function [defscommands, unix_command] = ...
  MatMPI_Commands(m_file,rank,MPI_COMM_WORLD)
% MatMPI_Commands  -  Commands to launch a matlab script remotely.
%
%  [defscommands, unix_command] = ...
%    MatMPI_Commands(m_file,rank,MPI_COMM_WORLD)
%

  % Set newline string.
  nl = sprintf('\n');

  % Create filename each Matlab job will run at startup.
  defsbase = ['MatMPI/defs' num2str(rank)];
  defsfile = [defsbase '.m'];
  comm_mat_file = 'MatMPI/MPI_COMM_WORLD.mat';
  outfile = ['MatMPI/' m_file '.' num2str(rank) '.out'];

  % Get single quote character.
  q = strrep(' '' ',' ','');

  % Create Matlab MPI setup commands.
  commands{1} = ['global MPI_COMM_WORLD;' nl];
  commands{2} = ['load ' q comm_mat_file q ';' nl];
  commands{3} = ['MPI_COMM_WORLD.rank = ' num2str(rank) ';' nl];
  commands{4} = ['delete(' q defsfile q ');' nl];
  commands{5} = [m_file ';' nl];

  defscommands = '';

  % Get name of host.
  machine_id = MPI_COMM_WORLD.machine_id(1,rank+1);
  machine = MPI_COMM_WORLD.machine_db.machine{1,machine_id};
  remote_launch = MPI_COMM_WORLD.machine_db.remote_launch{1,machine_id};
  remote_flags = MPI_COMM_WORLD.machine_db.remote_flags{1,machine_id};
  matlab_command = MPI_COMM_WORLD.machine_db.matlab_command{1,machine_id};

  % Print name of machine we are launching on.
  disp(['Launching MPI rank: ' num2str(rank) ' on: ' machine]);

  % Create base matlab command.
  matlab_command = [matlab_command ' < ' defsfile ' > ' outfile ];
  % matlab_command = [matlab_command ' -r ' defsfile ' -logfile ' outfile ' > /def/null'];
  % matlab_command = [matlab_command ' -r ' defsfile ' -logfile ' outfile ];
  % matlab_command = [matlab_command ' -r ' defsfile ' > ' outfile ];

  % Determine how to run script and where to send output.
  host = getenv('HOST');
  if (strcmp(machine,host))
    if (rank == 0)
      % Run defsfile scipt interactively.
      defscommands = [commands{1} commands{2} commands{3} commands{5}];
      unix_command = nl;
    else
      % Write commands to a .m text file.
      fid = fopen(defsfile,'wt');
      n_command = size(commands,2);
      for i_command=1:n_command
        fwrite(fid,commands{i_command});
      end
      fclose(fid);

      % Create command to run defsfile locally and pipe output to another file.
      unix_command = [matlab_command ' &' nl 'touch MatMPI/pid.' machine '.$!' nl];
    end
  else

    % Write commands to a .m text file.
    fid = fopen(defsfile,'wt');
    n_command = size(commands,2);
    for i_command=1:n_command
      fwrite(fid,commands{i_command});
    end
    fclose(fid);

    % Create command to run defsfile locally and pipe output to another file.
    unix_command = [matlab_command ' &' nl 'touch MatMPI/pid.' machine '.$!' nl];

  end

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% MatlabMPI
% Dr. Jeremy Kepner
% MIT Lincoln Laboratory
% kepner@ll.mit.edu
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Copyright 2002 Massachusetts Institute of Technology
% 
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%
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% THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF MIT HAS BEEN ADVISED OF THE
% POSSIBILITY OF SUCH DAMAGE.
% 
% MIT SPECIFICALLY DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTIES INCLUDING,
% BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS
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%
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