Hummus and Magnets personal blog
Understanding the math behind 0x5f3759df and the fast inverse square root (2012)
This post is about the magic constant 0x5f3759df and an extremely neat hack, fast inverse square root, which is where the constant comes from.
- Points
- 222
- HN comments
- 44
- Submissions
- 2
- Cited by
- 4 commenters
Math & AlgorithmsSoftware Engineering2017
On Hacker News
| Submitted | Title on HN | Points | Comments |
|---|---|---|---|
| Aug 16, 2017 | Understanding the math behind 0x5f3759df and the fast inverse square root (2012) by ColinWright | 222 | 19 |
| Oct 28, 2014 | 0x5f3759df and the fast inverse square root (2012) by carljoseph | 125 | 25 |
Cited in comments
Linked from 4 Hacker News comments by 4 different people, from Dec 2015 to Aug 2025.
Most recent:
- nwallin · Aug 24, 2025
- Greek0 · Nov 2, 2020
- forgotpwtomain · Mar 9, 2016
- timdierks · Dec 22, 2015
