introduce prism.Product wrapper for the result of a product construction (similar to explicit.Product)

git-svn-id: https://www.prismmodelchecker.org/svn/prism/prism/trunk@12051 bbc10eb1-c90d-0410-af57-cb519fbb1720

prism/src/prism/Product.java

@@ -0,0 +1,102 @@
+package prism;
+
+import jdd.JDD;
+import jdd.JDDNode;
+import jdd.JDDVars;
+import prism.PrismException;
+
+/**
+ * Base class for the results of a product operation between a symbolic model and
+ * an automaton. Provides infrastructure for converting information on the
+ * states between the original model, the automaton and the product model.
+ *
+ * @param <M> The type of the product model, e.g, DTMC, MDP, ...
+ */
+public class Product<M extends Model> implements ModelTransformation<M, M>
+{
+	protected M originalModel = null;
+	protected M productModel = null;
+	protected JDDNode productStatesOfInterest = null;
+	protected JDDVars automatonRowVars = null;
+
+	/**
+	 * Constructor.
+	 * <br>
+	 * Takes ownership of productModel, productStatesOfInterest and automatonRowVars,
+	 * clears those when clear() is called.
+	 * <br>[ STORES: productModel, productStatesOfInterest, automatonRowVars ]
+ 	 * @param productModel the product model
+ 	 * @param originalModel the original model
+ 	 * @param productStatesOfInterest the statesOfInterest in the product (starting points of the product construction)
+ 	 * @param automatonRowVars the DD row vars of the automaton
+	 */
+	public Product(M productModel, M originalModel, JDDNode productStatesOfInterest, JDDVars automatonRowVars) {
+		this.originalModel = originalModel;
+		this.productModel = productModel;
+		this.productStatesOfInterest = productStatesOfInterest;
+		this.automatonRowVars = automatonRowVars;
+	}
+
+	/**
+	 * Get the product model (not a copy).
+	 */
+	public M getProductModel()
+	{
+		return productModel;
+	}
+
+	@Override
+	public M getTransformedModel()
+	{
+		return getProductModel();
+	}
+
+	@Override
+	public M getOriginalModel()
+	{
+		return originalModel;
+	}
+
+	/**
+	 * Provides access to the row variables of the automaton part of the product.
+	 * <br>[ REFS: <i>none</i>, DEREFS: <i>none</i> ]
+	 */
+	public JDDVars getAutomatonRowVars() {
+		return automatonRowVars;
+	}
+
+	/** Clear the product model and the other JDD references */
+	public void clear() {
+		if (productModel != null) productModel.clear();
+		if (productStatesOfInterest != null) JDD.Deref(productStatesOfInterest);
+		if (automatonRowVars != null) automatonRowVars.derefAll();
+	}
+
+	/**
+	 * Project state values from the product model back to the original model. Clears svTransformed.
+	 * <br>
+	 * Note: This assumes that the product construction results in each state of interest
+	 * in the original model having a unique corresponding state in the product,
+	 * provided by productStatesOfInterest.
+	 * @param svTransformed the state values in the product model
+	 * @return the corresponding state values in the original model
+	 */
+	@Override
+	public StateValues projectToOriginalModel(StateValues svTransformed) throws PrismException {
+		// Filter against the productStatesOfInterest, i.e.,
+		// set values to 0 for all states that do not correspond to the states of interest
+		svTransformed.filter(productStatesOfInterest);
+		// Then sum over the DD vars introduced for the automata modes to
+		// get StateValues in the original model
+		StateValues svOriginal = svTransformed.sumOverDDVars(automatonRowVars, originalModel);
+
+		svTransformed.clear();
+		return svOriginal;
+	}
+
+	@Override
+	public JDDNode getTransformedStatesOfInterest()
+	{
+		return productStatesOfInterest.copy();
+	}
+}