Simulator complains about invalid (-ve/NaN) probs/rates.

git-svn-id: https://www.prismmodelchecker.org/svn/prism/prism/trunk@2184 bbc10eb1-c90d-0410-af57-cb519fbb1720

prism/src/prism/ModelType.java

@@ -53,6 +53,7 @@ public enum ModelType {
 	
 	/**
 	 * Do the transitions in a choice sum to 1 for this model type?
+	 * Can also use this to test whether models uses rates or probabilities.
 	 */
 	public boolean choicesSumToOne()
 	{

prism/src/simulator/Choice.java

@@ -45,4 +45,5 @@ public interface Choice
 	public State computeTarget(int i, State currentState) throws PrismLangException;
 	public void computeTarget(int i, State currentState, State newState) throws PrismLangException;
 	public int getIndexByProbabilitySum(double x);
+	public void checkValid(ModelType modelType) throws PrismException;
 }

prism/src/simulator/ChoiceList.java

@@ -30,6 +30,8 @@ import java.util.*;
 
 import parser.*;
 import parser.ast.*;
+import prism.ModelType;
+import prism.PrismException;
 import prism.PrismLangException;
 
 public class ChoiceList implements Choice
@@ -201,6 +203,12 @@ public class ChoiceList implements Choice
 		return i - 1;
 	}
 	
+	@Override
+	public void checkValid(ModelType modelType) throws PrismException
+	{
+		// TODO
+	}
+	
 	public String toString()
 	{
 		int i, n;

prism/src/simulator/ChoiceListFlexi.java

@@ -30,6 +30,8 @@ import java.util.*;
 
 import parser.*;
 import parser.ast.*;
+import prism.ModelType;
+import prism.PrismException;
 import prism.PrismLangException;
 
 public class ChoiceListFlexi implements Choice
@@ -284,6 +286,13 @@ public class ChoiceListFlexi implements Choice
 		return i - 1;
 	}
 
+	@Override
+	public void checkValid(ModelType modelType) throws PrismException
+	{
+		// Currently nothing to do here:
+		// Checks for bad probabilities/rates done earlier.
+	}
+	
 	public String toString()
 	{
 		int i, n;

prism/src/simulator/ChoiceSingleton.java

@@ -155,6 +155,12 @@ public class ChoiceSingleton implements Choice
 		return (i == 0) ? command : null;
 	}
 
+	@Override
+	public void checkValid(ModelType modelType) throws PrismException
+	{
+		// TODO
+	}
+	
 	@Override
 	public String toString()
 	{

prism/src/simulator/TransitionList.java

@@ -72,7 +72,18 @@ public class TransitionList
 		numTransitions += tr.size();
 		probSum += tr.getProbabilitySum();
 	}
-
+	
+	/**
+	 * Check the validity of the available transitions for a given model type.
+	 * Throw a PrismExecption if an error is found.
+	 */
+	public void checkValid(ModelType modelType) throws PrismException
+	{
+		for (Choice ch : choices) {
+			ch.checkValid(modelType);
+		}
+	}
+	
 	// ACCESSORS
 
 	/**

prism/src/simulator/Updater.java

@@ -191,7 +191,11 @@ public class Updater
 				transitionList.add(ch);
 			}
 		}
-
+		
+		// Check validity of the computed transitions
+		// (not needed currently)
+		//transitionList.checkValid(modelType);
+		
 		//System.out.println(transitionList);
 	}
 
@@ -272,7 +276,8 @@ public class Updater
 
 	/**
 	 * Create a new Choice object (currently ChoiceListFlexi) based on an Updates object
-	 * and a (global) state. If appropriate, check probabilities sum to 1 too.
+	 * and a (global) state. Check for negative probabilities/rates and, if appropriate,
+	 * check probabilities sum to 1 too.
 	 * @param moduleOrActionIndex Module/action for the choice, encoded as an integer (see Choice)
 	 * @param ups The Updates object 
 	 * @param state Global state
@@ -290,7 +295,16 @@ public class Updater
 		n = ups.getNumUpdates();
 		sum = 0;
 		for (i = 0; i < n; i++) {
+			// Compute probability/rate
 			p = ups.getProbabilityInState(i, state);
+			// Check for negative/NaN probabilities/rates
+			if (Double.isNaN(p) || p < 0) {
+				String s = modelType.choicesSumToOne() ? "Probability" : "Rate";
+				s += " is invalid (" + p + ") in state " + state.toString(modulesFile);
+				// Note: we indicate error in whole Updates object because the offending
+				// probability expression has probably been simplified from original form.
+				throw new PrismLangException(s, ups);
+			}
 			sum += p;
 			list = new ArrayList<Update>();
 			list.add(ups.getUpdate(i));