org.deri.iris.rules.optimisation
Class ReOrderLiteralsOptimiser

java.lang.Object
  org.deri.iris.rules.optimisation.ReOrderLiteralsOptimiser

All Implemented Interfaces:

IRuleOptimiser

public class ReOrderLiteralsOptimiser
extends Object
implements IRuleOptimiser

Re-order literals. The RuleCompiler will be forced to re-order literals when it fails to set up the variable bindings between consecutive sub-goals. However, it might be possible to speed things up by selecting the most restrictive sub-goals (in the search sense) first. e.g. p(x,y) :- z!=x, x> p(x,y) :- q(x), r(y), x

Constructor Summary

ReOrderLiteralsOptimiser()

Method Summary

IRule

optimise(IRule rule) First version.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ReOrderLiteralsOptimiser

public ReOrderLiteralsOptimiser()

Method Detail

optimise

public IRule optimise(IRule rule)

First version. It works, but it is not very efficient. TODO Improve the whole thing to make it more elegant. This might interfere with magic sets, which orders sub-goals appropriately.

Specified by:

optimise in interface IRuleOptimiser

Parameters:

rule - The rule to optimise.

Returns:

The optimised rule.