使用 Cohere Rerank 重排序搜索结果
一个重排序管道可以对搜索结果进行重排序，为搜索结果中的每个文档提供相对于搜索查询的相关性分数。相关性分数由交叉编码器模型计算。
本教程将向您展示如何在重排序管道中使用 Cohere Rerank 模型。
将以 your_ 为前缀的占位符替换为您自己的值。
步骤 1：注册 Cohere Rerank 模型
为 Cohere Rerank 模型创建连接器
POST /_plugins/_ml/connectors/_create
{
"name": "cohere-rerank",
"description": "The connector to Cohere reanker model",
"version": "1",
"protocol": "http",
"credential": {
"cohere_key": "your_cohere_api_key"
},
"parameters": {
"model": "rerank-english-v2.0"
},
"actions": [
{
"action_type": "predict",
"method": "POST",
"url": "https://api.cohere.ai/v1/rerank",
"headers": {
"Authorization": "Bearer ${credential.cohere_key}"
},
"request_body": "{ \"documents\": ${parameters.documents}, \"query\": \"${parameters.query}\", \"model\": \"${parameters.model}\", \"top_n\": ${parameters.top_n} }",
"pre_process_function": "connector.pre_process.cohere.rerank",
"post_process_function": "connector.post_process.cohere.rerank"
}
]
}
使用响应中的连接器 ID 注册 Cohere Rerank 模型
POST /_plugins/_ml/models/_register?deploy=true
{
"name": "cohere rerank model",
"function_name": "remote",
"description": "test rerank model",
"connector_id": "your_connector_id"
}
记下响应中的模型 ID；您将在后续步骤中使用它。
通过调用预测 API 测试模型
POST _plugins/_ml/models/your_model_id/_predict
{
"parameters": {
"query": "What is the capital of the United States?",
"documents": [
"Carson City is the capital city of the American state of Nevada.",
"The Commonwealth of the Northern Mariana Islands is a group of islands in the Pacific Ocean. Its capital is Saipan.",
"Washington, D.C. (also known as simply Washington or D.C., and officially as the District of Columbia) is the capital of the United States. It is a federal district.",
"Capital punishment (the death penalty) has existed in the United States since beforethe United States was a country. As of 2017, capital punishment is legal in 30 of the 50 states."
],
"top_n": 4
}
}
为确保与重排序管道的兼容性，top_n 值必须与 documents 列表的长度相同。
您可以通过提供 size 参数来自定义响应中返回的顶部文档数量。有关更多信息，请参阅 步骤 2.3。
OpenSearch 返回推理结果
{
"inference_results": [
{
"output": [
{
"name": "similarity",
"data_type": "FLOAT32",
"shape": [
1
],
"data": [
0.10194652
]
},
{
"name": "similarity",
"data_type": "FLOAT32",
"shape": [
1
],
"data": [
0.0721122
]
},
{
"name": "similarity",
"data_type": "FLOAT32",
"shape": [
1
],
"data": [
0.98005307
]
},
{
"name": "similarity",
"data_type": "FLOAT32",
"shape": [
1
],
"data": [
0.27904198
]
}
],
"status_code": 200
}
]
}
响应包含四个 similarity 对象。对于每个 similarity 对象，data 数组包含每个文档相对于查询的相关性分数。similarity 对象按照输入文档的顺序提供；第一个对象对应第一个文档。这与 Cohere Rerank 模型的默认输出不同，默认输出按相关性分数对文档进行排序。文档顺序在 connector.post_process.cohere.rerank 后处理函数中进行了更改，以使输出与重排序管道兼容。
步骤 2：配置重排序管道
请按照以下步骤配置重排序管道。
步骤 2.1：摄取测试数据
发送批量请求摄入测试数据
POST _bulk
{ "index": { "_index": "my-test-data" } }
{ "passage_text" : "Carson City is the capital city of the American state of Nevada." }
{ "index": { "_index": "my-test-data" } }
{ "passage_text" : "The Commonwealth of the Northern Mariana Islands is a group of islands in the Pacific Ocean. Its capital is Saipan." }
{ "index": { "_index": "my-test-data" } }
{ "passage_text" : "Washington, D.C. (also known as simply Washington or D.C., and officially as the District of Columbia) is the capital of the United States. It is a federal district." }
{ "index": { "_index": "my-test-data" } }
{ "passage_text" : "Capital punishment (the death penalty) has existed in the United States since beforethe United States was a country. As of 2017, capital punishment is legal in 30 of the 50 states." }
步骤 2.2：创建重新排序管道
使用 Cohere Rerank 模型创建重排序管道
PUT /_search/pipeline/rerank_pipeline_cohere
{
"description": "Pipeline for reranking with Cohere Rerank model",
"response_processors": [
{
"rerank": {
"ml_opensearch": {
"model_id": "your_model_id_created_in_step1"
},
"context": {
"document_fields": ["passage_text"]
}
}
}
]
}
步骤 2.3：测试重排序
要限制返回结果的数量，您可以指定 size 参数。例如，设置 "size": 2 以返回前两个文档
GET my-test-data/_search?search_pipeline=rerank_pipeline_cohere
{
"query": {
"match_all": {}
},
"size": 4,
"ext": {
"rerank": {
"query_context": {
"query_text": "What is the capital of the United States?"
