DroidFish: Better handling of transpositions in ECO classification.

DroidFish/src/org/petero/droidfish/DroidFish.java

@@ -1954,7 +1954,7 @@ public class DroidFish extends Activity
     private String thinkingStr2 = "";
     private String bookInfoStr = "";
     private String ecoInfoStr = "";
-    private boolean ecoInTree = false;
+    private int distToEcoTree = 0;
     private String variantStr = "";
     private ArrayList<ArrayList<Move>> pvMoves = new ArrayList<ArrayList<Move>>();
     private ArrayList<Move> bookMoves = null;
@@ -1966,7 +1966,7 @@ public class DroidFish extends Activity
         thinkingStr2 = ti.statStr;
         bookInfoStr = ti.bookInfo;
         ecoInfoStr = ti.eco;
-        ecoInTree = ti.ecoInTree;
+        distToEcoTree = ti.distToEcoTree;
         pvMoves = ti.pvMoves;
         bookMoves = ti.bookMoves;
         updateThinkingInfo();
@@ -1995,7 +1995,9 @@ public class DroidFish extends Activity
             }
             thinking.setText(s, TextView.BufferType.SPANNABLE);
         }
-        if ((mEcoHints == ECO_HINTS_ALWAYS || (mEcoHints == ECO_HINTS_AUTO && ecoInTree)) &&
+        int maxDistToEcoTree = 10;
+        if ((mEcoHints == ECO_HINTS_ALWAYS ||
+            (mEcoHints == ECO_HINTS_AUTO && distToEcoTree <= maxDistToEcoTree)) &&
             !ecoInfoStr.isEmpty()) {
             String s = thinkingEmpty ? "" : "<br>";
             s += ecoInfoStr;

DroidFish/src/org/petero/droidfish/GUIInterface.java

@@ -60,7 +60,7 @@ public interface GUIInterface {
         public ArrayList<ArrayList<Move>> pvMoves;
         public ArrayList<Move> bookMoves;
         public String eco;
-        public boolean ecoInTree;
+        public int distToEcoTree;
     }
 
