Merge pull request #12 from Eigen-DB/handle_overwriting_of_vectors

Control how vectors are being overwritten

hnsw.go

@@ -199,6 +199,7 @@ func (i *Index) Free() {
 
 /*
 Adds a vector to the HNSW index.
+If the a vector with the same label already exists, the function returns an error
 
 - vector:       the vector to add to the index
 
@@ -211,13 +212,38 @@ func (i *Index) InsertVector(vector []float32, label uint64) error {
 		return fmt.Errorf("the vector you are trying to insert is %d-dimensional whereas your index is %d-dimensional", len(vector), i.dimensions)
 	}
 
+	_, err := i.GetVector(label)
+	if err == nil {
+		return fmt.Errorf("a vector with label %d already exists in the index", label)
+	}
+
 	if i.normalize {
 		Normalize(vector)
 	}
 	C.insertVector(i.index, (*C.float)(unsafe.Pointer(&vector[0])), C.ulong(label))
 	return getLastError()
 }
 
+/*
+Replaces an existing vector in the HNSW index.
+
+- label:        the vector's label
+
+- newVector:    the new vector used to replace the old vector
+
+Returns an error if one occured.
+*/
+func (i *Index) ReplaceVector(label uint64, newVector []float32) error {
+	if len(newVector) != i.dimensions {
+		return fmt.Errorf("the vector you are trying to insert is %d-dimensional whereas your index is %d-dimensional", len(newVector), i.dimensions)
+	}
+	if i.normalize {
+		Normalize(newVector)
+	}
+	C.insertVector(i.index, (*C.float)(unsafe.Pointer(&newVector[0])), C.ulong(label))
+	return getLastError()
+}
+
 /*
 Returns a vector's components using its label
 

hnsw_wrapper.cpp

@@ -78,7 +78,7 @@ HNSW loadHNSW(char *location, int dim, char spaceType, unsigned long maxElements
         } else { // default: L2
             vectorSpace = new hnswlib::L2Space(dim);
         }
-        return new hnswlib::HierarchicalNSW<float>(vectorSpace, std::string(location), false, maxElements); // load the index from the specified location
+        return new hnswlib::HierarchicalNSW<float>(vectorSpace, std::string(location), false, maxElements, true); // load the index from the specified location
     } catch (const std::runtime_error e) {
         lastErrorMsg = std::string(e.what());
         return nullptr;
@@ -112,7 +112,8 @@ void freeHNSW(HNSW hnswIndex) {
 }
 
 /**
- * Adds a vector to the HNSW index. If a vector with the specified label already exists, it will be overwritten.
+ * Adds a vector to the HNSW index. 
+ * NOTE: If a vector with the specified label already exists, IT WILL BE OVERWRITTEN.
  *
  * @param hnswIndex:    HNSW index to add the point to
  * @param vector:       the vector to add to the index

tests/hnswgo_test.go

@@ -132,8 +132,56 @@ func TestInsertVectorOverwrite(t *testing.T) {
 		t.Fatalf("An error occured when inserting a vector: %s", err.Error())
 	}
 
-	if err := index.InsertVector([]float32{4.2, 6.2}, 1); err != nil {
-		t.Fatalf("An error occured when overwritting vector: %s", err.Error())
+	if err := index.InsertVector([]float32{4.2, 6.2}, 1); err == nil {
+		t.Fatalf("No error occured when attempting to overwrite a vector")
+	} else if err.Error() != "a vector with label 1 already exists in the index" {
+		t.Fatalf("Got the wrong error when trying to overwrite a vector: %s", err.Error())
+	}
+}
+
+func TestReplaceVectorSuccess(t *testing.T) {
+	index, err := setup()
+	if err != nil {
+		t.Fatal(err.Error())
+	}
+	defer index.Free()
+
+	if err := index.InsertVector([]float32{1.2, -4.2}, 1); err != nil {
+		t.Fatalf("An error occured when inserting a vector: %s", err.Error())
+	}
+
+	if err := index.ReplaceVector(1, []float32{4.2, 6.2}); err != nil {
+		t.Fatalf("An error occured when trying to replace a vector: %s", err.Error())
+	}
+}
+
+func TestReplaceVectorFirstInsert(t *testing.T) {
+	index, err := setup()
+	if err != nil {
+		t.Fatal(err.Error())
+	}
+	defer index.Free()
+
+	if err := index.ReplaceVector(1, []float32{4.2, 6.2}); err != nil {
+		t.Fatalf("An error occured when trying to replace a non-existant vector: %s", err.Error())
+	}
+}
+
+func TestReplaceVectorInvalidDims(t *testing.T) {
+	index, err := setup()
+	if err != nil {
+		t.Fatal(err.Error())
+	}
+	defer index.Free()
+
+	if err := index.InsertVector([]float32{1.2, -4.2}, 1); err != nil {
+		t.Fatalf("An error occured when inserting a vector: %s", err.Error())
+	}
+
+	if err := index.ReplaceVector(1, []float32{4.2, 6.2, 3.3}); err == nil {
+		t.Fatalf("No error occured when trying to replace a vector with invalid dimensions")
+	} else if err.Error() != "the vector you are trying to insert is 3-dimensional whereas your index is 2-dimensional" {
+		t.Fatalf("Got the wrong error when trying to overwrite a vector with invalid dimensions: %s", err.Error())
 	}
 }