This project refer to the chapter 3 in An Introduction to Parallel Programming book by Peter Pacheco.

Installing MPI package:

$ ./install_mpi

During MPI_Init, all of MPI's global and internal variables are constructed. For example, a communicator is formed around all of the processes that were spawned, and unique ranks are assigned to each process. Currently, MPI_Init takes two arguments that are not necessary, and the extra parameters are simply left as extra space in case future implementations might need them.

MPI_Init example:

MPI_Init(
    int* argc,
    char*** argv)

MPI_Comm_size returns the size of a communicator.

MPI_Comm_size example:

MPI_Comm_size(
    MPI_Comm communicator,
    int* size)

MPI_Comm_rank returns the rank of a process in a communicator. Each process inside of a communicator is assigned an incremental rank starting from zero. The ranks of the processes are primarily used for identification purposes when sending and receiving messages.

MPI_Comm_rank example:

MPI_Comm_rank(
    MPI_Comm communicator,
    int* rank)

MPI_COMM_WORLD (which is constructed for us by MPI) encloses all of the processes in the job, so this call should return the amount of processes that were requested for the job.

MPI_Get_processor_name obtains the actual name of the processor on which the process is executing.

MPI_Comm_rank example:

MPI_Get_processor_name(
    char* name,
    int* name_length)

MPI_Finalize is used to clean up the MPI environment. No more MPI calls can be made after this one.

MPI_Finalize()

To compile this prjoect:

$ make all

To clean compilation project:

$ make clean

To run the project and set the number of processes:

$ ./exec

To run the project in multiple nodes and set the number of processes. You must follow this step first, to setup the NFS and synchronize all the nodes.

• Copy executable file (ex: hello_word) to nfs directory (ex: cloud) to sync with all nodes:

    $ cp hello_word ~/cloud
    $ ./exec-multi hello_word
  

then the response in the number of processes or MPI_Comm_size.

• Process = world_rank
• Location = world_size

Ignore this, this section only common knowledge about what i've found when search this topic.

• OpenMPI vs Mpich.
• MPI (Parallel Computing) and AMQP (Distributed Computing).
• Analyze your needs.