Harrison/elastic search (#2419)

docs/modules/indexes/retrievers/examples/elastic_search_bm25.ipynb

@@ -0,0 +1,164 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "id": "ab66dd43",
+   "metadata": {},
+   "source": [
+    "# ElasticSearch BM25\n",
+    "\n",
+    "This notebook goes over how to use a retriever that under the hood uses ElasticSearcha and BM25.\n",
+    "\n",
+    "For more information on the details of BM25 see [this blog post](https://www.elastic.co/blog/practical-bm25-part-2-the-bm25-algorithm-and-its-variables)."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "id": "393ac030",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "from langchain.retrievers import ElasticSearchBM25Retriever"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "aaf80e7f",
+   "metadata": {},
+   "source": [
+    "## Create New Retriever"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 12,
+   "id": "bcb3c8c2",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "elasticsearch_url=\"http://localhost:9200\"\n",
+    "retriever = ElasticSearchBM25Retriever.create(elasticsearch_url, \"langchain-index-3\")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 13,
+   "id": "b605284d",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# Alternatively, you can load an existing index\n",
+    "# import elasticsearch\n",
+    "# elasticsearch_url=\"http://localhost:9200\"\n",
+    "# retriever = ElasticSearchBM25Retriever(elasticsearch.Elasticsearch(elasticsearch_url), \"langchain-index\")"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "1c518c42",
+   "metadata": {},
+   "source": [
+    "## Add texts (if necessary)\n",
+    "\n",
+    "We can optionally add texts to the retriever (if they aren't already in there)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 14,
+   "id": "98b1c017",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "['386c76c9-4355-4c12-aaeb-7b80054caf93',\n",
+       " 'fffd279c-a0c9-4158-a904-6e242c517c99',\n",
+       " '7f5528a3-18d0-43b0-894d-f6770a002219',\n",
+       " 'e2ef5e32-d5bd-44e2-b045-cfc5a8e0a0a1',\n",
+       " 'cce8ba48-e473-4235-bca2-2c8d65e73ccf']"
+      ]
+     },
+     "execution_count": 14,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "retriever.add_texts([\"foo\", \"bar\", \"world\", \"hello\", \"foo bar\"])"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "08437fa2",
+   "metadata": {},
+   "source": [
+    "## Use Retriever\n",
+    "\n",
+    "We can now use the retriever!"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 15,
+   "id": "c0455218",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "result = retriever.get_relevant_documents(\"foo\")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 16,
+   "id": "7dfa5c29",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[Document(page_content='foo', metadata={}),\n",
+       " Document(page_content='foo bar', metadata={})]"
+      ]
+     },
+     "execution_count": 16,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "result"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "74bd9256",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3 (ipykernel)",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.9.1"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}