1 Preliminaries

1.1 MPI on OS-systems LINIX, SOLARIS, AIX, etc.

The Message Passing Interface covers about 140 functions, available in F77, C and C++. Already 6 functions allow to write parallel codes. Most of the other functions are based on these 6. We will be concerned with the following functions.

Basic functions		MPI_Init
		MPI_Finalize
		MPI_Send
		MPI_Recv
		MPI_Comm_rank
		MPI_Comm_size
additional functions		MPI_Barrier
		MPI_Bcast
		MPI_Gather
		MPI_Scatter
		MPI_Reduce
		MPI_Allreduce

1.2 Online help

MPI Homepage	http://www.mcs.anl.gov/mpi/index.html
MPI Calls	http://www.mpi-forum.org/docs/mpi-11-html/mpi-report.html
LAM Implementierung	http://www.lam-mpi.org
with ftp-download	http://www.lam-mpi.org/download

1.3 Getting started on a pool of workstations

• Login at the Pool (computer myhost).
• Ensure that you can login from your machine at other ones by

  rlogin yourhost
  

  without being prompted for a passwd.
  If a password is required - enter it, edit/create file .rhosts

  vi ~/.rhosts
  

  by adding the line (here, foo names used)

           myhost  my_user_name
  

1.4 Installing the example code

Copy the files install and course.tar.gz into your working directory, and call ./install.

1.5 Getting started: LAM-MPI

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Define environmental variable archi (bash-shell) with one of the systems {LINUX, IRIX, SOLARIS, AIX}.

export archi=LINUX

or add it in your $(HOME)/.bashrc file. Check with env|grep archi .

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Initialize the LAM-MPI

lamboot

This lets you run several processes on your machine (or on a predefined set of machines) in parallel.

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If you have your own description file (like Example/mynode) of machines able to handle your code, then you could start MPI by

lamboot -v mynode

This lets you run several processes on your machine (or on a predefined set of machines) in parallel. If lamboot reports an error message then try lamboot -vd mynode to get a detailed report of the booting in progress.

1.6 Terminating LAM-MPI

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Kill all your MPI-processes which did not terminate regularly.

lamclean

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Terminate your MPI session

wipe