Question

In random.py’s source code, there is the following constant definition:

BPF = 53        # Number of bits in a float
RECIP_BPF = 2**-BPF

I’m no math major, but isn’t it more readable to invert BPF by placing a 1 over it?

Or is there something about multiplication that is more convenient than division in programming?

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Nevermind.

In an effort to clean up my question I found this:

“On many machines, particularly those without hardware support for division, division is a slower operation than multiplication, so this approach can yield a considerable speedup. The first step is relatively slow but only needs to be done once.”

http://en.wikipedia.org/wiki/Multiplicative_inverse

Answer 1

Redability is subjective. That said, I personally find 2**-BPF easier to read than 1.0/2**BPF (with or without parentheses around 2**BFP).

As to performance differences, I doubt they are relevant since the expression is only evaluated once, when the module is imported.