KGvec2go similarity functions.

dwslab · Aug 6, 2020 · 70d9cf7 · 70d9cf7
1 parent 91bb427
commit 70d9cf7
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diff --git a/...rc/main/java/de/uni_mannheim/informatik/dws/melt/matching_ml/kgvec2go/KGvec2goClient.java b/...rc/main/java/de/uni_mannheim/informatik/dws/melt/matching_ml/kgvec2go/KGvec2goClient.java
@@ -99,7 +99,18 @@ private void shutDown(){
     }
 
 
+    /**
+     * Receive a vector in the form of a double array.
+     * @param word Word for lookup.
+     * @param dataset Dataset for lookup.
+     * @return Null in case of failure, else vector.
+     */
     public Double[] getVector(String word, KGvec2goDatasets dataset){
+        // sanity check
+        if(word == null || dataset == null){
+            return null;
+        }
+
         // check buffer
         if(isInBuffer(word, dataset)){
             return getFromBuffer(word, dataset);
@@ -144,6 +155,18 @@ public Double[] getVector(String word, KGvec2goDatasets dataset){
     }
 
 
+    /**
+     *
+     * @param word1 Lookup word 1.
+     * @param word2 Lookup word 2.
+     * @param datasets Dataset to be used for lookup.
+     * @return Similarity.
+     */
+    public Double getSimilarity(String word1, String word2, KGvec2goDatasets datasets){
+        return cosineSimilarity(getVector(word1, datasets), getVector(word2, datasets));
+    }
+
+
     /**
      * Look in the cache whether a vector already exists for the given word in the given dataset.
      * @param word for which the vector shall be looked up.
@@ -184,4 +207,29 @@ private static void writeToBuffer(String word, KGvec2goDatasets dataset, Double[
         vectorCache.put(key, vector);
     }
 
+    /**
+     * Calculates the cosine similarity between two vectors.
+     * @param vector1 First vector.
+     * @param vector2 Second vector.
+     * @return Cosine similarity as double.
+     */
+    public static Double cosineSimilarity(Double[] vector1, Double[] vector2){
+        if(vector1 == null || vector2 == null){
+            return null;
+        }
+        if(vector1.length != vector2.length){
+            LOGGER.error("ERROR - the vectors must be of the same dimension.");
+            throw new ArithmeticException("The vectors must be of the same dimension");
+        }
+        double dotProduct = 0.0;
+        double norm1 = 0.0;
+        double norm2 = 0.0;
+        for (int i = 0; i < vector1.length; i++) {
+            dotProduct += vector1[i] * vector2[i];
+            norm1 = norm1 +  Math.pow(vector1[i], 2);
+            norm2 = norm2 + Math.pow(vector2[i], 2);
+        }
+        return dotProduct / ( Math.sqrt(norm1) * Math.sqrt(norm2) );
+    }
+
 }
diff --git a/...est/java/de/uni_mannheim/informatik/dws/melt/matching_ml/kgvec2go/KGvec2goClientTest.java b/...est/java/de/uni_mannheim/informatik/dws/melt/matching_ml/kgvec2go/KGvec2goClientTest.java
@@ -89,4 +89,59 @@ void getVector() {
         result = KGvec2goClient.getInstance().getVector("AABBCCDDEEFF", KGvec2goDatasets.WIKTIONARY);
         assertNull(result);
     }
+
+
+    @Test
+    void getSimilarity(){
+        KGvec2goClient kgvec2go = KGvec2goClient.getInstance();
+
+        // ---------
+        //   ALOD
+        // ---------
+
+        assertTrue(kgvec2go.getSimilarity("germany", "europe", KGvec2goDatasets.ALOD) > kgvec2go.getSimilarity("germany", "japan", KGvec2goDatasets.ALOD));
+        assertNull(kgvec2go.getSimilarity("usa", null, KGvec2goDatasets.ALOD));
+        assertNull(kgvec2go.getSimilarity(null, "usa", KGvec2goDatasets.ALOD));
+        assertNull(kgvec2go.getSimilarity("AAABBBCCC", "usa", KGvec2goDatasets.ALOD));
+
+        // ----------
+        //   DBpedia
+        // ----------
+
+        assertTrue(kgvec2go.getSimilarity("Germany", "Europe", KGvec2goDatasets.DBPEDIA) > kgvec2go.getSimilarity("Europe", "Japan", KGvec2goDatasets.DBPEDIA));
+        assertNull(kgvec2go.getSimilarity("USA", null, KGvec2goDatasets.ALOD));
+        assertNull(kgvec2go.getSimilarity(null, "USA", KGvec2goDatasets.ALOD));
+        assertNull(kgvec2go.getSimilarity("AAABBBCCC", "USA", KGvec2goDatasets.ALOD));
+
+        // ----------
+        //   WordNet
+        // ----------
+
+        assertTrue(kgvec2go.getSimilarity("Germany", "Europe", KGvec2goDatasets.WORDNET) > kgvec2go.getSimilarity("Europe", "Japan", KGvec2goDatasets.WORDNET));
+        assertNull(kgvec2go.getSimilarity("USA", null, KGvec2goDatasets.WORDNET));
+        assertNull(kgvec2go.getSimilarity(null, "USA", KGvec2goDatasets.WORDNET));
+        assertNull(kgvec2go.getSimilarity("AAABBBCCC", "USA", KGvec2goDatasets.WORDNET));
+
+
+        // --------------
+        //   Wiktionary
+        // --------------
+
+        assertTrue(kgvec2go.getSimilarity("Germany", "Europe", KGvec2goDatasets.WIKTIONARY) > kgvec2go.getSimilarity("Europe", "war", KGvec2goDatasets.WIKTIONARY));
+        assertNull(kgvec2go.getSimilarity("USA", null, KGvec2goDatasets.WIKTIONARY));
+        assertNull(kgvec2go.getSimilarity(null, "USA", KGvec2goDatasets.WIKTIONARY));
+        assertNull(kgvec2go.getSimilarity("AAABBBCCC", "USA", KGvec2goDatasets.WIKTIONARY));
+
+    }
+
+
+    @Test
+    void cosineSimilarity(){
+        Double[] v1 = {3d, 8d, 7d, 5d, 2d, 9d};
+        Double[] v2 = {10d, 8d, 6d, 6d, 4d, 5d};
+        Double[] v3 = {10d, 8d};
+
+        assertEquals(0.8639, KGvec2goClient.cosineSimilarity(v1, v2), 0.00001);
+        assertThrows(ArithmeticException.class, () -> KGvec2goClient.cosineSimilarity(v1, v3));
+    }
 }