     /** Update the computer thinking information. */

DroidFish/src/org/petero/droidfish/book/EcoDb.java

@@ -49,55 +49,103 @@ public class EcoDb {
         return instance;
     }
 
-    /** Get ECO classification for a given tree node. */
+    /** Get ECO classification for a given tree node. Also returns distance in plies to "ECO tree". */
-    public Pair<String,Boolean> getEco(GameTree gt, GameTree.Node node) {
+    public Pair<String,Integer> getEco(GameTree gt) {
-        ArrayList<GameTree.Node> gtNodePath = new ArrayList<GameTree.Node>();
+        ArrayList<Integer> treePath = new ArrayList<Integer>(); // Path to restore gt to original node
+        ArrayList<Pair<GameTree.Node,Boolean>> toCache = new ArrayList<Pair<GameTree.Node,Boolean>>();
+
         int nodeIdx = -1;
-        boolean inEcoTree = true;
+        int distToEcoTree = 0;
-        while (node != null) {
+
+        // Find matching node furtherest from root in the ECO tree
+        boolean checkForDup = true;
+        while (true) {
+            GameTree.Node node = gt.currentNode;
             CacheEntry e = findNode(node);
             if (e != null) {
                 nodeIdx = e.nodeIdx;
-                inEcoTree = e.inEcoTree;
+                distToEcoTree = e.distToEcoTree;
+                checkForDup = false;
                 break;
             }
-            if (node == gt.rootNode) {
+            Short idx = posHashToNodeIdx.get(gt.currentPos.zobristHash());
-                Short idx = posHashToNodeIdx.get(gt.startPos.zobristHash());
+            boolean inEcoTree = idx != null;
-                if (idx != null) {
+            toCache.add(new Pair<GameTree.Node,Boolean>(node, inEcoTree));
+
+            if (idx != null) {
+                Node ecoNode = readNode(idx);
+                if (ecoNode.nameIdx != -1) {
                     nodeIdx = idx;
                     break;
                 }
             }
-            gtNodePath.add(node);
+
-            node = node.getParent();
+            if (node == gt.rootNode)
+                break;
+
+            treePath.add(node.getChildNo());
+            gt.goBack();
         }
-        if (nodeIdx != -1) {
+
-            Node ecoNode = readNode(nodeIdx);
+        // Handle duplicates in ECO tree (same position reachable from more than one path)
-            for (int i = gtNodePath.size() - 1; i >= 0; i--) {
+        if (nodeIdx != -1 && checkForDup && gt.startPos.zobristHash() == startPosHash) {
-                GameTree.Node gtNode = gtNodePath.get(i);
+            ArrayList<Short> dups = posHashToNodeIdx2.get(gt.currentPos.zobristHash());
-                int m = gtNode.move.getCompressedMove();
+            if (dups != null) {
-                int child = inEcoTree ? ecoNode.firstChild : -1;
+                while (gt.currentNode != gt.rootNode) {
-                while (child != -1) {
+                    treePath.add(gt.currentNode.getChildNo());
-                    Node cNode = readNode(child);
+                    gt.goBack();
-                    if (cNode.move == m)
+                }
-                        break;
+
-                    child = cNode.nextSibling;
+                int currEcoNode = 0;
+                boolean foundDup = false;
+                while (!treePath.isEmpty()) {
+                    gt.goForward(treePath.get(treePath.size() - 1));
+                    treePath.remove(treePath.size() - 1);
+                    int m = gt.currentNode.move.getCompressedMove();
+
+                    Node ecoNode = readNode(currEcoNode);
+                    boolean foundChild = false;
+                    int child = ecoNode.firstChild;
+                    while (child != -1) {
+                        ecoNode = readNode(child);
+                        if (ecoNode.move == m) {
+                            foundChild = true;
+                            break;
+                        }
+                        child = ecoNode.nextSibling;
+                    }
+                    if (!foundChild)
+                        break;
+                    currEcoNode = child;
+                    for (Short dup : dups) {
+                        if (dup == currEcoNode) {
+                            nodeIdx = currEcoNode;
+                            foundDup = true;
+                            break;
+                        }
+                    }
+                    if (foundDup)
+                        break;
                 }
-                if (child != -1) {
-                    nodeIdx = child;
-                    ecoNode = readNode(nodeIdx);
-                } else
-                    inEcoTree = false;
-                cacheNode(gtNode, nodeIdx, inEcoTree);
             }
         }
 
+        for (int i = treePath.size() - 1; i >= 0; i--)
+            gt.goForward(treePath.get(i));
+        for (int i = toCache.size() - 1; i >= 0; i--) {
+            Pair<GameTree.Node,Boolean> p = toCache.get(i);
+            distToEcoTree++;
+            if (p.second)
+                distToEcoTree = 0;
+            cacheNode(p.first, nodeIdx, distToEcoTree);
+        }
+
         if (nodeIdx != -1) {
             Node n = readNode(nodeIdx);
             if (n.nameIdx >= 0)
-                return new Pair<String, Boolean>(ecoNames[n.nameIdx], inEcoTree);
+                return new Pair<String, Integer>(ecoNames[n.nameIdx], distToEcoTree);
         }
-        return new Pair<String, Boolean>("", false);
+        return new Pair<String, Integer>("", 0);
     }
 
 
@@ -111,13 +159,15 @@ public class EcoDb {
     private byte[] nodesBuffer;
     private String[] ecoNames;
     private HashMap<Long, Short> posHashToNodeIdx;
+    private HashMap<Long, ArrayList<Short>> posHashToNodeIdx2; // Handles collisions
+    private final long startPosHash; // Zobrist hash for standard starting position
 
     private static class CacheEntry {
         final int nodeIdx;
-        final boolean inEcoTree;
+        final int distToEcoTree;
-        CacheEntry(int n, boolean i) {
+        CacheEntry(int n, int d) {
             nodeIdx = n;
-            inEcoTree = i;
+            distToEcoTree = d;
         }
     }
     private WeakLRUCache<GameTree.Node, CacheEntry> gtNodeToIdx;
@@ -128,13 +178,14 @@ public class EcoDb {
     }
 
