org.deri.iris.rules.optimisation
Class ReplaceVariablesWithConstantsOptimiser

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

All Implemented Interfaces:

IRuleOptimiser

public class ReplaceVariablesWithConstantsOptimiser
extends Object
implements IRuleOptimiser

Replace variables with constants where possible: e.g. p(?X,?Y) :- q(?X, ?Z), ?Z = 't' ==>> p(?X,?Y) :- q(?X, 't') This should have the effect of pushing selection criteria in to the evaluation of a relation, such that fewer tuples are processed. Problem! p(?X), ?X = 2 is not the same as p(2), at least at the moment, because with p(2) the evaluator looks for only p( integer( 2 ) ) in the relation, whereas p(?X), ?X = 2 will return the entire relation and filter out what equals 2, i.e. any numeric value. Not sure how to fix this, but it will involve changing MixedDatatypeRelation.

Constructor Summary

ReplaceVariablesWithConstantsOptimiser()

Method Summary

IRule

optimise(IRule rule) Optimise the rule.

Methods inherited from class java.lang.Object

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

Constructor Detail

ReplaceVariablesWithConstantsOptimiser

public ReplaceVariablesWithConstantsOptimiser()

Method Detail

optimise

public IRule optimise(IRule rule)

Description copied from interface: IRuleOptimiser

Optimise the rule.

Specified by:

optimise in interface IRuleOptimiser

Parameters:

rule - The rule to optimise.

Returns:

The optimised rule.