MPI RUN

Dear users
I installed lammps on ubuntu 12.04 by using instructions on download page of lammps website.the instalation completed and below warning was apaered.
WARNING: OMP_NUM_THREADS environment is not set. (…/comm.cpp:100)
using 1 OpenMP thread(s) per MPI task

what does it mean?and how can i use mpirun?
thanks

Dear users
I installed lammps on ubuntu 12.04 by using instructions on download page
of lammps website.the instalation completed and below warning was apaered.
WARNING: OMP_NUM_THREADS environment is not set. (../comm.cpp:100)
  using 1 OpenMP thread(s) per MPI task

what does it mean?

exactly what it says. the OMP_NUM_THREADS environment variable is not
set (same as on most machines). it is irrelevant unless you want to do
multi-threading via OpenMP, but if you wanted that, you would already
know what OMP_NUM_THREADS stands for.

and how can i use mpirun?

this has nothing to do with mpirun.

axel.

I posted the makefiles I used to compile lammps with MPI in ubuntu here:
http://lammps.sandia.gov/threads/msg36437.html

I think the makefiles posted there still work.
However my instructions for installing packages using apt-get are wrong.
Try this instead:

sudo apt-get install build-essential fftw-dev gfortran

--- getting MPI installed on ubuntu using apt-get ---

My impression is that recent versions of ubuntu come with openmpi
installed by default.

To see if you have openmpi installed, try running this command:
dpkg-query -s libopenmpi-dev

If so, then the following test should work. To test MPI, try
compiling the exampile mpi_hello.c program here and running it:
http://jetcracker.wordpress.com/2012/03/01/how-to-install-mpi-in-ubuntu/
(I assume you are trying to set up MPI on a single machine, not a cluster.)

If you do, but MPI is still not working, then perhaps you have
installed mpich2 in the past. In that case it may be clashing with
openmpi.

2) sudp apt-get remove mpich2
(That fixed the problems I was having)

If you do not have openmpi or mpich2 installed try either

sudo apt-get install libopenmpi-dev
or
sudo apt-get install mpich2

I hope this helps.

Andrew
If anybody has any corrections, please post them.

Andrew,

I think in case of openmpi, libopenmpi-dev will not be sufficient (it does not provide mpirun, for example). Similarly, mpich2 itself does not install headers and stuff like that. So you'll either need openmpi-bin + libopenmpi-dev (that is currently equal to install mpi-default-bin + mpi-default-dev) or mpich2 + libmpich2-dev.

Oleg.

30.10.2013, 19:16, "Andrew Jewett" <[email protected]>:

2) sudp apt-get remove mpich2
(That fixed the problems I was having)

correction:

sudo apt-get remove mpich2

Thank you!