Inaccurate Logarithm in Python

Question

I work daily with Python 2.4 at my company. I used the versatile logarithm function \'log\' from the standard math library, and when I entered log(2**31, 2) it returned 31.0

Answer 1

floating-point operations are never exact. They return a result which has an acceptable relative error, for the language/hardware infrastructure.

In general, it's quite wrong to assume that floating-point operations are precise, especially with single-precision. "Accuracy problems" section from Wikipedia Floating point article :)