add tutorial for semantic search with byte quantized vector and Cohere embedding model

docs/tutorials/semantic_search/conversation_search_with_byte_quantized_vector.md

@@ -0,0 +1,278 @@
+# Topic
+
+> This tutorial doesn't explain details about byte-quantized vectors. Read this [Byte-quantized vectors in OpenSearch](https://opensearch.org/blog/byte-quantized-vectors-in-opensearch/) to learn more details.
+
+This tutorial explains how to build semantic search with [Cohere Embedding model](https://docs.cohere.com/reference/embed) and byte-quantized vectors in OpenSearch.
+
+Cohere embedding model v3 supports more `embedding_types`, this tutorial uses `"int8"` to work with byte-quantized vectors.
+
+Note: Replace the placeholders that start with `your_` with your own values.
+
+# Steps
+
+Cohere embedding model v3 supports different `input_type`. From Cohere [doc](https://docs.cohere.com/reference/embed)
+> - `"search_document"`: Used for embeddings stored in a vector database for search use-cases.
+> - `"search_query"`: Used for embeddings of search queries run against a vector DB to find relevant documents.
+
+We will create two models in this tutorial:
+- one model with `search_document` input type for ingestion
+- one model with `search_query` input type for search
+
+## 1. Create embedding model for ingestion
+
+Create connector with `search_document` input type
+
+```
+POST /_plugins/_ml/connectors/_create
+{
+    "name": "Cohere embedding connector with int8 embedding type for ingestion",
+    "description": "Test connector for Cohere embedding model",
+    "version": 1,
+    "protocol": "http",
+    "credential": {
+        "cohere_key": "your_cohere_api_key"
+    },
+    "parameters": {
+        "model": "embed-english-v3.0",
+        "embedding_types": ["int8"],
+        "input_type": "search_document"
+    },
+    "actions": [
+        {
+            "action_type": "predict",
+            "method": "POST",
+            "headers": {
+                "Authorization": "Bearer ${credential.cohere_key}",
+                "Request-Source": "unspecified:opensearch"
+            },
+            "url": "https://api.cohere.ai/v1/embed",
+            "request_body": "{ \"model\": \"${parameters.model}\", \"texts\": ${parameters.texts}, \"input_type\":\"${parameters.input_type}\", \"embedding_types\": ${parameters.embedding_types} }",
+            "pre_process_function": "connector.pre_process.cohere.embedding",
+            "post_process_function": "\n    def name = \"sentence_embedding\";\n    def data_type = \"FLOAT32\";\n    def result;\n    if (params.embeddings.int8 != null) {\n      data_type = \"INT8\";\n      result = params.embeddings.int8;\n    } else if (params.embeddings.uint8 != null) {\n      data_type = \"UINT8\";\n      result = params.embeddings.uint8;\n    } else if (params.embeddings.float != null) {\n      data_type = \"FLOAT32\";\n      result = params.embeddings.float;\n    }\n    \n    if (result == null) {\n      return \"Invalid embedding result\";\n    }\n    \n    def embedding_list = new StringBuilder(\"[\");\n    \n    for (int m=0; m<result.length; m++) {\n      def embedding_size = result[m].length;\n      def embedding = new StringBuilder(\"[\");\n      def shape = [embedding_size];\n      for (int i=0; i<embedding_size; i++) {\n        def val;\n        if (\"FLOAT32\".equals(data_type)) {\n          val = result[m][i].floatValue();\n        } else if (\"INT8\".equals(data_type) || \"UINT8\".equals(data_type)) {\n          val = result[m][i].intValue();\n        }\n        embedding.append(val);\n        if (i < embedding_size - 1) {\n          embedding.append(\",\");  \n        }\n      }\n      embedding.append(\"]\");  \n      \n      // workaround for compatible with neural-search\n      def dummy_data_type = 'FLOAT32';\n      \n      def json = '{' +\n                   '\"name\":\"' + name + '\",' +\n                   '\"data_type\":\"' + dummy_data_type + '\",' +\n                   '\"shape\":' + shape + ',' +\n                   '\"data\":' + embedding +\n                   '}';\n      embedding_list.append(json);\n      if (m < result.length - 1) {\n        embedding_list.append(\",\");  \n      }\n    }\n    embedding_list.append(\"]\");  \n    return embedding_list.toString();\n    "
+        }
+    ]
+}
+```
+Use connector id from the response to create model
+```
+POST /_plugins/_ml/models/_register?deploy=true
+{
+    "name": "Cohere embedding model for INT8 with search_document input type",
+    "function_name": "remote",
+    "description": "test model",
+    "connector_id": "your_connector_id"
+}
+```
+Note the model id, it will be used in step 2.1
+
+Test model
+```
+POST /_plugins/_ml/models/your_embedding_model_id/_predict
+{
+    "parameters": {
+        "texts": ["hello", "goodbye"]
+    }
+}
+```
+Sample response
+
+```
+{
+    "inference_results": [
+        {
+            "output": [
+                {
+                    "name": "sentence_embedding",
+                    "data_type": "FLOAT32",
+                    "shape": [
+                        1024
+                    ],
+                    "data": [
+                        20,
+                        -11,
+                        -60,
+                        -91,
+                        ...
