[CPMD-list] linux cl;usters

[Per Andersson]

Zak wrote:
> Dear group,
> 
> I am considering compiling CPMD for a two node linux cluster I have no
> experience of parallel computing ,infact i have little experience with
> computing par se. With help i have recently compiled for PC-IFC. 
> 
> The question I am asking is this a realistic aspiration ?
> 
> any thoughts from anyone would be extremely helpful.
> 
> Thank you all in advance for your replies,
> 
> 
> Zak
> 

It is not that difficult to install CPMD to run on
a cluster but depending on the interconnect between
the nodes it is not always so efficient. The long
latency and the low bandwidth makes fast ethernet
slow and you loose both cpu time and in some cases
even wall-clock time. If you are running out of memory
it is sometimes better to buy more memory and run
two separate jobs instead.

If you still want to do it: install mpi on the nodes.
I always use MPICH from Argonne but
http://www.netlib.org/mpi/index.html is a good start.
If you read the documentation on how to install the
mpi of your choice it is not too difficult. Configure
rsh/ssh according to the documentation and set the
right configure-options for you machine (linux, no
shared memory, which gcc/f77/f90), make and make install.
The default is
to put the mpi-libraries in /usr/local and I hope
that the LINUX-IFC-MPI for CPMD is pointing there.
The important thing to look for in the CPMD makefile
is that the compiler (FC) is set to /whereever_you_put_it/mpif77.
If CPMD compiles, start your jobs with mpirun. All files
must be on a disk read/write-able from both nodes.

/Per Andersson