This is the second of my three-part look into symmetry reduction algorithms for speeding up grid-based pathfinding. In part one I introduced the notion of path symmetry: a property of uniform-cost grid maps which can significantly slow down optimal search. In this article I discuss Rectangular Symmetry Reduction (RSR for short): a new pre-processing algorithm […]| Shortest Path
In this article, the first in a three-part series, I attempt to explain path symmetry: a property of uniform-cost grid maps and other regular search domains which can significantly slow down pathfinding. I describe how symmetry manifests itself and briefly discuss some approaches that other people have tried to improve things. Finally, I introduce two […]| Shortest Path
Dungeons & Dragons started with slightly different rules for monsters and player characters. In the dungeon, doors that players left open always swung shut, but “doors will automatically open for monsters, unless they are held shut.” Mostly though, the same rules applied to heroes and monsters, a carryover from the game’s wargame roots. In the […]| DMDavid