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Getting started

Logging In

Users can log into Euclid using the Secure Shell (SSH) protocol 2 with the following command:

% ssh -l username euclid.nersc.gov

When you successfully log in you will land in your $HOME directory.

Euclid is a one node system. All jobs that run on Euclid, e.g. compiles, edits, user jobs, etc,. run on the same node.

Sample Program Code: Parallel Hello World

Although Euclid was not intended for production runs of MPI codes, it is possible to run small MPI codes on it.

Open a new file called helloWorld.f90 with a text editor such as emacs or vi. Paste the contents of the below code into the file.

program helloWorld

implicit none

include "mpif.h"

integer :: myPE, numProcs, ierr

call MPI_INIT(ierr)

call MPI_COMM_RANK(MPI_COMM_WORLD, myPE, ierr)

call MPI_COMM_SIZE(MPI_COMM_WORLD, numProcs, ierr)

print *, "Hello World from ", myPE

call MPI_FINALIZE(ierr)

end program helloWorld

Compiling the Program

% mpif90 -o helloWorld helloWorld.f90

Running the Job

Euclid does not have a batch system.  All jobs are truly interactive and all run on the single 48 core node, sharing it with all other interactive users and all other processes.

To launch the job with 8 MPI processes, use the mpirun job launcher on the command line:

% mpirun -np 8 ./helloWorld

The job will start running instantaneously and will display this output to the screen when it is completed:

Hello World from             2
Hello World from             3
Hello World from             1
Hello World from             0
Hello World from             6
Hello World from             5
Hello World from             7
Hello World from             4