Deadlocks and permutations for explicit.

git-svn-id: https://www.prismmodelchecker.org/svn/prism/prism/trunk@1852 bbc10eb1-c90d-0410-af57-cb519fbb1720

prism/src/explicit/DTMCEmbeddedSimple.java

@@ -128,6 +128,12 @@ public class DTMCEmbeddedSimple implements DTMC
 		// No deadlocks by definition
 	}
 
+	public BitSet findDeadlocks(boolean fix) throws PrismException
+	{
+		// No deadlocks by definition
+		return new BitSet();
+	}
+
 	public void exportToPrismExplicit(String baseFilename) throws PrismException
 	{
 		throw new PrismException("Export not yet supported");

prism/src/explicit/DTMCSimple.java

@@ -301,6 +301,23 @@ public class DTMCSimple extends ModelSimple implements DTMC
 		}
 	}
 
+	@Override
+	public BitSet findDeadlocks(boolean fix) throws PrismException
+	{
+		int i;
+		BitSet deadlocks = new BitSet();
+		for (i = 0; i < numStates; i++) {
+			if (trans.get(i).isEmpty())
+				deadlocks.set(i);
+		}
+		if (fix) {
+			for (i = deadlocks.nextSetBit(0); i >= 0; i = deadlocks.nextSetBit(i + 1)) {
+				setProbability(i, i, 1.0);		
+			}
+		}
+		return deadlocks;
+	}
+
 	@Override
 	public void exportToPrismExplicit(String baseFilename) throws PrismException
 	{

prism/src/explicit/DTMCUniformisedSimple.java

@@ -139,6 +139,12 @@ public class DTMCUniformisedSimple implements DTMC
 		// No deadlocks by definition
 	}
 
+	public BitSet findDeadlocks(boolean fix) throws PrismException
+	{
+		// No deadlocks by definition
+		return new BitSet();
+	}
+
 	public void exportToPrismExplicit(String baseFilename) throws PrismException
 	{
 		throw new PrismException("Export not yet supported");

prism/src/explicit/MDPSimple.java

@@ -110,6 +110,26 @@ public class MDPSimple extends ModelSimple implements MDP
 		// TODO: copy rewards, etc.
 	}
 
+	/**
+	 * Construct an MDP from an existing one and a state index permutation,
+	 * i.e. in which state index i becomes index permut[i].
+	 * Note: have to build new Distributions from scratch anyway to do this,
+	 * so may as well provide this functionality as a constructor.
+	 */
+	public MDPSimple(MDPSimple mdp, int permut[])
+	{
+		this(mdp.numStates);
+		for (int in : mdp.getInitialStates()) {
+			addInitialState(permut[in]);
+		}
+		for (int i = 0; i < numStates; i++) {
+			for (Distribution distr : mdp.trans.get(i)) {
+				addChoice(permut[i], new Distribution(distr, permut));
+			}
+		}
+		// TODO: permute rewards
+	}
+
 	// Mutators (for ModelSimple)
 
 	@Override
@@ -398,6 +418,26 @@ public class MDPSimple extends ModelSimple implements MDP
 		// TODO: Check for empty distributions too?
 	}
 
+	@Override
+	public BitSet findDeadlocks(boolean fix) throws PrismException
+	{
+		int i;
+		BitSet deadlocks = new BitSet();
+		for (i = 0; i < numStates; i++) {
+			// Note that no distributions is a deadlock, not an empty distribution
+			if (trans.get(i).isEmpty())
+				deadlocks.set(i);
+		}
+		if (fix) {
+			for (i = deadlocks.nextSetBit(0); i >= 0; i = deadlocks.nextSetBit(i + 1)) {
+				Distribution distr = new Distribution();
+				distr.add(i, 1.0);
+				addChoice(i, distr);
+			}
+		}
+		return deadlocks;
+	}
+
 	@Override
 	public void exportToPrismExplicitTra(String filename) throws PrismException
 	{

prism/src/explicit/Model.java

@@ -104,6 +104,12 @@ public interface Model
 	 */
 	public void checkForDeadlocks() throws PrismException;
 
+	/**
+	 * Find all deadlocks and return a BitSet of these states.
+	 * If requested (if fix=true, then add self-loops in these states).
+	 */
+	public BitSet findDeadlocks(boolean fix) throws PrismException;
+
 	/**
 	 * Checks for deadlocks and throws an exception if any exist.
 	 * States in 'except' (If non-null) are excluded from the check.

prism/src/explicit/STPG.java

@@ -366,6 +366,28 @@ public class STPG extends ModelSimple
 		// TODO: Check for empty distributions sets too?
 	}
 
+	@Override
+	public BitSet findDeadlocks(boolean fix) throws PrismException
+	{
+		int i;
+		BitSet deadlocks = new BitSet();
+		for (i = 0; i < numStates; i++) {
+			// Note that no distributions is a deadlock, not an empty distribution
+			if (trans.get(i).isEmpty())
+				deadlocks.set(i);
+		}
+		if (fix) {
+			for (i = deadlocks.nextSetBit(0); i >= 0; i = deadlocks.nextSetBit(i + 1)) {
+				DistributionSet distrs = newDistributionSet(null);
+				Distribution distr = new Distribution();
+				distr.add(i, 1.0);
+				distrs.add(distr);
+				addDistributionSet(i, distrs);
+			}
+		}
+		return deadlocks;
+	}
+
 	/**
 	 * Build (anew) from a list of transitions exported explicitly by PRISM (i.e. a .tra file).
 	 */