com.exigen.ie.constrainer.GoalFloatInstantiate Maven / Gradle / Ivy
package com.exigen.ie.constrainer;
///////////////////////////////////////////////////////////////////////////////
/*
* Copyright Exigen Group 1998, 1999, 2000
* 320 Amboy Ave., Metuchen, NJ, 08840, USA, www.exigengroup.com
*
* The copyright to the computer program(s) herein
* is the property of Exigen Group, USA. All rights reserved.
* The program(s) may be used and/or copied only with
* the written permission of Exigen Group
* or in accordance with the terms and conditions
* stipulated in the agreement/contract under which
* the program(s) have been supplied.
*/
///////////////////////////////////////////////////////////////////////////////
/**
* An implementation of a {@link Goal} that instaintiates the constraint floating-point variable.
*
* It recursively splits the domain of the variable into two parts.
* If the variable is already bound, it does nothing and succeeds. Otherwise, the goal
* sets a choice point, and replaces the domain by one of its halves, and calls itself again.
* The goal execution will be stopped when the variable is bound or when a failure occurs.
*
* @see FloatVar
*/
public class GoalFloatInstantiate extends GoalImpl
{
private FloatVar _var;
public GoalFloatInstantiate(FloatVar var)
{
super(var.constrainer(), "Instantiate("+var.name()+")");
_var = var;
}
/**
* An implementation of the dichotomize instantiation algorithm for the floating-point variable.
*/
public Goal execute() throws Failure
{
//Debug.on();Debug.print("Execute "+this+ " with " + _var);Debug.off();
if (_var.bound())
return null;
double mid_value = (_var.min()+_var.max())/2;
//Debug.on();Debug.print("Try "+mid_value);Debug.off();
Goal new_goal = new GoalOr(new GoalAnd(_var.lessOrEqual(mid_value),this),
new GoalAnd(_var.moreOrEqual(mid_value),this));
return new_goal;
}
}