SimilarityCalculator refactoring.

Author: felipexw

src/main/java/com/github/felipexw/evaluations/metrics/EuclidianSimilarityCalculator.java

@@ -1,17 +1,20 @@
 package com.github.felipexw.evaluations.metrics;
 
+import java.util.List;
+
 /**
  * Created by felipe.appio on 23/08/2016.
  */
 public class EuclidianSimilarityCalculator implements SimilarityCalculator {
+
     @Override
-    public double calculate(double[] a, double[] b) {
-        if (a == null || a.length == 0 || (a.length != b.length))
+    public double calculate(List<Double> a, List<Double> b) {
+        if (a == null || a.isEmpty() || (a.size()!= b.size()))
             throw new IllegalArgumentException("The params can't be null or empty.");
         double distance = 0;
 
-        for (short i = 0; i < a.length; i++) {
-            double difference = b[i] - a[i];
+        for (int i = 0; i < a.size(); i++) {
+            double difference = b.get(i) - a.get(i);
             distance += Math.pow(difference, 2);
         }
         return Math.round(Math.sqrt(distance));

src/main/java/com/github/felipexw/evaluations/metrics/JaccardSimilarityCalculator.java

@@ -1,16 +1,18 @@
 package com.github.felipexw.evaluations.metrics;
 
+import java.util.List;
+
 /**
  * Created by felipe.appio on 25/08/2016.
  */
 public class JaccardSimilarityCalculator implements SimilarityCalculator {
     @Override
-    public double calculate(double[] a, double[] b) {
-        if (a == null || b == null)
+    public double calculate(List<Double> a, List<Double> b) {
+        if (a == null || b == null || a.size() != b.size())
             throw new IllegalArgumentException("args can't be invalid");
         double similarity = 0d;
-        for(int i =0; i < a.length; i++){
-            similarity += Math.abs(a[i] - b[i]);
+        for(int i =0; i < a.size(); i++){
+            similarity += Math.abs(a.get(i) - b.get(i));
         }
         return similarity;
     }

src/main/java/com/github/felipexw/evaluations/metrics/MahalanobisSimilarityCalculator.java

@@ -1,11 +1,13 @@
 package com.github.felipexw.evaluations.metrics;
 
+import java.util.List;
+
 /**
  * Created by felipe.appio on 25/08/2016.
  */
 public class MahalanobisSimilarityCalculator implements  SimilarityCalculator{
     @Override
-    public double calculate(double[] a, double[] b) {
+    public double calculate(List<Double> a, List<Double> b) {
         return 0;
     }
 }

src/main/java/com/github/felipexw/evaluations/metrics/ManhattanSimilarityCalculator.java

@@ -1,17 +1,19 @@
 package com.github.felipexw.evaluations.metrics;
 
+import java.util.List;
+
 /**
  * Created by felipe.appio on 25/08/2016.
  */
 public class ManhattanSimilarityCalculator implements SimilarityCalculator {
     @Override
-    public double calculate(double[] a, double[] b) {
-        if (a == null || a.length == 0)
+    public double calculate(List<Double> a, List<Double> b) {
+        if (a == null || a.size() == 0)
             throw new IllegalArgumentException("The params can't be null or empty.");
         double distance = 0;
 
-        for (short i = 0; i < a.length; i++) {
-            double difference = Math.abs(b[i] - a[i]);
+        for (short i = 0; i < a.size(); i++) {
+            double difference = Math.abs(b.get(i) - a.get(i));
             distance += difference;
         }
         return distance;

src/main/java/com/github/felipexw/evaluations/metrics/MinkowskiSimilarityCalculator.java

@@ -1,12 +1,14 @@
 package com.github.felipexw.evaluations.metrics;
 
+import java.util.List;
+
 /**
  * Created by felipe.appio on 25/08/2016.
  */
 public class MinkowskiSimilarityCalculator implements SimilarityCalculator {
 
     @Override
-    public double calculate(double[] a, double[] b) {
+    public double calculate(List<Double> a, List<Double> b) {
         return 0;
     }
 }

src/main/java/com/github/felipexw/evaluations/metrics/PearsonSimilarityCalculator.java

@@ -1,5 +1,7 @@
 package com.github.felipexw.evaluations.metrics;
 
+import java.util.List;
+
 /**
  * Created by felipe.appio on 25/08/2016.
  */
@@ -16,8 +18,8 @@ public class PearsonSimilarityCalculator implements SimilarityCalculator {
      *              * 0  means the datapoints doesn't have a correlation among them.
      */
     @Override
-    public double calculate(double[] a, double[] b) {
-        if (a == null || a.length == 0)
+    public double calculate(List<Double> a, List<Double> b) {
+        if (a == null || a.size() == 0)
             throw new IllegalArgumentException("The params can't be null or empty.");
         double distance = 0;
 