     /** Store GameTree.Node to Node index in cache. */
-    private void cacheNode(GameTree.Node node, int nodeIdx, boolean inTree) {
+    private void cacheNode(GameTree.Node node, int nodeIdx, int distToEcoTree) {
-        gtNodeToIdx.put(node, new CacheEntry(nodeIdx, inTree));
+        gtNodeToIdx.put(node, new CacheEntry(nodeIdx, distToEcoTree));
     }
 
     /** Constructor. */
     private EcoDb(Context context) {
         posHashToNodeIdx = new HashMap<Long, Short>();
+        posHashToNodeIdx2 = new HashMap<Long, ArrayList<Short>>();
         gtNodeToIdx = new WeakLRUCache<GameTree.Node, CacheEntry>(50);
         try {
             ByteArrayOutputStream bufStream = new ByteArrayOutputStream();
@@ -174,19 +225,32 @@ public class EcoDb {
             throw new RuntimeException("Can't read ECO database");
         }
         try {
+            Position pos = TextIO.readFEN(TextIO.startPosFEN);
+            startPosHash = pos.zobristHash();
             if (nodesBuffer.length > 0) {
-                Position pos = TextIO.readFEN(TextIO.startPosFEN);
                 populateCache(pos, 0);
             }
         } catch (ChessParseError e) {
+            throw new RuntimeException("Internal error");
         }
     }
 
-    /** Initialize popHashToNodeIdx. */
+    /** Initialize posHashToNodeIdx. */
     private void populateCache(Position pos, int nodeIdx) {
-        if (posHashToNodeIdx.get(pos.zobristHash()) == null)
-            posHashToNodeIdx.put(pos.zobristHash(), (short)nodeIdx);
         Node node = readNode(nodeIdx);
+        long hash = pos.zobristHash();
+        if (posHashToNodeIdx.get(hash) == null) {
+            posHashToNodeIdx.put(hash, (short)nodeIdx);
+        } else if (node.nameIdx != -1) {
+            ArrayList<Short> lst = null;
+            if (posHashToNodeIdx2.get(hash) == null) {
+                lst = new ArrayList<Short>();
+                posHashToNodeIdx2.put(hash, lst);
+            } else {
+                lst = posHashToNodeIdx2.get(hash);
+            }
+            lst.add((short)nodeIdx);
+        }
         int child = node.firstChild;
         UndoInfo ui = new UndoInfo();
         while (child != -1) {

DroidFish/src/org/petero/droidfish/buildtools/EcoBuilder.java

@@ -78,22 +78,10 @@ public class EcoBuilder {
             gotMoves |= !isHeader;
         }
         readGame(pgn.toString());
-        setNameIndices(0);
 
         writeDataFile(ecoDatFile);
     }
 
-    /** For all tree nodes, if nameIndex not already set,
-     *  set it from parent node nameIndex. */
-    private void setNameIndices(int nodeIdx) {
-        Node n = nodes.get(nodeIdx);
-        for (Node c : n.children) {
-            if (c.nameIdx == -1)
-                c.nameIdx = n.nameIdx;
-            setNameIndices(c.index);
-        }
-    }
-
     /** Read and process one game. */
     private void readGame(String pgn) throws Throwable {
         if (pgn.isEmpty())
@@ -142,7 +130,7 @@ public class EcoBuilder {
                 Node node = new Node();
                 node.index = nodes.size();
                 node.move = m;
-                node.nameIdx = parent.nameIdx;
+                node.nameIdx = -1;
                 node.parent = parent;
                 nodes.add(node);
                 parent.children.add(node);

