(Dl4j) performance improvments (#9078)

* Removed invoking the boolean constructor

Signed-off-by: Dariusz Zbyrad <dariusz.zbyrad@gmail.com>

* Use bulk operations instead of iteration

Signed-off-by: Dariusz Zbyrad <dariusz.zbyrad@gmail.com>

* Removed manuall array copy

Signed-off-by: Dariusz Zbyrad <dariusz.zbyrad@gmail.com>

deeplearning4j/deeplearning4j-modelimport/src/main/java/org/deeplearning4j/nn/modelimport/keras/preprocessing/text/KerasTokenizer.java

@@ -205,9 +205,7 @@ public class KerasTokenizer {
         ArrayList<String> sortedVocabulary = new ArrayList<>();
         if (outOfVocabularyToken != null)
             sortedVocabulary.add(outOfVocabularyToken);
-        for (String word: sortedWordCounts.keySet()) {
-            sortedVocabulary.add(word);
-        }
+        sortedVocabulary.addAll(sortedWordCounts.keySet());
 
         for (int i = 0; i < sortedVocabulary.size(); i++)
             wordIndex.put(sortedVocabulary.get(i), i+1);

deeplearning4j/deeplearning4j-modelimport/src/main/java/org/deeplearning4j/nn/modelimport/keras/preprocessors/ReshapePreprocessor.java

@@ -96,9 +96,7 @@ public class ReshapePreprocessor extends BaseInputPreProcessor {
         int shapeLength = shape.length;
         val miniBatchShape = new long[shapeLength + 1];
         miniBatchShape[0] = miniBatchSize;
-        for (int i = 1; i < miniBatchShape.length; i++) {
-            miniBatchShape[i] = shape[i - 1];
-        }
+        System.arraycopy(shape, 0, miniBatchShape, 1, miniBatchShape.length - 1);
         return miniBatchShape;
     }
 

deeplearning4j/deeplearning4j-nlp-parent/deeplearning4j-nlp-chinese/src/main/java/org/ansj/recognition/impl/BookRecognition.java

@@ -67,9 +67,7 @@ public class BookRecognition implements Recognition {
         }
 
         if (mergeList != null) {
-            for (Term term : list) {
-                list.add(term);
-            }
+            list.addAll(list);
         }
 
         result.setTerms(list);

deeplearning4j/deeplearning4j-nlp-parent/deeplearning4j-nlp-chinese/src/main/java/org/ansj/recognition/impl/StopRecognition.java

@@ -48,9 +48,7 @@ public class StopRecognition implements Recognition {
      * @return
      */
     public StopRecognition insertStopWords(String... stopWords) {
-        for (String words : stopWords) {
-            stop.add(words);
-        }
+        stop.addAll(Arrays.asList(stopWords));
         return this;
     }
 
@@ -60,9 +58,7 @@ public class StopRecognition implements Recognition {
      * @param stopWords
      */
     public void insertStopNatures(String... stopNatures) {
-        for (String natureStr : stopNatures) {
-            natureStop.add(natureStr);
-        }
+        natureStop.addAll(Arrays.asList(stopNatures));
     }
 
     /**

deeplearning4j/deeplearning4j-nlp-parent/deeplearning4j-nlp/src/main/java/org/deeplearning4j/models/word2vec/wordstore/VocabularyHolder.java

@@ -345,9 +345,8 @@ public class VocabularyHolder implements Serializable {
             if (word.getRetentionStep() < retentionDelay - 1) {
                 word.incrementRetentionStep();
             } else {
-                for (int x = 1; x < retentionDelay; x++) {
-                    word.getFrequencyShift()[x - 1] = word.getFrequencyShift()[x];
-                }
+                if (retentionDelay - 1 >= 0)
+                    System.arraycopy(word.getFrequencyShift(), 1, word.getFrequencyShift(), 0, retentionDelay - 1);
             }
         }
         logger.info("Scavenger was activated. Vocab size before: [" + initialSize + "],  after: [" + vocabulary.size()

deeplearning4j/deeplearning4j-nn/src/main/java/org/deeplearning4j/nn/graph/vertex/impl/StackVertex.java

@@ -77,9 +77,7 @@ public class StackVertex extends BaseGraphVertex {
 
         // create the new shape
         outShape[0] = nStack * inShape[0];
-        for (int i = 1; i < inShape.length; i++) {
-            outShape[i] = inShape[i];
-        }
+        System.arraycopy(inShape, 1, outShape, 1, inShape.length - 1);
 
         boolean variableLengthTS = false;
         if (inShape.length == 3) {

deeplearning4j/deeplearning4j-nn/src/main/java/org/deeplearning4j/nn/layers/variational/VariationalAutoencoder.java

@@ -838,8 +838,7 @@ public class VariationalAutoencoder implements Layer {
             return;
         }
 
-        for (TrainingListener listener : listeners)
-            trainingListeners.add(listener);
+        trainingListeners.addAll(Arrays.asList(listeners));
     }
 
     @Override

deeplearning4j/deeplearning4j-scaleout/spark/dl4j-spark-parameterserver/src/main/java/org/deeplearning4j/spark/parameterserver/training/SharedTrainingMaster.java

@@ -915,7 +915,7 @@ public class SharedTrainingMaster extends BaseTrainingMaster<SharedTrainingResul
         protected int numWorkersPerNode = -1;
         protected int workerPrefetchNumBatches = 2;
         protected Repartitioner repartitioner = new DefaultRepartitioner();
-        protected Boolean workerTogglePeriodicGC = new Boolean(true);
+        protected Boolean workerTogglePeriodicGC = Boolean.TRUE;
         protected Integer workerPeriodicGCFrequency = new Integer(5000);
         protected boolean encodingDebugMode = false;