Parallelism in programming

Divya Khatnar
3 min readFeb 9, 2023

Understand parallelism in plain English with examples

Credits: StockUp

Parallelism is a technique in computer programming that allows multiple tasks to run simultaneously. The goal of parallelism is to make a program run faster by dividing it into smaller, independent tasks that can be executed concurrently on different processors or cores.

Parallel programming can be achieved through several methods, including multi-threading, where multiple threads are created and executed in parallel, and multi-processing, where multiple processes are created and executed in parallel.

Parallelism can be used to solve complex problems more quickly and can be applied in a variety of domains, including scientific simulations, data processing, and gaming. However, parallel programming can be challenging due to the need to coordinate and synchronize the parallel tasks and manage shared resources, such as memory and I/O operations.

The most common use case for parallel programming is to improve the performance and scalability of a program. Parallel processing can be used to divide a task into smaller parts and run them concurrently, which can greatly reduce the time required to complete the task.

Some of the most common use cases for parallel programming include:

  1. Scientific simulations: Many scientific simulations, such as those used in physics, chemistry, and biology, can be computationally intensive and can take a long time to run. Parallel processing can be used to divide the simulation into smaller tasks and distribute them across multiple processors, resulting in faster and more accurate simulations.
  2. Data processing: Parallel processing can be used to divide large data processing tasks into smaller parts and run them concurrently, resulting in faster processing times and improved scalability.
  3. Gaming: Gaming applications can use parallel processing to improve the performance of graphics rendering and other tasks, resulting in a smoother and more immersive gaming experience.
  4. Machine learning: Machine learning algorithms can be computationally intensive, and parallel processing can be used to speed up the training process and reduce the time required to generate a model.
  5. Financial modeling: Parallel processing can be used to improve the performance of financial simulations, such as Monte Carlo simulations and portfolio optimization.

These are just a few examples of the most common use cases for parallel programming. The ability to divide a task into smaller parts and run them concurrently can greatly improve the performance and scalability of a system, making it an important technique for many types of applications.

Pseudo code for parallel programming in Python can vary depending on the parallel programming paradigm being used. Here is a general example of pseudo code for parallel programming in Python using the multiprocessing library:

import multiprocessing

def worker(task):
# Code to be executed in parallel

if __name__ == '__main__':
tasks = [...list of tasks to be executed in parallel...]
pool = multiprocessing.Pool(processes=4)
results = pool.map(worker, tasks)

In this example, the multiprocessing library is used to divide the list of tasks into separate processes and execute each process in parallel. The worker function contains the code that will be executed in parallel. The map function is used to apply the worker function to each task in the list. The processes argument is used to specify the number of processes to be used for the parallel execution.

Note that in Python, the if __name__ == '__main__': check is used to ensure that the code is executed only when the script is run as the main program and not when it is imported as a module. This is a common pattern used in multiprocessing in Python to prevent the child processes from executing the code in the parent process.

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