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Subject: Re: [OMPI users] More newbie question: LD_LIBRARY_PATH
From: Gus Correa (gus_at_[hidden])
Date: 2011-01-12 19:20:33


Tena Sakai wrote:
> Hi,
>
> On a FAQ page (
> http://www.open-mpi.org/faq/?category=running#adding-ompi-to-path),
> (under 1. What pre-requisites are necessary for running an Open MPI
> job?), I see an example
> of LD_LIBRARY_PATH environment variable:
> LD_LIBRARY_PATH: /opt/openmpi/lib
>
> When I compiled the source, a directory /usr/local/lib/openmpi was
> generated (with many
> files in it). Given that, do I set D_LIBRARY_PATH to /usr/local/lib or
> do I set
> it to /usr/local/lib/openmpi?
>
> Thank you.
>
> Tena Sakai
> tsakai_at_[hidden]
>

To /usr/local/lib.

I would suggest not using the default /usr/local to install OpenMPI,
since it tends to be really local to the machine where you built OpenMPI.
This will require that you install OpenMPI on all nodes/machines if
you want to run programs across a network.

Instead, a simpler way to get OpenMPI available to all nodes,
although installing only on one of them (say the head node of your
cluster) is to do it in a directory that is shared, typically via NFS.
To do so, use the --prefix=/my/shared/OpenMPI/directory option of
the configure script.

There are FAQs about this too.

Anyway, it may depend on your environment also, whether it is a cluster
with a private subnet (where my suggestion is typically used),
a bunch of separate computers on a LAN (where the suggestion won't work
unless you have a shared NFS directory), or other.

Gus Correa