DroidFish/src/org/petero/droidfish/gamelogic/DroidChessController.java

@@ -684,7 +684,7 @@ public class DroidChessController {
         private String bookInfo = "";
         private ArrayList<Move> bookMoves = null;
         private String eco = ""; // ECO classification
-        private boolean ecoInTree = false; // True if current position is inside the EcoDB tree
+        private int distToEcoTree = 0; // Number of plies since game was in the "ECO tree".
 
         private Move ponderMove = null;
         private ArrayList<PvInfo> pvInfoV = new ArrayList<PvInfo>();
@@ -698,7 +698,7 @@ public class DroidChessController {
             bookInfo = "";
             bookMoves = null;
             eco = "";
-            ecoInTree = false;
+            distToEcoTree = 0;
             setSearchInfo(id);
         }
 
@@ -789,7 +789,7 @@ public class DroidChessController {
             ti.statStr = statStr;
             ti.bookInfo = bookInfo;
             ti.eco = eco;
-            ti.ecoInTree = ecoInTree;
+            ti.distToEcoTree = distToEcoTree;
             ti.pvMoves = pvMoves;
             ti.bookMoves = bookMoves;
             latestThinkingInfo = ti;
@@ -863,11 +863,11 @@ public class DroidChessController {
 
         @Override
         public void notifyBookInfo(int id, String bookInfo, ArrayList<Move> moveList,
-                                   String eco, boolean ecoInTree) {
+                                   String eco, int distToEcoTree) {
             this.bookInfo = bookInfo;
             bookMoves = moveList;
             this.eco = eco;
-            this.ecoInTree = ecoInTree;
+            this.distToEcoTree = distToEcoTree;
             setSearchInfo(id);
         }
 
@@ -931,11 +931,10 @@ public class DroidChessController {
     private final void updateBookHints() {
         if (game != null) {
             Pair<String, ArrayList<Move>> bi = computerPlayer.getBookHints(game.currPos(), localPt());
-            Pair<String, Boolean> ecoData =
+            Pair<String, Integer> ecoData =
-                    EcoDb.getInstance(gui.getContext()).getEco(game.tree, game.tree.currentNode);
+                    EcoDb.getInstance(gui.getContext()).getEco(game.tree);
             String eco = ecoData.first;
-            boolean ecoInTree = ecoData.second;
+            listener.notifyBookInfo(searchId, bi.first, bi.second, eco, ecoData.second);
-            listener.notifyBookInfo(searchId, bi.first, bi.second, eco, ecoInTree);
         }
     }
 
@@ -975,11 +974,10 @@ public class DroidChessController {
                 computerPlayer.queueAnalyzeRequest(sr);
             } else if (computersTurn || ponder) {
                 listener.clearSearchInfo(searchId);
-                Pair<String, Boolean> ecoData =
+                Pair<String, Integer> ecoData =
-                        EcoDb.getInstance(gui.getContext()).getEco(game.tree, game.tree.currentNode);
+                        EcoDb.getInstance(gui.getContext()).getEco(game.tree);
                 String eco = ecoData.first;
-                boolean ecoInTree = ecoData.second;
+                listener.notifyBookInfo(searchId, "", null, eco, ecoData.second);
-                listener.notifyBookInfo(searchId, "", null, eco, ecoInTree);
                 final Pair<Position, ArrayList<Move>> ph = game.getUCIHistory();
                 Position currPos = new Position(game.currPos());
                 long now = System.currentTimeMillis();

DroidFish/src/org/petero/droidfish/gamelogic/GameTree.java

@@ -51,7 +51,7 @@ public class GameTree {
 
     public Node rootNode;
     public Node currentNode;
-    Position currentPos;    // Cached value. Computable from "currentNode".
+    public Position currentPos;    // Cached value. Computable from "currentNode".
 
     private final PgnToken.PgnTokenReceiver gameStateListener;
 
