Building the lattice Pt. 2: Edges

src/datastructures/FormalContext.java

@@ -50,30 +50,30 @@ private void writeToFile(String exportString, String outputFile) {
 		catch (UnsupportedEncodingException e) { e.printStackTrace(); }
 	}
 
-	private String createSLFString() {
-		String export = "";
-		export += "[Lattice]\n";
-		export += objects.size() + "\n";
-		export += dic.getSize() + "\n";
-		export += "[Objects]\n";
-		for(FormalObject obj : objects){
-			export += obj.getName() + getObjectNumber(obj.getName()) + "\n";
-		}
-		export += "[Attributes]\n";
-		for(String attr : dic.getContents())
-			export += attr + "\n";
-		export += "[relation]\n";
-		for(FormalObject obj : objects){
-			BitSet bitset = obj.getExtent();
-			String currentObject = "";
-			for(int i = 0; i < dic.getSize(); i++){
-				if(bitset.get(i)) currentObject += "1 ";
-				else currentObject += "0 ";
-			}
-			export += currentObject + "\n";
-		}
-		return export;
-	}
+//	private String createSLFString() {
+//		String export = "";
+//		export += "[Lattice]\n";
+//		export += objects.size() + "\n";
+//		export += dic.getSize() + "\n";
+//		export += "[Objects]\n";
+//		for(FormalObject obj : objects){
+//			export += obj.getName() + getObjectNumber(obj.getName()) + "\n";
+//		}
+//		export += "[Attributes]\n";
+//		for(String attr : dic.getContents())
+//			export += attr + "\n";
+//		export += "[relation]\n";
+//		for(FormalObject obj : objects){
+//			BitSet bitset = obj.getExtent();
+//			String currentObject = "";
+//			for(int i = 0; i < dic.getSize(); i++){
+//				if(bitset.get(i)) currentObject += "1 ";
+//				else currentObject += "0 ";
+//			}
+//			export += currentObject + "\n";
+//		}
+//		return export;
+//	}
 
 	private String createCXTString(){
 		sortObjects();
@@ -119,4 +119,9 @@ private int getObjectNumber(String name){
 	public ArrayList<FormalObject> getObjects() {
 		return objects;
 	}
+
+	//delete?
+	public int numberOfAttributes() {
+		return dic.getSize();
+	}
 }

src/datastructures/Lattice.java

@@ -2,7 +2,10 @@
 
 import java.util.ArrayList;
 import java.util.BitSet;
+import java.util.Collection;
 import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Set;
 
 public class Lattice {
 	private ArrayList<LatticeNode> nodes;
@@ -25,13 +28,12 @@ public void addToNodes(BitSet bs) {
 		nodes.add(newNode);
 		levels.get(card).put(hash, newNode);
 		hashes.put(hash, bs);
-		//System.out.println("adding " + card + " " + hash + " " + levels.get(card).get(hash));
 	}
 
 	public void increaseNodeCount(BitSet bs) {
 		int card = bs.cardinality();
 		int hash = bs.hashCode();
-		//System.out.println("increasing " + card + " " + hash + " " + levels.get(card).get(hash));
+		//TODO: Make prettier
 		LatticeNode node = levels.get(card).get(hash);
 		node.increaseNumberOfObjects();
 		HashMap<Integer, LatticeNode> level = levels.get(card);
@@ -40,18 +42,40 @@ public void increaseNodeCount(BitSet bs) {
 	}
 
 	public void computeEdges() {
-		// TODO Auto-generated method stub
-
+		Set<Integer> differentLevels = levels.keySet(); //ordered!
+		for(int lowerLevel : differentLevels){
+			Iterator<LatticeNode> lowerIt = levels.get(lowerLevel).values().iterator();
+			while(lowerIt.hasNext()){
+				LatticeNode lowerNode = lowerIt.next();
+				BitSet coveredAttributes = (BitSet)lowerNode.getExtent().clone(); //helps avoid transitive duplicates of edges
+				for(int upperLevel : differentLevels){
+					if(0 < lowerLevel && lowerLevel < upperLevel){
+						Iterator<LatticeNode> upperIt = levels.get(upperLevel).values().iterator();
+						while(upperIt.hasNext()){
+							LatticeNode upperNode = upperIt.next();
+							if(lowerNode.isSubsetOf(upperNode)){
+								BitSet covered = (BitSet)coveredAttributes.clone();
+								covered.or(upperNode.getExtent());
+								if(!covered.equals(coveredAttributes)) {//if we haven't "covered" all attributes in the potential new node
+									coveredAttributes.or(upperNode.getExtent());
+									edges.add(new LatticeEdge(lowerNode, upperNode));
+								}
+							}
+						}
+					}	
+				}
+			}
+		}
 	}
-	
+
 	@Override
 	public String toString() {
 		String str = "";
 		str += "\nLattice stats: \n";
 		str += "Different levels: " + levels.keySet() + "\n";
 		str += "Different nodes: " + nodes.size() + "\n";
-		for(LatticeNode ln : nodes)
-			str += ln + "\n";
+//		for(LatticeNode ln : nodes)
+//			str += ln + "\n";
 		return str;
 	}
 }

src/datastructures/LatticeNode.java

@@ -15,8 +15,18 @@ public void increaseNumberOfObjects() {
 		numberOfObjects++;
 	}
 
+	public BitSet getExtent() {
+		return extent;
+	}
+
+	public Boolean isSubsetOf(LatticeNode otherNode){
+		BitSet thisExtent = (BitSet)extent.clone();
+		thisExtent.and(otherNode.getExtent());
+		return(thisExtent.equals(extent));
+	}
+
 	@Override
 	public String toString() {
 		return extent.cardinality() + "\t" + numberOfObjects;
 	}
-}
+}

src/driver/LatticeBuilder.java

@@ -27,6 +27,7 @@ public Lattice buildLattice(FormalContext context){
 		}
 
 		//add edges to lattice
+		//all relevant datastructures are in the lattice, so we do this from there
 		lattice.computeEdges();
 
 		return lattice;