@@ -26,9 +28,9 @@ public double calculate(double[] a, double[] b) {
         double aVariance= 0;
         double bVariance = 0;
 
-        for (short i = 0; i < a.length; i++) {
-            aVariance += a[i] * avgFeaturesA;
-            bVariance += b[i] * avgFeaturesB;
+        for (short i = 0; i < a.size(); i++) {
+            aVariance += a.get(i) * avgFeaturesA;
+            bVariance += b.get(i) * avgFeaturesB;
         }
 
         double numerator = aVariance * bVariance;
@@ -37,12 +39,12 @@ public double calculate(double[] a, double[] b) {
         return numerator/denominator;
     }
 
-    private double getAvearageFromFeatures(double[] features){
+    private double getAvearageFromFeatures(List<Double> features){
         double average = 0;
 
-        for(int i =0; i < features.length; i++)
-            average += features[i];
+        for(int i =0; i < features.size(); i++)
+            average += features.get(i);
 
-        return average/features.length;
+        return average/features.size();
     }
 }

src/main/java/com/github/felipexw/evaluations/metrics/SimilarityCalculator.java

@@ -1,9 +1,13 @@
 package com.github.felipexw.evaluations.metrics;
 
+import java.util.List;
+
 /**
  * Created by felipe.appio on 23/08/2016.
  */
 public interface SimilarityCalculator {
 
-    double calculate(double[] a, double[] b);
+    double calculate(List<Double> a, List<Double> b);
+
+
 }

src/test/java/SimilarityCalculatorCalculatorTest.java

@@ -2,6 +2,9 @@
 import com.google.common.truth.Truth;
 import org.junit.Test;
 
+import java.util.Arrays;
+import java.util.List;
+
 
 /**
  * Created by felipe.appio on 24/08/2016.
@@ -18,7 +21,7 @@ public void itShouldRaiseAnExceptionWithNullArgs() {
     @Test
     public void it_should_calculate_the_euclidian_distance_between_5_And_2() {
         SimilarityCalculator similarityCalculator = new EuclidianSimilarityCalculator();
-        double found = similarityCalculator.calculate(new double[]{3}, new double[]{5});
+        double found = similarityCalculator.calculate(Arrays.asList(0d, 1d), Arrays.asList(0d));
         double expected = Math.round(2.449489742783178);
         Truth.assertThat(found).isEqualTo(expected);
     }
@@ -38,7 +41,7 @@ public void when_calculate_the_manhattan_distance_with_empty_point_it_should_rai
     @Test
     public void it_should_calculate_the_mahattan_distance_between_5_And_2() {
         SimilarityCalculator similarityCalculator = new ManhattanSimilarityCalculator();
-        double found = similarityCalculator.calculate(new double[]{3, 2, 50}, new double[]{5, 2, 10});
+        double found = similarityCalculator.calculate(Arrays.asList(3d, 2d, 50d), Arrays.asList(5d, 2d, 10d));
         double expected = 42d;
 
         Truth.assertThat(found).isEqualTo(expected);
@@ -59,7 +62,7 @@ public void when_calculate_the_cosine_distance_with_invalid_args_it_should_raise
     @Test(expected = IllegalArgumentException.class)
     public void when_calculate_the_cosine_distance_with_different_args_dimensions_it_should_raise_an_exception() {
         SimilarityCalculator similarityCalculator = new CosineSimilarityCalculator();
-        similarityCalculator.calculate(new double[3], new double[2]);
+        similarityCalculator.calculate(Arrays.asList(1d), Arrays.asList(2d, 3d));
     }
 
     @Test()
@@ -68,8 +71,10 @@ public void when_calculate_the_jaccard_distance_between_two_feature_vectors() {
          * A(2,2); B(2,2)
          */
         SimilarityCalculator similarityCalculator = new JaccardSimilarityCalculator();
-        double similarity = similarityCalculator.calculate(new double[]{2d, 2d}, new double[]{2d, 2d});
+        List<Double> a = Arrays.asList(2d, 2d);
+        List<Double> b = Arrays.asList(2d, 2d);
         double expectedSimilarity = 0d;
+        double similarity = similarityCalculator.calculate(a,b);
 
         Truth.assertThat(similarity)
                 .isEqualTo(expectedSimilarity);
@@ -81,7 +86,10 @@ public void when_calculate_the_cosine_distance_between_two_feature_vectors() {
          * A(2,2); B(2,2)
          */
         SimilarityCalculator similarityCalculator = new JaccardSimilarityCalculator();
-        double similarity = similarityCalculator.calculate(new double[]{2d, 2d}, new double[]{2d, 2d});
+        List<Double> a = Arrays.asList(2d, 2d);
+        List<Double> b = Arrays.asList(2d, 2d);
+
+        double similarity = similarityCalculator.calculate(a, b);
         double expectedSimilarity = 0d;
 
         Truth.assertThat(similarity)