package com.exigen.ie.constrainer.impl;
import com.exigen.ie.constrainer.Constrainer;
import com.exigen.ie.constrainer.Constraint;
import com.exigen.ie.constrainer.ConstraintImpl;
import com.exigen.ie.constrainer.EventOfInterest;
import com.exigen.ie.constrainer.Failure;
import com.exigen.ie.constrainer.Goal;
import com.exigen.ie.constrainer.GoalAnd;
import com.exigen.ie.constrainer.GoalGenerate;
import com.exigen.ie.constrainer.GoalPrint;
import com.exigen.ie.constrainer.GoalPrintObject;
import com.exigen.ie.constrainer.IntExp;
import com.exigen.ie.constrainer.IntExpArray;
import com.exigen.ie.constrainer.IntValueSelector;
import com.exigen.ie.constrainer.IntValueSelectorMin;
import com.exigen.ie.constrainer.IntVar;
import com.exigen.ie.constrainer.IntVarSelector;
import com.exigen.ie.constrainer.IntVarSelectorMinSize;
import com.exigen.ie.constrainer.Observer;
import com.exigen.ie.constrainer.Subject;
///////////////////////////////////////////////////////////////////////////////
/*
* 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 the constraint "All Different".
*
* Any two constrained integer expressions from the vector (parameter of this
* constraint) should can not be instantiated with the same value.
*/
public final class ConstraintAllDiff2 extends ConstraintImpl
{
// PRIVATE MEMBERS
private IntExpArray _intvars;
private IntVar _bit_var; // one bit for every possible values among all _intvars
//////////////////////////////////////////////// inner class AllDiffObserver
class AllDiffObserver extends Observer
{
public void update(Subject var, EventOfInterest interest)
throws Failure
{
IntExp event_var = (IntExp)var;
//Debug.on(); Debug.print("AllDiffObserver("+var+") "+interest+" "+_bits); Debug.off();
int value = event_var.value();
// check for failure
if (!_bit_var.contains(value))
{
//Debug.on();Debug.print("diff fail: "+interest+_intvars+_bits);Debug.off();
var.constrainer().fail("AllDiff"); //+_bits +" "+_intvars);
}
// set the bit
int size = _intvars.size();
_bit_var.removeValue(value); //Debug.on();Debug.print(" "+this+": "+_bits);Debug.off();
// additional propagation
for(int i=0; i<size; i++)
{
IntExp vari = (IntExp)_intvars.elementAt(i);
if (vari != event_var)
{
//Debug.on();Debug.print("alldiff remove "+value+" from "+vari);Debug.off();
vari.removeValue(value); // may fail
}
}
}
public int subscriberMask()
{
return EventOfInterest.VALUE;
}
public String toString()
{
return "AllDiff";//+_intvars;
}
public Object master()
{
return ConstraintAllDiff2.this;
}
} //~ AllDiffObserver
public ConstraintAllDiff2(IntExpArray intvars) throws Failure
{
super(intvars.constrainer(),"AllDiff");
_intvars = intvars;
int min = intvars.min();
int max = intvars.max();
_bit_var = constrainer().addIntVar(min,max + 1, IntVar.DOMAIN_BIT_FAST);
}
public Goal execute() throws Failure
{
// initial propagation
int size = _intvars.size();
boolean undo = false;
for(int i=0; i<size; i++)
{
IntExp vari = (IntExp)_intvars.elementAt(i);
if (vari.bound())
{
int value = vari.value();
boolean bit = _bit_var.contains(value);
// check for failure
if (!bit)
{
constrainer().fail("Diff");
}
_bit_var.removeValue(value);
}
}
// attach observers
Observer value_observer = new AllDiffObserver();
for(int i=0; i<size; i++)
{
IntExp vari = (IntExp)_intvars.elementAt(i);
vari.attachObserver(value_observer);
}
return null;
} // end of execute
// TEST
static void test1(String args[]) throws Exception
{
Constrainer C = new Constrainer("Test");
IntExp x = C.addIntVar(0,10,"x",IntVar.DOMAIN_DEFAULT);
IntExp y = C.addIntVar(2,10,"y",IntVar.DOMAIN_DEFAULT);
IntExp z = C.addIntVar(0,10,"z",IntVar.DOMAIN_DEFAULT);
int size = 3;
IntExpArray vars = new IntExpArray(C, size);
vars.set(x, 0);
vars.set(y, 1);
vars.set(z, 2);
Constraint constraintAllDiff2 = new ConstraintAllDiff2(vars);
constraintAllDiff2.execute();
//IntExp cost = C.addIntVar(0,20,"cost");
//Constraint sum = new ConstraintAddVector(vars,cost);
//sum.execute();
IntExp cost = C.sum(vars); cost.name("cost");
//x.lessOrEqual(y).execute();
x.mul(2).sub(cost).more(y).execute();
C.traceChoicePoints(vars);
//C.displayOnBacktrack(vars);
C.traceFailures(vars);
IntValueSelector value_selector = new IntValueSelectorMin();
IntVarSelector var_selector = new IntVarSelectorMinSize(vars);
Goal print = new GoalAnd(new GoalPrint(vars),new GoalPrintObject(C,cost));
Goal solution = new GoalAnd(print,
new GoalGenerate(vars,var_selector,value_selector),
print);
//if (!C.execute(new GoalMinimize(solution,cost)))
if (!C.execute(solution))
System.out.println("No solutions");
System.out.println(x + " " + y + " " + " " + z + cost);
}
} // ~ConstraintAllDiff2