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Exploring parallel programming

When I first started blogging, I have a lot of geeky posting about software development. The idea of blogging is to write on short subjects frequently. It is different from writing a long article, which is so burdensome many people end up not doing it at all. But in practice, I have not lived up to expectation of a prolific blogger. Sometimes the gap between postings can be a few months.

Anyway this is the quick posting on geeky subject that I think I should do more. Recently I am working on high performance computing and number crunching task. I have dipped into writing C extension for Python for performance. I got spectacular result from the exercise. It is the best of both world. Programming in Python supplement by C is still very agile and iterative. On the other hand C is giving the performance unachievable with pure Python.

I am started to look into the multiprocessing module introduced in Python 2.6. It is a library to run multiple python processes. With an interface similar to the threading module, it is positioning itself as an alternative approach to threading to circumvent the limitation of Python's GIL. I haven't give much thought to it initially. But looking closer, I find it is really more than just an alternative to threading. It is really a parallel programming framework. For example, the method Pool.map() is really a prototype of a mapreduce framework. I am quite excited to explore this module in the coming days.

Another module I am looking at is the ctypes module. It allows Python code to call C functions directly. Again I haven't thought much about it when it was introduced in Python 2.5. That's because I haven't have a use case of it. Now that I am writing C module, I begin to realize how revolutionary it is. C module delivery great performance. But writing one is a pain. Just the need to keep track of reference count may double the number of lines of your code. For me I am not building a reusable module for other people. It is one off function for me to do number crunching. Using ctypes may allow me easier access to C without the burden of actually writing a Python module.

2009.07.12 [, ] - comments

 

 

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