What types of multitasking and parallelism are implemented in Python, and how are they applied?

Python implements several types of multitasking and parallelism:

1. Threads (Threading)

   • Allow multiple threads to run within a single process.
   • Due to GIL (Global Interpreter Lock), only one Python thread executes at a time in standard CPython, but threads are useful for I/O operations.

2. Multiprocessing

   • Creating multiple processes, each with its own memory.
   • Bypasses GIL limitations and allows code to run in parallel on multiple CPU cores.

3. Asynchronous programming (asyncio)

   • Enables writing non-blocking code using coroutines.
   • Efficient for a large number of I/O operations.

Application:

• Threads are suitable for I/O-intensive tasks.
• Multiprocessing is for CPU-intensive tasks.
• Asyncio for scalable network applications.

Example of using multiprocessing:

from multiprocessing import Pool

def f(x):
    return x*x

with Pool(4) as p:
    print(p.map(f, [1, 2, 3, 4]))