May 30 – 31, 2016
CERN
Europe/Zurich timezone
There is a live webcast for this event.

Writing faster Python

May 31, 2016, 5:00 PM
30m
31/3-004 - IT Amphitheatre (CERN)

31/3-004 - IT Amphitheatre

CERN

105
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Speaker

Sebastian Witowski (CERN)

Description

Did you know that Python preallocates integers from -5 to 257 ? Reusing them 1000 times, instead of allocating memory for a bigger integer, can save you a couple of milliseconds of code’s execution time. If you want to learn more about this kind of optimizations then, … well, probably this presentation is not for you :) Instead of going into such small details, I will talk about more "sane" ideas for writing faster code. After a very brief overview of how to optimize Python code (rule 1: don’t do this; rule 2: don’t do this yet; rule 3: ok, but what if I really want to do this ?), I will show simple and fast ways of measuring the execution time and finally, discuss examples of how some code structures could be improved. You will see:

  • What is the fastest way of removing duplicates from a list
  • How much faster your code is when you reuse the built-in functions instead of trying to reinvent the wheel
  • What is faster than the good ol’ for loop
  • If the lookup is faster in a list or a set (and when it makes sense to use each)
  • How the “It’s better to beg for forgiveness than to ask for permission” rule works in practice

I will NOT go into details of "serious" optimization, like using different Python implementation or rewriting critical code in C, etc.

Talk Length 30 minutes

Author

Sebastian Witowski (CERN)

Presentation materials