+                    ]
+                },
+                {
+                    "name": "sentence_embedding",
+                    "data_type": "FLOAT32",
+                    "shape": [
+                        1024
+                    ],
+                    "data": [
+                        58,
+                        -30,
+                        9,
+                        -51,
+                        ...
+                    ]
+                }
+            ],
+            "status_code": 200
+        }
+    ]
+}
+```
+
+## 2. Ingest data
+
+### 2.1 Create ingest pipeline
+
+```
+PUT /_ingest/pipeline/pipeline-cohere
+{
+  "description": "Cohere embedding ingest pipeline",
+  "processors": [
+    {
+      "text_embedding": {
+        "model_id": "your_embedding_model_id_created_in_step1",
+        "field_map": {
+          "passage_text": "passage_embedding"
+        }
+      }
+    }
+  ]
+}
+```
+
+### 2.2 Create KNN index with byte-quantized vector
+Refer to https://opensearch.org/blog/byte-quantized-vectors-in-opensearch/
+
+```
+PUT my_test_data
+{
+  "settings": {
+    "index": {
+      "knn": true,
+      "knn.algo_param.ef_search": 100,
+      "default_pipeline": "pipeline-cohere"
+    }
+  },
+  "mappings": {
+    "properties": {
+      "passage_text": {
+        "type": "text"
+      },
+      "passage_embedding": {
+        "type": "knn_vector",
+        "dimension": 1024,
+        "data_type": "byte",
+        "method": {
+          "name": "hnsw",
+          "space_type": "l2",
+          "engine": "lucene",
+          "parameters": {
+            "ef_construction": 128,
+            "m": 24
+          }
+        }
+      }
+    }
+  }
+}
+```
+
+Ingest test data
+
+```
+POST _bulk
+{ "index" : { "_index" : "my_test_data" } }
+{ "passage_text" : "OpenSearch is the flexible, scalable, open-source way to build solutions for data-intensive applications. Explore, enrich, and visualize your data with built-in performance, developer-friendly tools, and powerful integrations for machine learning, data processing, and more." }
+{ "index" : { "_index" : "my_test_data"} }
+{ "passage_text" : "BM25 is a keyword-based algorithm that performs well on queries containing keywords but fails to capture the semantic meaning of the query terms. Semantic search, unlike keyword-based search, takes into account the meaning of the query in the search context. Thus, semantic search performs well when a query requires natural language understanding." }
+
+```
+
+## 3. Semantic search
+
+Let's create another embedding model with `search_query` input type
+```
+POST /_plugins/_ml/connectors/_create
+{
+    "name": "Cohere embedding connector with int8 embedding type for search",
+    "description": "Test connector for Cohere embedding model. Use this connector for search.",
+    "version": 1,
+    "protocol": "http",
+    "credential": {
+        "cohere_key": "your_cohere_api_key"
+    },
+    "parameters": {
+        "model": "embed-english-v3.0",
+        "embedding_types": ["int8"],
+        "input_type": "search_query"
+    },
+    "actions": [
+        {
+            "action_type": "predict",
+            "method": "POST",
+            "headers": {
+                "Authorization": "Bearer ${credential.cohere_key}",
+                "Request-Source": "unspecified:opensearch"
+            },
+            "url": "https://api.cohere.ai/v1/embed",
+            "request_body": "{ \"model\": \"${parameters.model}\", \"texts\": ${parameters.texts}, \"input_type\":\"${parameters.input_type}\", \"embedding_types\": ${parameters.embedding_types} }",
