Harrison/new search (#4359)

Co-authored-by: Jiaping(JP) Zhang <vincentzhangv@gmail.com>

docs/modules/indexes/retrievers/examples/vectorstore-retriever.ipynb

@@ -25,18 +25,10 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 9,
+   "execution_count": 2,
    "id": "9fbcc58f",
    "metadata": {},
-   "outputs": [
-    {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "Exiting: Cleaning up .chroma directory\n"
-     ]
-    }
-   ],
+   "outputs": [],
    "source": [
     "from langchain.text_splitter import CharacterTextSplitter\n",
     "from langchain.vectorstores import FAISS\n",
@@ -74,6 +66,7 @@
    "id": "79b783de",
    "metadata": {},
    "source": [
+    "## Maximum Marginal Relevance Retrieval\n",
     "By default, the vectorstore retriever uses similarity search. If the underlying vectorstore support maximum marginal relevance search, you can specify that as the search type."
    ]
   },
@@ -97,11 +90,42 @@
     "docs = retriever.get_relevant_documents(\"what did he say abotu ketanji brown jackson\")"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "id": "2d958271",
+   "metadata": {},
+   "source": [
+    "## Similarity Score Threshold Retrieval\n",
+    "\n",
+    "You can also a retrieval method that sets a similarity score threshold and only returns documents with a score above that threshold"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "id": "d4272ad8",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "retriever = db.as_retriever(search_type=\"similarity_score_threshold\", search_kwargs={\"score_threshold\": .5})"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "id": "438e761d",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "docs = retriever.get_relevant_documents(\"what did he say abotu ketanji brown jackson\")"
+   ]
+  },
   {
    "cell_type": "markdown",
    "id": "c23b7698",
    "metadata": {},
    "source": [
+    "## Specifying top k\n",
     "You can also specify search kwargs like `k` to use when doing retrieval."
    ]
   },
@@ -171,7 +195,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.11.3"
+   "version": "3.9.1"
   }
  },
  "nbformat": 4,