Lua vs Python

By Michael Doornbos

January 17, 2025 - 2 minutes read - 358 words

123

Introduction

Unscientific Benchmarks

Don’t get too twisted up about how scientific these are. I’m looking to do a rough comparison of some common tasks here.

I initially just did a simple addition.

Add all of the numbers from 1 to n.

Then I started to think about the fact that maybe the Lua startup time was a big factor in my numbers so I made it longer and configurable, with a way to keep track of a number of runs and give me a percentage difference.

time python run_sum_benchmark.py -n 50000000 -t 5

Yes, you can more easily sum natural numbers…

This formula comes from the mathematical definition of the sum of the first $n$ natural numbers:

()\text{Sum} = 1 + 2 + 3 + \dots + n = \frac{n \cdot (n + 1)}{2}()

This formula is derived from the observation that pairing numbers from opposite ends of the series (e.g., $ 1 + n, 2 + (n-1), \dots $) results in $n/2$ pairs of equal sums, each being $ n+1 $. Multiplying the number of pairs ($ n/2 $) by the value of each pair ($ n+1 $) gives the total sum.

The // 2 in Python’s implementation ensures that the division is performed as integer division, avoiding fractional results that are irrelevant since the sum of natural numbers is always an integer.

In simpler terms:

Multiplication first calculates $ n \cdot (n+1) $.
Division by 2 adjusts for the pairing logic inherent in the formula.

For $ n = 500,000,000 $, this avoids iterating through all numbers individually, significantly speeding up the calculation.

Twelve

x times faster vs percent

When our benchmark says “Language A was $p\%$ faster than Language B”, we can convert this to a multiplier:

$%$ \text{Multiplier} = \frac{p + 100}{100} $ For example, with 417.4%: $ \text{Multiplier} = \frac{417.4 + 100}{100} = \frac{517.4}{100} = 5.174 $%$

So you’re saying it’s 5.174 times faster…

Conversely, to get the percentage from a multiplier $m$:

$%$ p = (m - 1) \times 100 $ For example, with multiplier 5.174: $ p = (5.174 - 1) \times 100 = 4.174 \times 100 = 417.4\% $%$