+            "pre_process_function": "connector.pre_process.cohere.embedding",
+            "post_process_function": "\n    def name = \"sentence_embedding\";\n    def data_type = \"FLOAT32\";\n    def result;\n    if (params.embeddings.int8 != null) {\n      data_type = \"INT8\";\n      result = params.embeddings.int8;\n    } else if (params.embeddings.uint8 != null) {\n      data_type = \"UINT8\";\n      result = params.embeddings.uint8;\n    } else if (params.embeddings.float != null) {\n      data_type = \"FLOAT32\";\n      result = params.embeddings.float;\n    }\n    \n    if (result == null) {\n      return \"Invalid embedding result\";\n    }\n    \n    def embedding_list = new StringBuilder(\"[\");\n    \n    for (int m=0; m<result.length; m++) {\n      def embedding_size = result[m].length;\n      def embedding = new StringBuilder(\"[\");\n      def shape = [embedding_size];\n      for (int i=0; i<embedding_size; i++) {\n        def val;\n        if (\"FLOAT32\".equals(data_type)) {\n          val = result[m][i].floatValue();\n        } else if (\"INT8\".equals(data_type) || \"UINT8\".equals(data_type)) {\n          val = result[m][i].intValue();\n        }\n        embedding.append(val);\n        if (i < embedding_size - 1) {\n          embedding.append(\",\");  \n        }\n      }\n      embedding.append(\"]\");  \n      \n      // workaround for compatible with neural-search\n      def dummy_data_type = 'FLOAT32';\n      \n      def json = '{' +\n                   '\"name\":\"' + name + '\",' +\n                   '\"data_type\":\"' + dummy_data_type + '\",' +\n                   '\"shape\":' + shape + ',' +\n                   '\"data\":' + embedding +\n                   '}';\n      embedding_list.append(json);\n      if (m < result.length - 1) {\n        embedding_list.append(\",\");  \n      }\n    }\n    embedding_list.append(\"]\");  \n    return embedding_list.toString();\n    "
+        }
+    ]
+}
+```
+Use the connector id from response to create model
+```
+POST /_plugins/_ml/models/_register?deploy=true
+{
+    "name": "Cohere embedding model for INT8 with search_document input type",
+    "function_name": "remote",
+    "description": "test model",
+    "connector_id": "your_connector_id"
+}
+```
+Then you can use the model id from response to run neural search query:
+```
+POST /my_test_data/_search
+{
+  "query": {
+    "neural": {
+      "passage_embedding": {
+        "query_text": "semantic search",
+        "model_id": "your_embedding_model_id",
+        "k": 100
+      }
+    }
+  },
+  "size": "1",
+  "_source": ["passage_text"]
+}
+```
+Sample response
+```
+{
+  "took": 143,
+  "timed_out": false,
+  "_shards": {
+    "total": 1,
+    "successful": 1,
+    "skipped": 0,
+    "failed": 0
+  },
+  "hits": {
+    "total": {
+      "value": 2,
+      "relation": "eq"
+    },
+    "max_score": 9.345969e-7,
+    "hits": [
+      {
+        "_index": "my_test_data",
+        "_id": "_IXCuY0BJr_OiKWden7i",
+        "_score": 9.345969e-7,
+        "_source": {
+          "passage_text": "BM25 is a keyword-based algorithm that performs well on queries containing keywords but fails to capture the semantic meaning of the query terms. Semantic search, unlike keyword-based search, takes into account the meaning of the query in the search context. Thus, semantic search performs well when a query requires natural language understanding."
+        }
+      }
+    ]
+  }
+}
+```