Fix test bug and remove unnecessary validation

Signed-off-by: Ryan Bogan <[email protected]>

Author: ryanbogan

src/main/java/org/opensearch/knn/plugin/script/KNNScoringUtil.java

@@ -96,16 +96,19 @@ public static float l2Squared(List<Number> queryVector, KNNVectorScriptDocValues
      * @return cosine score
      */
     public static float cosinesimilOptimized(float[] queryVector, float[] inputVector, float normQueryVector) {
+        requireEqualDimension(queryVector, inputVector);
+        float dotProduct = 0.0f;
         float normInputVector = 0.0f;
         for (int i = 0; i < queryVector.length; i++) {
+            dotProduct += queryVector[i] * inputVector[i];
             normInputVector += inputVector[i] * inputVector[i];
         }
         float normalizedProduct = normQueryVector * normInputVector;
         if (normalizedProduct == 0) {
             logger.debug("Invalid vectors for cosine. Returning minimum score to put this result to end");
             return 0.0f;
         }
-        return (float) (VectorUtil.dotProduct(queryVector, inputVector) / (Math.sqrt(normalizedProduct)));
+        return (float) (dotProduct / (Math.sqrt(normalizedProduct)));
     }
 
     /**
@@ -140,28 +143,12 @@ public static float cosineSimilarity(List<Number> queryVector, KNNVectorScriptDo
      */
     public static float cosinesimil(float[] queryVector, float[] inputVector) {
         requireEqualDimension(queryVector, inputVector);
-        int numZeroInInput = 0;
-        int numZeroInQuery = 0;
-        float cosine = 0.0f;
-        for (int i = 0; i < inputVector.length; i++) {
-            if (inputVector[i] == 0) {
-                numZeroInInput++;
-            }
-
-            if (queryVector[i] == 0) {
-                numZeroInQuery++;
-            }
-        }
-        if (numZeroInInput == inputVector.length || numZeroInQuery == queryVector.length) {
-            return cosine;
-        }
         try {
-            cosine = VectorUtil.cosine(queryVector, inputVector);
-        } catch (IllegalArgumentException e) {
+            return VectorUtil.cosine(queryVector, inputVector);
+        } catch (IllegalArgumentException | AssertionError e) {
             logger.debug("Invalid vectors for cosine. Returning minimum score to put this result to end");
             return 0.0f;
         }
-        return cosine;
     }
 
     /**

src/test/java/org/opensearch/knn/plugin/script/KNNScoringSpaceTests.java

@@ -47,7 +47,7 @@ public void testL2() {
 
     public void testCosineSimilarity() {
         float[] arrayFloat = new float[] { 1.0f, 2.0f, 3.0f };
-        List<Double> arrayListQueryObject = new ArrayList<>(Arrays.asList(1.0, 2.0, 3.0));
+        List<Double> arrayListQueryObject = new ArrayList<>(Arrays.asList(2.0, 4.0, 6.0));
         float[] arrayFloat2 = new float[] { 2.0f, 4.0f, 6.0f };
         KNNMethodContext knnMethodContext = KNNMethodContext.getDefault();
 
@@ -59,7 +59,7 @@ public void testCosineSimilarity() {
         );
         KNNScoringSpace.CosineSimilarity cosineSimilarity = new KNNScoringSpace.CosineSimilarity(arrayListQueryObject, fieldType);
 
-        assertEquals(3F, cosineSimilarity.scoringMethod.apply(arrayFloat2, arrayFloat), 0.1F);
+        assertEquals(2F, cosineSimilarity.scoringMethod.apply(arrayFloat2, arrayFloat), 0.1F);
 
         // invalid zero vector
         final List<Float> queryZeroVector = List.of(0.0f, 0.0f, 0.0f);