Book Image

Python Parallel Programming Cookbook

By : Giancarlo Zaccone
Book Image

Python Parallel Programming Cookbook

By: Giancarlo Zaccone

Overview of this book

This book will teach you parallel programming techniques using examples in Python and will help you explore the many ways in which you can write code that allows more than one process to happen at once. Starting with introducing you to the world of parallel computing, it moves on to cover the fundamentals in Python. This is followed by exploring the thread-based parallelism model using the Python threading module by synchronizing threads and using locks, mutex, semaphores queues, GIL, and the thread pool. Next you will be taught about process-based parallelism where you will synchronize processes using message passing along with learning about the performance of MPI Python Modules. You will then go on to learn the asynchronous parallel programming model using the Python asyncio module along with handling exceptions. Moving on, you will discover distributed computing with Python, and learn how to install a broker, use Celery Python Module, and create a worker. You will understand anche Pycsp, the Scoop framework, and disk modules in Python. Further on, you will learnGPU programming withPython using the PyCUDA module along with evaluating performance limitations.
Table of Contents (13 chapters)
Python Parallel Programming Cookbook
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

How to use a process in a subclass


To implement a custom subclass and process, we must:

  • Define a new subclass of the Process class

  • Override the _init__(self [,args]) method to add additional arguments

  • Override the run(self [,args]) method to implement what Process should when it is started

Once you have created the new Process subclass, you can create an instance of it and then start by invoking the start() method, which will in turn call the run() method.

How to do it...

We will rewrite the first example in this manner:

#Using a process in a subclass Chapter 3: Process Based #Parallelism

import multiprocessing

class MyProcess(multiprocessing.Process):
    def run(self):
        print ('called run method in process: %s' %self.name)
        return

if __name__ == '__main__':
    jobs = []
    for i in range(5):
        p = MyProcess ()
        jobs.append(p)
        p.start()
        p.join()

To run the script from the Command Prompt, type the following command:

python subclass_process.py

The result...