18.2.1 Prerequisites

You need to install this module first by executing the following in a terminal window:

conda install mpi4py

The module is imported by adding the following line to your Python script:

import mpi4py as mpi

The execution of a parallelized code is done from a terminal with the command mpiexec. Assuming that your code is stored in the file script.py, executing this code on a computer with a four-core CPU is done in the terminal window by running the following command:

mpiexec -n 4 python script.py

Alternatively, to execute the same script on a cluster with two computers, run the following in a terminal window:

mpiexec --hostfile=hosts.txt python script.py

You have to provide a file hosts.txt containing the names or IP addresses of the computers with the number of their cores you want to bind to a cluster:

# Content of hosts.txt
192.168.1.25 :4 # master computer with 4 cores
192.168.1.101:2 # worker computer with 2 cores

The Python script, here script.py, has to be copied...