@@ -1086,21 +1086,22 @@ public class GameTree {
             ArrayList<Integer> ret = new ArrayList<Integer>(64);
             Node node = this;
             while (node.parent != null) {
-                Node p = node.parent;
+                ret.add(node.getChildNo());
-                int childNo = -1;
-                for (int i = 0; i < p.children.size(); i++)
-                    if (p.children.get(i) == node) {
-                        childNo = i;
-                        break;
-                    }
-                if (childNo == -1) throw new RuntimeException();
-                ret.add(childNo);
                 node = node.parent;
             }
             Collections.reverse(ret);
             return ret;
         }
 
+        /** Return this node's position in the parent node child list. */
+        public final int getChildNo() {
+            Node p = parent;
+            for (int i = 0; i < p.children.size(); i++)
+                if (p.children.get(i) == this)
+                    return i;
+            throw new RuntimeException();
+        }
+
         static final void writeToStream(DataOutputStream dos, Node node) throws IOException {
             while (true) {
                 dos.writeUTF(node.moveStr);

DroidFish/src/org/petero/droidfish/gamelogic/SearchListener.java

@@ -72,7 +72,7 @@ public interface SearchListener {
 
     /** Report opening book information. */
     public void notifyBookInfo(int id, String bookInfo, ArrayList<Move> moveList,
-                               String eco, boolean ecoInTree);
+                               String eco, int distToEcoTree);
 
     /** Report move (or command, such as "resign") played by the engine. */
     public void notifySearchResult(int id, String cmd, Move ponder);

DroidFishTest/src/org/petero/droidfish/book/EcoTest.java

@@ -36,27 +36,27 @@ public class EcoTest extends AndroidTestCase {
         {
             String pgn = "e4 e5 Nf3 Nc6 Bb5 a6 Ba4 Nf6 O-O Be7 Re1";
             GameTree gt = readPGN(pgn);
-            String eco = ecoDb.getEco(gt, gt.currentNode).first;
+            String eco = ecoDb.getEco(gt).first;
             assertEquals("", eco);
 
             gt.goForward(0);
-            eco = ecoDb.getEco(gt, gt.currentNode).first;
+            eco = ecoDb.getEco(gt).first;
             assertEquals("B00: King's pawn opening", eco);
 
             gt.goForward(0);
-            eco = ecoDb.getEco(gt, gt.currentNode).first;
+            eco = ecoDb.getEco(gt).first;
             assertEquals("C20: King's pawn game", eco);
 
             gt.goForward(0);
-            eco = ecoDb.getEco(gt, gt.currentNode).first;
+            eco = ecoDb.getEco(gt).first;
             assertEquals("C40: King's knight opening", eco);
         
             gt.goForward(0);
-            eco = ecoDb.getEco(gt, gt.currentNode).first;
+            eco = ecoDb.getEco(gt).first;
             assertEquals("C44: King's pawn game", eco);
         
             gt.goForward(0);
-            eco = ecoDb.getEco(gt, gt.currentNode).first;
+            eco = ecoDb.getEco(gt).first;
             assertEquals("C60: Ruy Lopez (Spanish opening)", eco);
         }
         {
@@ -65,60 +65,85 @@ public class EcoTest extends AndroidTestCase {
             game.processString("e5");
             game.processString("Nf3");
             game.processString("Nf6");
-            String eco = ecoDb.getEco(game.tree, game.tree.currentNode).first;
+            String eco = ecoDb.getEco(game.tree).first;
             assertEquals("C42: Petrov's defence", eco);
 
             game.processString("Nxe5");
-            eco = ecoDb.getEco(game.tree, game.tree.currentNode).first;
+            eco = ecoDb.getEco(game.tree).first;
             assertEquals("C42: Petrov's defence", eco);
 
             game.processString("d6");
-            eco = ecoDb.getEco(game.tree, game.tree.currentNode).first;
+            eco = ecoDb.getEco(game.tree).first;
             assertEquals("C42: Petrov's defence", eco);
 
             game.processString("Nxf7");
-            eco = ecoDb.getEco(game.tree, game.tree.currentNode).first;
+            eco = ecoDb.getEco(game.tree).first;
             assertEquals("C42: Petrov, Cochrane gambit", eco);
 
