1 files changed, 149 insertions, 0 deletions
diff --git a/src/de/lmu/ifi/dbs/elki/evaluation/clustering/pairsegments/Segment.java b/src/de/lmu/ifi/dbs/elki/evaluation/clustering/pairsegments/Segment.java
new file mode 100644
index 00000000..8ce8fd4a
--- /dev/null
+++ b/src/de/lmu/ifi/dbs/elki/evaluation/clustering/pairsegments/Segment.java
@@ -0,0 +1,149 @@
+package de.lmu.ifi.dbs.elki.evaluation.clustering.pairsegments;
+
+import java.util.Arrays;
+
+import de.lmu.ifi.dbs.elki.database.ids.DBIDs;
+
+/**
+ * A segment represents a set of pairs that share the same clustering
+ * properties.
+ * 
+ * As such, for each ring (= clustering), a cluster number (or the constant
+ * {@link #UNCLUSTERED}) is stored.
+ */
+public class Segment implements Comparable<Segment> {
+  /**
+   * Object is not clustered
+   */
+  public static final int UNCLUSTERED = -1;
+
+  /**
+   * IDs in segment, for object segments.
+   */
+  protected DBIDs objIDs = null;
+
+  /**
+   * Size of cluster, in pairs.
+   */
+  protected long pairsize = 0;
+
+  /**
+   * The cluster numbers in each ring
+   */
+  protected int[] clusterIds;
+
+  public Segment(int clusterings) {
+    clusterIds = new int[clusterings];
+  }
+
+  public long getPairCount() {
+    return pairsize;
+  }
+
+  /**
+   * Constructor.
+   * 
+   * @param clone Clone of cluster ids
+   */
+  public Segment(int[] clone) {
+    clusterIds = clone;
+  }
+
+  /**
+   * Get cluster number for index idx.
+   * 
+   * @param idx Index
+   * @return Cluster number
+   */
+  public int get(int idx) {
+    return clusterIds[idx];
+  }
+
+  /**
+   * Checks if the segment has a cluster with unpaired objects. Unpaired
+   * clusters are represented by "0" (0 = all).
+   * 
+   * @return true when unclustered in at least one dimension.
+   */
+  public boolean isUnpaired() {
+    for(int id : clusterIds) {
+      if(id == UNCLUSTERED) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  /**
+   * Check if this segment contains the pairs that are never clustered by any of
+   * the clusterings (all 0).
+   * 
+   * @return true when unclustered everywhere
+   */
+  public boolean isNone() {
+    for(int id : clusterIds) {
+      if(id != UNCLUSTERED) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  /**
+   * Returns the index of the first clustering having an unpaired cluster, or -1
+   * no unpaired cluster exists.
+   * 
+   * @return clustering id or -1
+   */
+  public int getUnpairedClusteringIndex() {
+    for(int index = 0; index < clusterIds.length; index++) {
+      if(clusterIds[index] == UNCLUSTERED) {
+        return index;
+      }
+    }
+    return -1;
+  }
+
+  /**
+   * Get the DBIDs of objects contained in this segment.
+   * 
+   * @return the segment IDs
+   */
+  public DBIDs getDBIDs() {
+    return objIDs;
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if(!(Segment.class.isInstance(obj))) {
+      return false;
+    }
+    Segment other = (Segment) obj;
+    return Arrays.equals(clusterIds, other.clusterIds);
+  }
+
+  @Override
+  public int hashCode() {
+    return Arrays.hashCode(clusterIds);
+  }
+
+  @Override
+  public int compareTo(Segment sid) {
+    for(int i = 0; i < clusterIds.length; i++) {
+      final int a = this.clusterIds[i];
+      final int b = sid.clusterIds[i];
+      if(a != b) {
+        if(a * b > 0) {
+          // Regular comparison
+          return (a < b) ? -1 : +1;
+          // return (a < b) ? +1 : -1;
+        }
+        else {
+          // Inverse, to sort negative last
+          return (a < b) ? +1 : -1;
+        }
+      }
+    }
+    return 0;
+  }
+}
+\ No newline at end of file