implements AutoCloseable now; TAGS_OBJECTIVE is now public; exiting t…

…raining loop if training finished; adding class label to options again; skipping class attribute from categorical_features parameter; closing optional validation set now as well

src/main/java/weka/classifiers/functions/LightGBM.java

@@ -56,7 +56,7 @@
  */
 public class LightGBM
   extends RandomizableClassifier
-  implements TechnicalInformationHandler {
+  implements TechnicalInformationHandler, AutoCloseable {
 
   private static final long serialVersionUID = -6138516902729782286L;
 
@@ -82,7 +82,7 @@ public class LightGBM
   public static final int OBJECTIVE_RANK_XENDCG = 15;
 
   /** the available objectives. */
-  protected static final Tag[] TAGS_OBJECTIVE = {
+  public static final Tag[] TAGS_OBJECTIVE = {
     new Tag(OBJECTIVE_REGRESSION, "REGRESSION", "Regression"),
     new Tag(OBJECTIVE_REGRESSION_L1, "REGRESSION_L1", "Regression L1"),
     new Tag(OBJECTIVE_HUBER, "HUBER", "Huber loss"),
@@ -279,16 +279,14 @@ public String[] getOptions() {
     result.add("-I");
     result.add("" + getNumIterations());
 
-    result.add("-V");
-    result.add("" + getValidationPercentage());
+    if (getValidationPercentage() > 0) {
+      result.add("-V");
+      result.add("" + getValidationPercentage());
+    }
 
-    if (getRandomizeBeforeSplit()) {
+    if (getRandomizeBeforeSplit())
       result.add("-R");
 
-      result.add("-S");
-      result.add("" + getSeed());
-    }
-
     return result.toArray(new String[0]);
   }
 
@@ -497,6 +495,7 @@ public void buildClassifier(Instances data) throws Exception {
     int		 	i;
     int			size;
     StringBuilder 	categorical;
+    boolean		finished;
 
     // can classifier handle the data?
     getCapabilities().testWithFail(data);
@@ -527,6 +526,8 @@ public void buildClassifier(Instances data) throws Exception {
     // categorical features
     categorical = new StringBuilder();
     for (i = 0; i < data.numAttributes(); i++) {
+      if (i == data.classIndex())
+        continue;
       if (data.attribute(i).isNominal()) {
 	if (categorical.length() > 0)
 	  categorical.append(",");
@@ -538,23 +539,37 @@ public void buildClassifier(Instances data) throws Exception {
     lgbmVal = null;
     if (val != null)
       lgbmVal = LightGBMUtils.fromInstances(val, lgbmTrain);
-    m_ActualParameters = "objective=" + getObjective().getSelectedTag().getIDStr().toLowerCase();
+    m_ActualParameters = "objective=" + getObjective().getSelectedTag().getIDStr().toLowerCase()
+      + " label=name:" + data.classAttribute().name();
     if (categorical.length() > 0)
       m_ActualParameters += " categorical_features=" + categorical.toString();
     if (!m_Parameters.isEmpty())
       m_ActualParameters += " " + m_Parameters;
+    if (getDebug())
+      System.out.println("Actual parameters: " + m_ActualParameters);
 
     try {
       m_Booster = LGBMBooster.create(lgbmTrain, m_ActualParameters);
       if (lgbmVal != null)
 	m_Booster.addValidData(lgbmVal);
-      for (i = 0; i < m_NumIterations; i++)
-	m_Booster.updateOneIter();
+      // train
+      for (i = 0; i < m_NumIterations; i++) {
+	finished = m_Booster.updateOneIter();
+	if (finished) {
+	  System.out.println("No more splits possible, stopping training at iteration " + (i+1) + " out of " + m_NumIterations);
+	  break;
+	}
+      }
       m_Model = m_Booster.saveModelToString(m_NumIterations - 1, m_NumIterations - 1, LGBMBooster.FeatureImportanceType.GAIN);
     }
     catch (Exception e) {
-      // m_Booster.close();  // TODO memory leak?
+      if (m_Booster != null)
+	m_Booster.close();
+    }
+    finally {
       lgbmTrain.close();
+      if (lgbmVal != null)
+	lgbmVal.close();
     }
   }
 
@@ -619,6 +634,21 @@ public String toString() {
     return result.toString();
   }
 
+  /**
+   * Closes this resource, relinquishing any underlying resources.
+   * This method is invoked automatically on objects managed by the
+   * {@code try}-with-resources statement.
+   *
+   * @throws Exception if this resource cannot be closed
+   */
+  @Override
+  public void close() throws Exception {
+    if (m_Booster != null) {
+      m_Booster.close();
+      m_Booster = null;
+    }
+  }
+
   /**
    * Main method.
    *