Mastering IPython 4.0

MPI

The Message Passing Interface (MPI) is a language-independent message passing library standard. It has been implemented in several languages, including Fortran, C/C++, and Python. This book will use the Mpi4py implementation. Chapter 3, Stepping Up to IPython for Parallel Computing, outlined the process for starting IPython using MPI. It will be assumed that IPython has been started this way in the following examples.

Hello World

Here is the MPI "Hello world" program. It has every process reply with a simple string, along with the rank of the process:

from mpi4py import MPI
comm = MPI.COMM_WORLD
rank = comm.Get_rank()
print("hello world from process ", rank)

• Line 2: This obtains a communicator object. A communicator is a logical structure that ...