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Re: [lammps-users] Using pair style hybrid with GPU
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Re: [lammps-users] Using pair style hybrid with GPU


From: Xiaoyu Wang <xwang181@...5818...>
Date: Wed, 20 Sep 2017 15:13:30 -0500

So I tried “package gpu split” command which will work. Am I right if I am saying that gpu package does not support hybrid because the neighbor list cannot be built on GPU in the case and all the bond,angle,improper,long-range will not work either? So what I can do is let CPU run the neighbor and hybrid pair style and leave the GPU-enabled pair style only by using "split 1”.

On Sep 20, 2017, at 2:15 PM, Axel Kohlmeyer <akohlmey@...24...> wrote:

On Wed, Sep 20, 2017 at 3:06 PM, Xiaoyu Wang <xwang181@...5818...> wrote:
Hi Axel,

1. I am thinking that some styles are not supported by GPU so I put intel package as an alternative.

that makes no sense. there are specific rules that LAMMPS follows
strictly. any kind of "just-in-case" commands are pointless.

2. I tried to remove the /gpu suffixes but left the package gpu command in the input. It worked.

that is similarly pointless. if you are not using any suffixes, you
are not using the GPU. you can tell from the screen output what is
going on.

but if your input works on the CPU, you can use the command line flags
-sf and -pk to automatically have the suffixes applied and the package
command issued.

My question is:
Do I need to specify /gpu after I put gpu package in the script or just let the program decide it should use gpu or not. The same question also comes for the k_space command. Do I need to put pppm/gpu and package gpu together or just state once?

this is all explained at great length in the documentation. there is
no much sense in repeating it here. read the manual! carefully!!
multiple times!!!
there is the "getting started" section, there is a section for
acceleration, there is a section for packages and then there are the
individual commands.
so get reading, and practice with some simpler inputs (e.g. the
examples given in the "bench" folder) and work your way up to your
rather complex setup.


axel.



Thanks

On Sep 20, 2017, at 1:53 PM, Axel Kohlmeyer <akohlmey@...24...> wrote:

On Wed, Sep 20, 2017 at 2:44 PM, Xiaoyu Wang <xwang181@...5818...> wrote:
Dear all,

I tried to use GPU package with pair style hybrid. Some of them are using
buck/coul/long/gpu and some of them are using lj/cut/coul/long/gpu. But I
received the error:

ERROR: Pair coeff for hybrid has invalid style (../pair_hybrid.cpp:393)

Then I tried to use intel and gpu package together, but it seems that intel
does not support pair_style hybrid either. So can some one recommend me the
best way to accelerate my script or what kind of packages should I build and
how to write the script to use both GPU and CPU.

I will appreciate your help. Thanks!

This is what I wrote in my script regarding the acceleration part.

two comments/questions:

1: why do you request the intel package, when you are not using any
/intel styles?
2: does your input work without the package commands and the /gpu suffixes?

axel.


package gpu 1 neigh no
package intel 18
pair_style hybrid buck/coul/long/gpu 12.0 lj/cut/coul/long/gpu 12.0
pair_coeff      1       1       lj/cut/coul/long/gpu    0.5000  3.40
pair_coeff      2       2       lj/cut/coul/long/gpu    0.3000  2.40
pair_coeff      3       3       buck/coul/long/gpu      31532.571
0.2899  0

Shaw

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--
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.




-- 
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.