Don't normalize user supplied vectors in place

Except for in AddDocument as the caller hands of control of the Document
to us there.

collection.go

@@ -225,7 +225,7 @@ func (c *Collection) AddDocument(ctx context.Context, doc Document) error {
 		doc.Embedding = embedding
 	} else {
 		if !isNormalized(doc.Embedding) {
-			normalizeVector(doc.Embedding)
+			normalizeVectorInPlace(doc.Embedding)
 		}
 	}
 
@@ -388,7 +388,7 @@ func (c *Collection) QueryEmbedding(ctx context.Context, queryEmbedding []float3
 	// Normalize embedding if not the case yet. We only support cosine similarity
 	// for now and all documents were already normalized when added to the collection.
 	if !isNormalized(queryEmbedding) {
-		normalizeVector(queryEmbedding)
+		queryEmbedding = normalizeVector(queryEmbedding)
 	}
 
 	// If the filtering already reduced the number of documents to fewer than nResults,

collection_test.go

@@ -567,7 +567,7 @@ func benchmarkCollection_Query(b *testing.B, n int, withContent bool) {
 		qv[j] = r.Float32()
 	}
 	// The document embeddings are normalized, so the query must be normalized too.
-	normalizeVector(qv)
+	normalizeVectorInPlace(qv)
 
 	// Create collection
 	db := NewDB()
@@ -590,7 +590,7 @@ func benchmarkCollection_Query(b *testing.B, n int, withContent bool) {
 		for j := 0; j < d; j++ {
 			v[j] = r.Float32()
 		}
-		normalizeVector(v)
+		normalizeVectorInPlace(v)
 
 		// Add document with some metadata and content depending on parameter.
 		// When providing embeddings, the embedding func is not called.

embed_cohere.go

@@ -159,7 +159,7 @@ func NewEmbeddingFuncCohere(apiKey string, model EmbeddingModelCohere) Embedding
 			}
 		})
 		if !checkedNormalized {
-			normalizeVector(v)
+			normalizeVectorInPlace(v)
 		}
 
 		return v, nil

embed_ollama.go

@@ -91,7 +91,7 @@ func NewEmbeddingFuncOllama(model string, baseURLOllama string) EmbeddingFunc {
 			}
 		})
 		if !checkedNormalized {
-			normalizeVector(v)
+			normalizeVectorInPlace(v)
 		}
 
 		return v, nil

embed_openai.go

@@ -142,7 +142,7 @@ func newEmbeddingFuncOpenAICompat(baseURL, apiKey, model string, normalized *boo
 			if *normalized {
 				return v, nil
 			}
-			normalizeVector(v)
+			normalizeVectorInPlace(v)
 			return v, nil
 		}
 		checkNormalized.Do(func() {
@@ -153,7 +153,7 @@ func newEmbeddingFuncOpenAICompat(baseURL, apiKey, model string, normalized *boo
 			}
 		})
 		if !checkedNormalized {
-			normalizeVector(v)
+			normalizeVectorInPlace(v)
 		}
 
 		return v, nil

vector.go

@@ -19,8 +19,8 @@ func cosineSimilarity(a, b []float32) (float32, error) {
 	}
 
 	if !isNormalized(a) || !isNormalized(b) {
-		normalizeVector(a)
-		normalizeVector(b)
+		a = normalizeVector(a)
+		b = normalizeVector(b)
 	}
 	dotProduct, err := dotProduct(a, b)
 	if err != nil {
@@ -50,7 +50,7 @@ func dotProduct(a, b []float32) (float32, error) {
 	return dotProduct, nil
 }
 
-func normalizeVector(v []float32) {
+func normalizeVectorInPlace(v []float32) {
 	var norm float32
 	for _, val := range v {
 		norm += val * val
@@ -62,6 +62,13 @@ func normalizeVector(v []float32) {
 	}
 }
 
+func normalizeVector(v []float32) []float32 {
+	r := make([]float32, len(v))
+	copy(r, v)
+	normalizeVectorInPlace(r)
+	return r
+}
+
 // isNormalized checks if the vector is normalized.
 func isNormalized(v []float32) bool {
 	var sqSum float64