EuroPython 2011 Notes

By Michael Fötsch, on July 10th, 2011

These are some of my notes from EuroPython 2011. I mostly collect projects and tools that are of immediate interest to me in my own work. If you’re interested in the complete list of talks and would like to download the slides or watch the talks on video, you can find those on the EuroPython talks page. Also, Julie Pichon has summaries of some interesting talks on her site.

EuroPython Bag

Python Environment

At our company, we deploy non-interactive Python tools to our internal users. So far, we deploy these tools into the users’ local Python installations. Problems arise when the package versions that our tools require are different from the versions that the user has installed, or when updates to our tools require new dependencies to be installed. To avoid such problems, the “virtualenv” package allows you to keep separate Python environments for different tools. The “pip” package can then be used to automatically install dependencies into these environments. Alex Clemesha has an article up on his blog about the Tools of the Modern Python Hacker: Virtualenv, Fabric and Pip.

Another useful addition to the Python toolbox is the “nose” unit-testing package, which extends the Python “unittest” module. It has advanced support for test fixtures, generated test cases, running test batteries, and more. More at the “nose” project homepage.

. . . → Read More

Leave a comment   Python    

Continued Fractions for Representing Real Numbers

By Michael Fötsch, on July 9th, 2011

This is something I learned at EuroPython 2011. I think it came up in a lightning talk by Alex Martelli, but I don’t recall exactly.

Continued fractions are a representation of real numbers that allows for arbitrary-precision arithmetic.

If you’ve worked with floating-point numbers in Python (or most any other programming language, for that matter), you are aware of precision problems like this:

x = 1.0 / 3.0
total = 0.0
for i in range(300):
    total += x
print repr(total)
print total == 100.0

This prints 99.99999999999966, not 100.0. The reason is that the IEEE 754 floating-point representation of 1/3 isn’t exact, and this (initially small) error accumulates 300 times.

. . . → Read More

Leave a comment   Python    

My Buzz