}
}
}
}
响应包含两个最相关的文档
{
"took": 0,
"timed_out": false,
"_shards": {
"total": 1,
"successful": 1,
"skipped": 0,
"failed": 0
},
"hits": {
"total": {
"value": 4,
"relation": "eq"
},
"max_score": 0.98005307,
"hits": [
{
"_index": "my-test-data",
"_id": "zbUOw40B8vrNLhb9vBif",
"_score": 0.98005307,
"_source": {
"passage_text": "Washington, D.C. (also known as simply Washington or D.C., and officially as the District of Columbia) is the capital of the United States. It is a federal district."
}
},
{
"_index": "my-test-data",
"_id": "zrUOw40B8vrNLhb9vBif",
"_score": 0.27904198,
"_source": {
"passage_text": "Capital punishment (the death penalty) has existed in the United States since beforethe United States was a country. As of 2017, capital punishment is legal in 30 of the 50 states."
}
},
{
"_index": "my-test-data",
"_id": "y7UOw40B8vrNLhb9vBif",
"_score": 0.10194652,
"_source": {
"passage_text": "Carson City is the capital city of the American state of Nevada."
}
},
{
"_index": "my-test-data",
"_id": "zLUOw40B8vrNLhb9vBif",
"_score": 0.0721122,
"_source": {
"passage_text": "The Commonwealth of the Northern Mariana Islands is a group of islands in the Pacific Ocean. Its capital is Saipan."
}
}
]
},
"profile": {
"shards": []
}
}
要将这些结果与不进行重排序的结果进行比较，请在没有重排序管道的情况下运行搜索
GET my-test-data/_search
{
"query": {
"match_all": {}
},
"ext": {
"rerank": {
"query_context": {
"query_text": "What is the capital of the United States?"
}
}
}
}
响应中的第一个文档与卡森城有关，而卡森城并非美国首都
{
"took": 0,
"timed_out": false,
"_shards": {
"total": 1,
"successful": 1,
"skipped": 0,
"failed": 0
},
"hits": {
"total": {
"value": 4,
"relation": "eq"
},
"max_score": 1,
"hits": [
{
"_index": "my-test-data",
"_id": "y7UOw40B8vrNLhb9vBif",
"_score": 1,
"_source": {
"passage_text": "Carson City is the capital city of the American state of Nevada."
}
},
{
"_index": "my-test-data",
"_id": "zLUOw40B8vrNLhb9vBif",
"_score": 1,
"_source": {
"passage_text": "The Commonwealth of the Northern Mariana Islands is a group of islands in the Pacific Ocean. Its capital is Saipan."
}
},
{
"_index": "my-test-data",
"_id": "zbUOw40B8vrNLhb9vBif",
"_score": 1,
"_source": {
"passage_text": "Washington, D.C. (also known as simply Washington or D.C., and officially as the District of Columbia) is the capital of the United States. It is a federal district."
}
},
{
"_index": "my-test-data",
"_id": "zrUOw40B8vrNLhb9vBif",
"_score": 1,
"_source": {
"passage_text": "Capital punishment (the death penalty) has existed in the United States since beforethe United States was a country. As of 2017, capital punishment is legal in 30 of the 50 states."
}
}
]
}
}