1 files changed, 118 insertions, 0 deletions
diff --git a/src/de/lmu/ifi/dbs/elki/evaluation/classification/holdout/AbstractHoldout.java b/src/de/lmu/ifi/dbs/elki/evaluation/classification/holdout/AbstractHoldout.java
new file mode 100644
index 00000000..af10eac0
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+++ b/src/de/lmu/ifi/dbs/elki/evaluation/classification/holdout/AbstractHoldout.java
@@ -0,0 +1,118 @@
+package de.lmu.ifi.dbs.elki.evaluation.classification.holdout;
+
+/*
+ This file is part of ELKI:
+ Environment for Developing KDD-Applications Supported by Index-Structures
+
+ Copyright (C) 2014
+ 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 java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashSet;
+
+import de.lmu.ifi.dbs.elki.data.ClassLabel;
+import de.lmu.ifi.dbs.elki.data.type.TypeUtil;
+import de.lmu.ifi.dbs.elki.datasource.bundle.MultipleObjectsBundle;
+import de.lmu.ifi.dbs.elki.utilities.exceptions.AbortException;
+
+/**
+ * Split a data set for holdout evaluation.
+ *
+ * @author Erich Schubert
+ */
+public abstract class AbstractHoldout implements Holdout {
+  /**
+   * Labels in the current data set.
+   */
+  protected ArrayList<ClassLabel> labels;
+
+  /**
+   * Column containing the class labels.
+   */
+  protected int labelcol;
+
+  /**
+   * Input data bundle.
+   */
+  protected MultipleObjectsBundle bundle;
+
+  @Override
+  public void initialize(MultipleObjectsBundle bundle) {
+    this.bundle = bundle;
+    this.labelcol = findClassLabelColumn(bundle);
+    this.labels = allClassLabels(bundle);
+  }
+
+  @Override
+  public ArrayList<ClassLabel> getLabels() {
+    return labels;
+  }
+
+  /**
+   * Find the class label column in the given data set.
+   * 
+   * @param bundle Bundle
+   * @return Class label column
+   */
+  public static int findClassLabelColumn(MultipleObjectsBundle bundle) {
+    for(int i = 0, l = bundle.metaLength(); i < l; ++i) {
+      if(TypeUtil.CLASSLABEL.isAssignableFromType(bundle.meta(i))) {
+        return i;
+      }
+    }
+    return -1;
+  }
+
+  /**
+   * Get an array of all class labels in a given data set.
+   * 
+   * @param bundle Bundle
+   * @return Class labels.
+   */
+  public static ArrayList<ClassLabel> allClassLabels(MultipleObjectsBundle bundle) {
+    int col = findClassLabelColumn(bundle);
+    // TODO: automatically infer class labels?
+    if(col < 0) {
+      throw new AbortException("No class label found (try using ClassLabelFilter).");
+    }
+    return allClassLabels(bundle, col);
+  }
+
+  /**
+   * Get an array of all class labels in a given data set.
+   * 
+   * @param bundle Bundle
+   * @param col Column
+   * @return Class labels.
+   */
+  public static ArrayList<ClassLabel> allClassLabels(MultipleObjectsBundle bundle, int col) {
+    HashSet<ClassLabel> labels = new HashSet<ClassLabel>();
+    for(int i = 0, l = bundle.dataLength(); i < l; ++i) {
+      Object o = bundle.data(i, col);
+      if(o == null || !(o instanceof ClassLabel)) {
+        continue;
+      }
+      labels.add((ClassLabel) o);
+    }
+    ArrayList<ClassLabel> ret = new ArrayList<>(labels);
+    Collections.sort(ret);
+    return ret;
+  }
+}