Bugfix: Explicit import of rewards files for IMDPs.

Previously, when importing rewards, the evaluator was copied
from the model. But, currently, for interval models that does
not work, because the evaluator is for intervals.

Later, when uncertain models are refactored, copying from
models could likely be reinstated if prefered.

prism-tests/functionality/import/irobot.prism.importexport.auto

@@ -1 +1 @@
--importmodel irobot.all -exportmodel irobot.sta,tra,lab -ex
+-importmodel irobot.all -exportmodel irobot.all -ex

prism-tests/functionality/import/irobot.prism.orig

@@ -25,4 +25,4 @@ label "hazard" = s=1;
 label "goal1" = s=5;
 label "goal2" = s=2|s=3;
 
-//rewards "time" true : 1; endrewards
+rewards "time" true : 1; endrewards

prism-tests/functionality/import/irobot.srew

@@ -0,0 +1,9 @@
+# Reward structure "time"
+# State rewards
+6 6
+0 1
+1 1
+2 1
+3 1
+4 1
+5 1

prism-tests/functionality/import/irobot.trew

@@ -0,0 +1,3 @@
+# Reward structure "time"
+# Transition rewards
+6 10 0

prism/src/explicit/ExplicitFiles2Rewards.java

@@ -63,9 +63,19 @@ public class ExplicitFiles2Rewards<Value> extends PrismComponent implements Rewa
 	 * The rewards are actually imported/stored later, on demand.
 	 */
 	public ExplicitFiles2Rewards(PrismComponent parent, ExplicitModelImporter importer) throws PrismException
+	{
+		this(parent, importer, (Evaluator<Value>) Evaluator.forDouble());
+	}
+
+	/**
+	 * Construct a ExplicitFiles2Rewards object for a specified importer.
+	 * The rewards are actually imported/stored later, on demand.
+	 */
+	public ExplicitFiles2Rewards(PrismComponent parent, ExplicitModelImporter importer, Evaluator<Value> eval) throws PrismException
 	{
 		super(parent);
 		this.importer = importer;
+		this.eval = eval;
 		rewardInfo = importer.getRewardInfo();
 		// Initialise storage
 		rewards = new RewardsSimple[rewardInfo.getNumRewardStructs()];
@@ -74,12 +84,11 @@ public ExplicitFiles2Rewards(PrismComponent parent, ExplicitModelImporter import
 	/**
 	 * Provide access to the model for which the rewards are to be defined.
 	 * Needed to look up information when storing transition rewards.
-	 * The model's evaluator and attached states list is also stored.
+	 * The model's attached states list is also stored.
 	 */
 	public void setModel(Model<Value> model)
 	{
 		this.model = model;
-		eval = model.getEvaluator();
 		setStatesList(model.getStatesList());
 	}