Rulegolfing

Rulegolfing is an activity of constructing new rules or looking for variants of rules via successive incremental modifications to the rule definition, for example by adding or removing birth/survival conditions in the rulestring written using Hensel notation, or by changing lines in a rule table. Rulegolfing may involve multiple modifications of a rule, for example attempting to understand which changes make the rule explosive/chaotic, and trying to reach a rule with some desired properties. In general, any given "syntactic" change in the rule definition (such as adding a certain birth condition, or removing a certain survival condition, or adding/removing a line in a rule table) may have very different effects when the "syntactic" change is applied to different rules.

An example of a rule that was found via rulegolfing is the Langton's Ant simulator (B3-cjkq4knqy5cnr7/S02-cn3-ak4eiq5kq6e7e).

Existence of a well-recognised widespread notation to define rules from a given rulespace can be a powerful tool for rulegolfing, when the notation splits the rule definition into intuitively understandable parts that can be modified independently from each other.

Strategies for selecting 'interesting' rules from a large rulespace were discussed as early as 1994:

“ […] The real difficulty lies in *visualizing* what you are doing when you change values in the tables and drawing inferences about what values to change to produce what results. […] a strategy might be as follows. From randomized transition tables with random initial configurations, look for `interesting' small scale structures, such as gliders, blinkers, quasars, rotators, etc. Isolate these structures and analytically or experimentally determine their minimal transition tables, ie, the array of *necessary* transitions to produce the structure along with indications of the "Don't Care" transitions. Repeat until you have a decent library of these tables in a database. Now automate a search, compare and integrate process that will combine compatible transition tables. Investigate these new transition tables with random initial configurations. At a minimum, all compatible structures will be preserved and there will be the possibility of new, perhaps more complex structures. Isolate them and repeat the process until, at a limit, all "Don't Care" transitions are filled. This is more or less what I do, but I really haven't thought out the automated part of it. […] ” — Dr. Robert Andreen, Re: CA rules (04 Apr 94)

See also

• Tutorials/Finding rules
• Hybrid rule

External links

• Request a Rule to be "Tamed" (discussion thread) at the ConwayLife.com forums
• Rulegolfer script (discussion thread) at the ConwayLife.com forums -- a Python script based on qfind for finding spaceship-friendly rules
• Re: Golly scripts (discussion thread) at the ConwayLife.com forums -- an automated rulegolfing script for 2-state INT rules