Import Debian changes 0.6.0~beta2-1

elki (0.6.0~beta2-1) unstable; urgency=low

  * New upstream beta release.
  * 3DPC extension is not yet included.

1 files changed, 95 insertions, 0 deletions

diff --git a/src/de/lmu/ifi/dbs/elki/index/tree/metrical/mtreevariants/strategies/split/MLBDistSplit.java b/src/de/lmu/ifi/dbs/elki/index/tree/metrical/mtreevariants/strategies/split/MLBDistSplit.java
new file mode 100644
index 00000000..d294d5b3
--- /dev/null
+++ b/src/de/lmu/ifi/dbs/elki/index/tree/metrical/mtreevariants/strategies/split/MLBDistSplit.java
@@ -0,0 +1,95 @@
+package de.lmu.ifi.dbs.elki.index.tree.metrical.mtreevariants.strategies.split;
+
+/*
+ This file is part of ELKI:
+ Environment for Developing KDD-Applications Supported by Index-Structures
+
+ Copyright (C) 2013
+ Ludwig-Maximilians-Universität München
+ Lehr- und Forschungseinheit für Datenbanksysteme
+ ELKI Development Team
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU Affero General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU Affero General Public License for more details.
+
+ You should have received a copy of the GNU Affero General Public License
+ along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+import de.lmu.ifi.dbs.elki.database.ids.DBID;
+import de.lmu.ifi.dbs.elki.distance.distancevalue.NumberDistance;
+import de.lmu.ifi.dbs.elki.index.tree.metrical.mtreevariants.AbstractMTree;
+import de.lmu.ifi.dbs.elki.index.tree.metrical.mtreevariants.AbstractMTreeNode;
+import de.lmu.ifi.dbs.elki.index.tree.metrical.mtreevariants.MTreeEntry;
+import de.lmu.ifi.dbs.elki.utilities.documentation.Reference;
+
+/**
+ * Encapsulates the required methods for a split of a node in an M-Tree. The
+ * routing objects are chosen according to the M_LB_DIST strategy.
+ * 
+ * Reference:
+ * <p>
+ * P. Ciaccia, M. Patella, P. Zezula<br />
+ * M-tree: An Efficient Access Method for Similarity Search in Metric Spaces<br />
+ * In Proceedings of 23rd International Conference on Very Large Data Bases
+ * (VLDB'97), August 25-29, 1997, Athens, Greece
+ * </p>
+ * 
+ * @author Elke Achtert
+ * 
+ * @param <O> the type of DatabaseObject to be stored in the M-Tree
+ * @param <D> the type of Distance used in the M-Tree
+ * @param <N> the type of AbstractMTreeNode used in the M-Tree
+ * @param <E> the type of MetricalEntry used in the M-Tree
+ */
+@Reference(authors = "P. Ciaccia, M. Patella, P. Zezula", title = "M-tree: An Efficient Access Method for Similarity Search in Metric Spaces", booktitle = "VLDB'97, Proceedings of 23rd International Conference on Very Large Data Bases, August 25-29, 1997, Athens, Greece", url = "http://www.vldb.org/conf/1997/P426.PDF")
+public class MLBDistSplit<O, D extends NumberDistance<D, ?>, N extends AbstractMTreeNode<O, D, N, E>, E extends MTreeEntry> extends MTreeSplit<O, D, N, E> {
+  /**
+   * Creates a new split object.
+   */
+  public MLBDistSplit() {
+    super();
+  }
+
+  /**
+   * Selects the second object of the specified node to be promoted and stored
+   * into the parent node and partitions the entries according to the M_LB_DIST
+   * strategy.
+   * <p/>
+   * This strategy considers all possible pairs of objects and chooses the pair
+   * of objects for which the distance is maximum.
+   * 
+   * @param tree Tree to use
+   * @param node the node to be split
+   */
+  @Override
+  public Assignments<E> split(AbstractMTree<O, D, N, E, ?> tree, N node) {
+    DBID firstPromoted = null;
+    DBID secondPromoted = null;
+
+    // choose first and second routing object
+    double currentMaxDist = 0.;
+    for (int i = 0; i < node.getNumEntries(); i++) {
+      DBID id1 = node.getEntry(i).getRoutingObjectID();
+      for (int j = i + 1; j < node.getNumEntries(); j++) {
+        DBID id2 = node.getEntry(j).getRoutingObjectID();
+
+        double distance = tree.distance(id1, id2).doubleValue();
+        if (distance >= currentMaxDist) {
+          firstPromoted = id1;
+          secondPromoted = id2;
+          currentMaxDist = distance;
+        }
+      }
+    }
+
+    return balancedPartition(tree, node, firstPromoted, secondPromoted);
+  }
+}