# QuickLife

**QuickLife** is an algorithm used in Golly to efficiently and quickly run isotropic non-totalistic cellular automata. It was written from scratch, but originally inspired by both xlife and the algorithm used in Alan Hensel's Java-based Life applet.^{[note 1]}

QuickLife uses a tree structure to represent the universe, with each level increasing one of the dimensons by a factor of 8; this makes it possible to avoid using coordinates, and thus restricting the size of the universe. Distinct structures are used for 4×8, 32×8, and 32×32 sections of the universe; the sizes at the following levels are 256×32, 256×256, 2048×256, 2048×2048, etc. The tree contains both an even and odd generation, along with flags indicating if a subtree is stable, oscillating with period 2, or active. Details of the algorithm can be found in Golly's source code, specifically in the files `qlifealgo.h` and `qlifealgo.cpp`.

## Notes

- ↑ Cf. Alan Hensel's description for details on his applet.

## External links

- Quicklife Algorithm (discussion thread) at the ConwayLife.com forums
- Golly source code: