MPI potential

conda-forge availability

The conda-forge package omits MPI. Build from source with -Dwith_mpi=enabled.

Note

This is only for modified VASP at the moment..

VASP

If you have access to the modified VASP source code that is compatible with eOn, you can compile a version of VASP that will work with eOn. This can be accomplished by compiling with make MPMD=1.

That VASP binary joins the eOn client in one MPI job. A standalone client sets EON_CLIENT_STANDALONE. The client count is then 1, so the run does not read EON_NUMBER_OF_CLIENTS. The client loads config_0.ini when that file exists, and config.ini otherwise. The MPI communicator leaves EON_CLIENT_STANDALONE unset and sets EON_NUMBER_OF_CLIENTS and EON_SERVER_PATH, as on the communicator page. Each client still gets the VASP output directory described next.

Each group of VASP ranks will write its output to a directory named vasp### where the number that follows is a zero-padded number that ranges from zero to EON_NUMBER_OF_CLIENTS. There is a script in the tools directory named mkvasp.py that takes the number of clients and a path and then creates these directories in that path.

An INCAR file must be prepared that has the following lines in addition to any other settings you wish to specify:

IBRION=3
POTIM=0
LMPMD=.TRUE.
NSW=99999999
EDIFF=1E-7
EDIFFG=-1e-6
LWAVE=.FALSE.
LCHARG=.FALSE.

[Potential] potential = mpi selects this interface. A build without -Dwith_mpi=enabled has no such potential, and the client stops with No known potential could be constructed. The number of vasp_mpmd ranks must be a positive multiple of the client count. [Potential] mpi_poll_period is the wait between probes, in seconds. The default is 0.25.

Example

Eight VASP ranks and one client:

#!/bin/sh
mkdir vasp000
export EON_CLIENT_STANDALONE=1
mpirun -n 8 vasp_mpmd : -n 1 eonclient

[Main]
job = point

[Potential]
potential = mpi

job = point reads pos.con from that working directory.