%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Basic Matlab MPI script that
% sends a matrix to another processor and also
% uses the MPI_Probe command.
%
% To run, start Matlab and type:
%
%   eval( MPI_Run('probe',2,{}) );
%
% Or, to run a different machine type:
%
%   eval( MPI_Run('probe',2,{'machine1' 'machine2'}) );
%
% Output will be piped into two files:
%
%   MatMPI/probe.0.out
%   MatMPI/probe.1.out
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% MatlabMPI
% Dr. Jeremy Kepner
% MIT Lincoln Laboratory
% kepner@ll.mit.edu
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% Initialize MPI.
MPI_Init;

% Create communicator.
comm = MPI_COMM_WORLD;

% Modify common directory from default for better performance.
% comm = MatMPI_Comm_dir(comm,'/tmp');

% Uncomment if you want to save the messages that were sent.
% comm = MatMPI_Save_messages(comm,1);

% Get size and rank.
comm_size = MPI_Comm_size(comm);
my_rank = MPI_Comm_rank(comm);

% Print rank.
disp(['my_rank: ',num2str(my_rank)]);

% Set who is source and who is destination.
source = 1;
dest = 0;

% Create a unique tag id for this message (very important in Matlab MPI!).
tag = 100045;

% Check to make sure that we have exactly two processors.
if(comm_size == 2)
  % Source.
  if (my_rank == source)
    % Create data.
    data = 1:10;
    % Send it.
    MPI_Send( dest, tag, comm, data, data );
  end
  % Destination.
  if (my_rank == dest)
    % Check to see if we have any mesages.
    keep_waiting = 1;
    while(keep_waiting)
      keep_waiting = keep_waiting + 1;
      disp(num2str(keep_waiting));
      [message_rank message_tag] = MPI_Probe( '*', '*', comm );
      pause(0.1);
      if (length(message_rank) > 0)
        keep_waiting = 0;
      end
    end

    % Receive data.
    [data data1] = MPI_Recv( source, tag, comm );
    % Check data.
    if(any((data  - (1:10)) ~= 0))
      disp('ERROR: incorrect data sent.');
      exit;
    end
  end
end

% Finalize Matlab MPI.
MPI_Finalize;
disp('SUCCESS');

% Don't exist if we are the host.
if (my_rank ~= MatMPI_Host_rank(comm))
  exit;
end


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Copyright 2002 Massachusetts Institute of Technology
% 
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