In the past, I’ve worked with a rules engine for Java cutely named “Drools”. It’s complicated but it can very efficiently compute changes to huge systems of interrelated variables. Out of curiosity, I searched to see if anyone had ported it to Android — it seemed unlikely because it compiles down to bytecode at runtime.
What did my Google seach for “android drools” reveal? A blog titled “Android rules, iPhone drools”. Sigh.