             game.undoMove();
-            eco = ecoDb.getEco(game.tree, game.tree.currentNode).first;
+            eco = ecoDb.getEco(game.tree).first;
             assertEquals("C42: Petrov's defence", eco);
 
             game.processString("Nf3");
             game.processString("Nxe4");
             game.processString("d4");
-            eco = ecoDb.getEco(game.tree, game.tree.currentNode).first;
+            eco = ecoDb.getEco(game.tree).first;
             assertEquals("C42: Petrov, classical attack", eco);
         }
         {
             Game game = new Game(null, new TimeControlData());
             game.processString("e4");
             game.processString("c5");
-            String eco = ecoDb.getEco(game.tree, game.tree.currentNode).first;
+            String eco = ecoDb.getEco(game.tree).first;
             assertEquals("B20: Sicilian defence", eco);
 
             game.processString("h3");
-            eco = ecoDb.getEco(game.tree, game.tree.currentNode).first;
+            eco = ecoDb.getEco(game.tree).first;
             assertEquals("B20: Sicilian defence", eco);
 
             game.processString("Nc6");
-            eco = ecoDb.getEco(game.tree, game.tree.currentNode).first;
+            eco = ecoDb.getEco(game.tree).first;
             assertEquals("B20: Sicilian defence", eco);
 
             game.processString("g3");
-            eco = ecoDb.getEco(game.tree, game.tree.currentNode).first;
+            eco = ecoDb.getEco(game.tree).first;
             assertEquals("B20: Sicilian defence", eco);
         }
+        {
+            Game game = new Game(null, new TimeControlData());
+            for (String m : new String[]{"d4", "d5", "c4", "c6", "Nf3", "Nf6", "Nc3", "g6"})
+                game.processString(m);
+            String eco = ecoDb.getEco(game.tree).first;
+            assertEquals("D15: QGD Slav, Schlechter variation", eco);
+            assertEquals(0, ecoDb.getEco(game.tree).second.intValue());
+            game.processString("a4");
+            assertEquals("D15: QGD Slav, Schlechter variation", eco);
+            assertEquals(1, ecoDb.getEco(game.tree).second.intValue());
+        }
+        {
+            Game game = new Game(null, new TimeControlData());
+            for (String m : new String[]{"d4", "Nf6", "c4", "g6", "Nc3", "d5", "Nf3", "c6"})
+                game.processString(m);
+            String eco = ecoDb.getEco(game.tree).first;
+            assertEquals("D90: Gruenfeld, Schlechter variation", eco);
+            assertEquals(0, ecoDb.getEco(game.tree).second.intValue());
+            game.processString("h4");
+            assertEquals("D90: Gruenfeld, Schlechter variation", eco);
+            assertEquals(1, ecoDb.getEco(game.tree).second.intValue());
+            game.processString("h5");
+            assertEquals("D90: Gruenfeld, Schlechter variation", eco);
+            assertEquals(2, ecoDb.getEco(game.tree).second.intValue());
+        }
     }
 
     public void testEcoFromFEN() throws Throwable {
         EcoDb ecoDb = EcoDb.getInstance(getContext());
-        GameTree gt = gtFromFEN("rnbqkbnr/ppp2ppp/8/3p4/3P4/8/PPP2PPP/RNBQKBNR w KQkq - 0 4");
+        GameTree gt = gtFromFEN("rnbqkbnr/ppp2ppp/4p3/3P4/3P4/8/PPP2PPP/RNBQKBNR b KQkq - 0 3");
-        String eco = ecoDb.getEco(gt, gt.currentNode).first;
+        String eco = ecoDb.getEco(gt).first;
         assertEquals("C01: French, exchange variation", eco);
-
+        
         gt = gtFromFEN("rnbqk1nr/ppppppbp/6p1/8/3PP3/8/PPP2PPP/RNBQKBNR w KQkq - 1 3");
-        eco = ecoDb.getEco(gt, gt.currentNode).first;
+        eco = ecoDb.getEco(gt).first;
         assertEquals("B06: Robatsch (modern) defence", eco);
     }