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//==============================================================================
//
// Copyright (c) 2002-
// Authors:
// * Dave Parker <d.a.parker@cs.bham.ac.uk> (University of Birmingham/Oxford)
// * Mateusz Ujma <mateusz.ujma@cs.ox.ac.uk> (University of Oxford)
//
//------------------------------------------------------------------------------
//
// This file is part of PRISM.
//
// PRISM is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// PRISM is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with PRISM; if not, write to the Free Software Foundation,
// Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
//
//==============================================================================
package explicit;
import java.util.ArrayList;
import java.util.BitSet;
import java.util.List;
import explicit.SCCComputer.SCCMethod;
/**
* Maximal end component computer for a nondeterministic model such as MDP.
*/
public class ECComputerDefault extends ECComputer
{
/* The model to compute (M)ECs for */
private NondetModel model;
/* Computed list of MECs */
private List<BitSet> mecs = new ArrayList<BitSet>();
/**
* Build (M)EC computer for a given model.
*/
public ECComputerDefault(NondetModel model)
{
this.model = model;
}
// Methods for SCCComputer interface
@Override
public void computeMECs()
{
SCCComputer sccc = SCCComputer.createSCCComputer(SCCMethod.TARJAN, model);
sccc.computeSCCs();
List<BitSet> sccs = sccc.getSCCs();
for(int i=0;i<sccs.size();i++) {
if(isMEC(sccs.get(i))) {
System.out.println("SCCs " + sccs.get(i));
mecs.add(sccs.get(i));
}
}
}
@Override
public List<BitSet> getMECs()
{
return mecs;
}
private boolean isMEC(BitSet b) {
if(b.cardinality() == 0) return false;
int state = b.nextSetBit(0);
while(state != -1) {
boolean atLeastOneAction = false;
for(int i=0;i<model.getNumChoices(state);i++) {
if(model.allSuccessorsInSet(state, i, b)) {
atLeastOneAction = true;
}
}
if(!atLeastOneAction) {
return false;
}
state = b.nextSetBit(state+1);
}
return true;
}
}