Added separate interface for creating and writing in a faiss index

Final commit for building graphs iteratively

Signed-off-by: Navneet Verma <navneev@amazon.com>

jni/include/faiss_wrapper.h

@@ -22,6 +22,13 @@ namespace knn_jni {
         void CreateIndex(knn_jni::JNIUtilInterface * jniUtil, JNIEnv * env, jintArray idsJ, jlong vectorsAddressJ, jint dimJ,
                          jstring indexPathJ, jobject parametersJ);
 
+        // Create an index with ids and vectors. The configuration is defined by values in the Java map, parametersJ.
+        // The index is serialized to indexPathJ.
+        long long CreateIndexIteratively(knn_jni::JNIUtilInterface * jniUtil, JNIEnv * env, jintArray idsJ, jlong vectorsAddressJ, jint dimJ,
+                         jlong indexAddressJ, jobject parametersJ);
+
+        void writeIndex(knn_jni::JNIUtilInterface * jniUtil, JNIEnv * env,jlong indexAddressJ, jstring indexPathJ, jobject parametersJ);
+
         // Create an index with ids and vectors. Instead of creating a new index, this function creates the index
         // based off of the template index passed in. The index is serialized to indexPathJ.
         void CreateIndexFromTemplate(knn_jni::JNIUtilInterface * jniUtil, JNIEnv * env, jintArray idsJ,

jni/include/org_opensearch_knn_jni_FaissService.h

@@ -26,6 +26,23 @@ extern "C" {
 JNIEXPORT void JNICALL Java_org_opensearch_knn_jni_FaissService_createIndex
         (JNIEnv *, jclass, jintArray, jlong, jint, jstring, jobject);
 
+/*
+ * Class:     org_opensearch_knn_jni_FaissService
+ * Method:    createIndexIteratively
+ * Signature: ([IJIJLjava/util/Map;)J
+ */
+JNIEXPORT jlong JNICALL Java_org_opensearch_knn_jni_FaissService_createIndexIteratively
+  (JNIEnv *, jclass, jintArray, jlong, jint, jlong, jobject);
+
+/*
+ * Class:     org_opensearch_knn_jni_FaissService
+ * Method:    writeIndex
+ * Signature: (JLjava/lang/String;Ljava/util/Map;)V
+ */
+JNIEXPORT void JNICALL Java_org_opensearch_knn_jni_FaissService_writeIndex
+  (JNIEnv *, jclass, jlong, jstring, jobject);
+
+
 /*
  * Class:     org_opensearch_knn_jni_FaissService
  * Method:    createIndexFromTemplate