Fix issue #3

src/main/java/be/cylab/java/wowa/training/Trainer.java

@@ -528,13 +528,13 @@ public class Trainer {
      */
     private void checkAndCorrectNullWeightVector(final AbstractSolution child) {
         if (Utils.sumListElements(child.getWeightsW()) == 0) {
-            int index = Utils.randomInteger(0, child.getWeightsW().size()) - 1;
+            int index = Utils.randomInteger(0, child.getWeightsW().size() - 1);
             List<Double> w = child.getWeightsW();
             w.set(index, 1.0);
             child.setWeightsW(w);
         }
         if (Utils.sumListElements(child.getWeightsP()) == 0) {
-            int index = Utils.randomInteger(0, child.getWeightsP().size()) - 1;
+            int index = Utils.randomInteger(0, child.getWeightsP().size() - 1);
             List<Double> p = child.getWeightsP();
             p.set(index, 1.0);
             child.setWeightsP(p);

src/main/java/be/cylab/java/wowa/training/Utils.java

@@ -34,7 +34,7 @@ final class Utils {
      * @return
      */
     public static List<Double> normalizeWeights(final List<Double> weights) {
-        double sum_weight = Utils.sumListElements(weights);
+        Double sum_weight = Utils.sumListElements(weights);
         List<Double> weights_normalized = new ArrayList<>();
         for (int i = 0; i < weights.size(); i++) {
             weights_normalized.add(weights.get(i) / sum_weight);
@@ -97,8 +97,8 @@ final class Utils {
      * @param array
      * @return
      */
-    public static double sumListElements(final List<Double> array) {
-        float sum = 0;
+    public static Double sumListElements(final List<Double> array) {
+        Double sum = 0.0;
         for (Double weight : array) {
             sum += weight;
         }