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


From: habib rahbari <habib.rahbari@...444...>
Date: Thu, 29 Jun 2017 07:51:13 -0400

Dear Axel,

Thanks for your kind response.

You mean there is no support for granular pair forces by GPU LAMMPS?




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@...429...96...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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--
Dr. Axel Kohlmeyer  akohlmey@...43...4...  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/