Steps to configure, install and load Myricom's MPI implementation MPICH-GM.

1. Download the .gz file from
   http://www.myri.com:80/scs/index.html#downloads
   (direct link:
    ftp://comrade@ftp.myri.com/pub/MPICH-GM/mpich-1.2.1..7b.tar.gz)

2. Configure MPICH-GM to use ssh
   MPICH-GM uses either rsh (remote shell) or ssh (secure shell) to spawn off processes
   on remote nodes. The current setup assumes ssh version 2 is being used.
   The following steps need to be taken to configure MPI to use ssh.
   (Also see http://www-unix.mcs.anl.gov/mpi/mpich/docs/mphttp://www-unix.mcs.anl.gov/mpi/mpich/docs/mpichman-chp4/node46.htm#Node46ichman-chp4/node46.htm#Node46)
   - Create the authentication key.
     Type ssh-keygen -t rsa
     When prompted for a password type enter (i.e. do not set any password).
     This generates the public & private keys ~/.ssh/id_rsa.pub and ~/.ssh/id_rsa respectively.
   - Authorize acces. The above step is performed for all the nodes. The public keys of all
     the nodes are placed in the file ~/.ssh/authorized_keys2 by opening the .pub files, copying
     and pasting their contents into the file ~/.ssh/authorized_keys2.
   - This authorized_keys2 file is copied to all the nodes and placed in the directory ~/.ssh/
   - Configure MPICH-GM to use ssh by modifying the file mpich.make
     In mpich.make replace "setenv RSH rsh" by "setenv RSH ssh".

3. Configure MPICH-GM
   Type:
   setenv GM_HOME <location of directory where GM was installed>
   mpich.make

4. Create a conf file
   The "conf" file specifies the hosts on which the MPI application will
   run.  This file must be accessible on all the nodes where MPI processes
   will be running. Each process will read this conf file as will the mpirun
   script.
   This file has to be placed in ~/.gmpi/ and named "conf".
   The generic description of the contents of this file is:

   <num_nodes>
   <node_0_name> <node_0_port> [node_0_board_optional]
   <node_1_name> <node_1_port> [node_1_board_optional]
   <node_2_name> <node_2_port> [node_2_board_optional]
   .
   .
   .
   <node_N_name> <node_N_port> [node_N_board_optional]

   The ports here refer to the GM ports. These are 8 in number (0-7).
   Ports 2,4,5,6,7 are for users. Other ports are not for general user-process use.
   The 3rd parameter specifies the board number. This is of significance if a machine has
   multiple boards. Not specifying this parameter implies board 0. For the current setup it is not
   required to specify this parameter.
   The contents of the conf file for the current setup is as given below:
   4
   os16 2
   os15 2
   os14 2
   os13 2

5. Run test program

   Run the cpi program in examples/basic.
   Type:

   cd examples/basic
   make
   ../../bin/mpirun.ch_gm --gm-v cpi