MPI_STUBS
Dummy MPI Library

MPI_STUBS is a C++ library which implements "stub" MPI routines.

MPI_STUBS is intended to include stubs for the most commonly called MPI routines. Most of the stub routines don't do anything. In a few cases, where it makes sense, they do some simple action or return a value that is appropriate for the serial processing case.

MPI_STUBS can be used as a convenience, when a real MPI implementation is not available, and the user simply wants to test-compile a code. It may also be useful in those occasions when a code has been so carefully written that it will still execute correctly on a single processor.

MPI_STUBS is based on a similar package supplied as part of the LAMMPS program, which allow that program to be compiled, linked and run on a single processor machine, although it is normally intended for parallel execution.

This C++ implementation is very sketchy. I am struggling to implement it in a way that includes an MPI namespace.

Licensing:

The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.

Related Data and Programs:

LAMMPS is a FORTRAN77 molecular dynamics simulation program which uses MPI. A serial version can be created by linking the program with the MPI_STUBS library.

MPI is an library of message passing routines which enables parallel processing on a variety of machine architectures, and with a varying number of processors.

MPI_INTRODUCTION is a one page introduction to MPI.

MPI_MORE_INFO contains a list of references, web sites, examples and tutorials on MPI.

MPI_STUBS is available in a C version and a C++ version and a FORTRAN77 version and a FORTRAN90 version.

PETSC is a directory of FORTRAN77 programs which illustrate the use of the PETSC scientific programming library for parallel programming, which requires MPI in order to run.

PLTMG_SINGLE is a FORTRAN77 program which carries out the finite element method, and can be compiled and run with the MPI library.

Reference:

1. William Gropp, Ewing Lusk, Anthony Skjellum,
   Using MPI: Portable Parallel Programming with the Message-Passing Interface,
   Second Edition,
   MIT Press, 1999,
   ISBN: 0262571323,
   LC: QA76.642.G76.

Source Code:

• mpi_stubs.C, the source code.
• mpi_stubs.H, the include file.
• mpi_stubs.csh, commands to compile the source code.

Examples and Tests:

HELLO is a simple program that says "Hello, world!".

• hello.C, a sample calling program.
• hello.csh, commands to compile and run the sample program.
• hello_output.txt, the output file.

List of Routines:

• MPI_ALLGATHER gathers data from all the processes in a communicator.
• MPI_ALLGATHERV gathers data from all the processes in a communicator.
• MPI_ALLREDUCE carries out a reduction operation.
• MPI_BARRIER forces processes within a communicator to wait together.
• MPI_BCAST broadcasts data from one process to all others.
• MPI_CART_CREATE creates a communicator for a Cartesian topology.
• MPI_CART_GET returns the "Cartesian coordinates" of the calling process.
• MPI_CART_SHIFT finds the destination and source for Cartesian shifts.
• MPI_COMM_DUP duplicates a communicator.
• MPI_COMM_FREE frees a communicator.
• MPI_COMM_RANK reports the rank of the calling process.
• MPI_COMM_SIZE reports the number of processes in a communicator.
• MPI_COMM_SPLIT splits up a communicator based on a key.
• MPI_COPY_BYTE copies a byte vector.
• MPI_COPY_DOUBLE copies a double vector.
• MPI_COPY_FLOAT copies a float vector.
• MPI_COPY_INT copies an int vector.
• MPI_FINALIZE shuts down the MPI library.
• MPI_GET_COUNT reports the actual number of items transmitted.
• MPI_INIT initializes the MPI library.
• PI_IRECV receives data from another process.
• MPI_RECV receives data from another process within a communicator.
• MPI_REDUCE carries out a reduction operation.
• MPI_REDUCE_DOUBLE carries out a reduction operation on doubles.
• MPI_REDUCE_FLOAT carries out a reduction operation on floats.
• MPI_REDUCE_INT carries out a reduction operation on ints.
• MPI_REDUCE_SCATTER collects a message of the same length from each process.
• MPI_RSEND "ready sends" data from one process to another.
• MPI_SEND sends data from one process to another.
• MPI_WAIT waits for an I/O request to complete.
• MPI_WAITALL waits until all I/O requests have completed.
• MPI_WAITANY waits until one I/O requests has completed.
• MPI_WTIME returns the elapsed wall clock time.
• TIMESTAMP prints the current YMDHMS date as a time stamp.

You can go up one level to the C++ source codes.