever is written "somewhere in the internet" is irrelevant here.
>> what matters is what the LAMMPS manual says: whatever is not mentioned
>> is not there; no feature is added to LAMMPS without documenting it.
>>
>> axel.
>>
>> > but style hooke has no explicit GPU extension.
>> >
>> > In advance, I appreciate your kind help!
>> >
>> >
>> >
>> >
>> >
>> > ------------------------------------------------------------------------------
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>> > _______________________________________________
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>> > lammps-users@lists.sourceforge.net
>> > https://lists.sourceforge.net/lists/listinfo/lammps-users
>> >
>>
>>
>>
>> --
>> Dr. Axel Kohlmeyer  akohlmey@...24...  http://goo.gl/1wk0
>> College of Science & Technology, Temple University, Philadelphia PA, USA
>> International Centre for Theoretical Physics, Trieste. Italy.
>
>
>
>
> --
> http://newton.kias.re.kr/~habib/



-- 
Dr. Axel Kohlmeyer  akohlmey@...24...  http://goo.gl/1wk0
College of Science & Technology, Temple University, Philadelphia PA, USA
International Centre for Theoretical Physics, Trieste. Italy.