Ayush Chaurasia 3ffed89793 feat(python): Hybrid search & Reranker API (#824)
based on https://github.com/lancedb/lancedb/pull/713
- The Reranker api can be plugged into vector only or fts only search
but this PR doesn't do that (see example -
https://txt.cohere.com/rerank/)


### Default reranker -- `LinearCombinationReranker(weight=0.7,
fill=1.0)`

```
table.search("hello", query_type="hybrid").rerank(normalize="score").to_pandas()
```
### Available rerankers
LinearCombinationReranker
```
from lancedb.rerankers import LinearCombinationReranker

# Same as default 
table.search("hello", query_type="hybrid").rerank(
                                      normalize="score", 
                                      reranker=LinearCombinationReranker()
                                     ).to_pandas()

# with custom params
reranker = LinearCombinationReranker(weight=0.3, fill=1.0)
table.search("hello", query_type="hybrid").rerank(
                                      normalize="score", 
                                      reranker=reranker
                                     ).to_pandas()
```

Cohere Reranker
```
from lancedb.rerankers import CohereReranker

# default model.. English and multi-lingual supported. See docstring for available custom params
table.search("hello", query_type="hybrid").rerank(
                                      normalize="rank",  # score or rank
                                      reranker=CohereReranker()
                                     ).to_pandas()

```

CrossEncoderReranker

```
from lancedb.rerankers import CrossEncoderReranker

table.search("hello", query_type="hybrid").rerank(
                                      normalize="rank", 
                                      reranker=CrossEncoderReranker()
                                     ).to_pandas()

```

## Using custom Reranker
```
from lancedb.reranker import Reranker

class CustomReranker(Reranker):
    def rerank_hybrid(self, vector_result, fts_result):
           combined_res = self.merge_results(vector_results, fts_results) # or use custom combination logic
           # Custom rerank logic here
           
           return combined_res
```

- [x] Expand testing
- [x] Make sure usage makes sense
- [x] Run simple benchmarks for correctness (Seeing weird result from
cohere reranker in the toy example)
- Support diverse rerankers by default:
- [x] Cross encoding
- [x] Cohere
- [x] Reciprocal Rank Fusion

---------

Co-authored-by: Chang She <759245+changhiskhan@users.noreply.github.com>
Co-authored-by: Prashanth Rao <35005448+prrao87@users.noreply.github.com>
2024-01-30 19:10:33 +05:30
2024-01-26 22:40:36 +00:00
2023-03-17 18:15:19 -07:00
2023-12-08 20:55:04 +05:30

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Developer-friendly, serverless vector database for AI applications

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LanceDB Multimodal Search


LanceDB is an open-source database for vector-search built with persistent storage, which greatly simplifies retrevial, filtering and management of embeddings.

The key features of LanceDB include:

  • Production-scale vector search with no servers to manage.

  • Store, query and filter vectors, metadata and multi-modal data (text, images, videos, point clouds, and more).

  • Support for vector similarity search, full-text search and SQL.

  • Native Python and Javascript/Typescript support.

  • Zero-copy, automatic versioning, manage versions of your data without needing extra infrastructure.

  • GPU support in building vector index(*).

  • Ecosystem integrations with LangChain 🦜🔗, LlamaIndex 🦙, Apache-Arrow, Pandas, Polars, DuckDB and more on the way.

LanceDB's core is written in Rust 🦀 and is built using Lance, an open-source columnar format designed for performant ML workloads.

Quick Start

Javascript

npm install vectordb
const lancedb = require('vectordb');
const db = await lancedb.connect('data/sample-lancedb');

const table = await db.createTable('vectors',
      [{ id: 1, vector: [0.1, 0.2], item: "foo", price: 10 },
       { id: 2, vector: [1.1, 1.2], item: "bar", price: 50 }])

const query = table.search([0.1, 0.3]).limit(2);
const results = await query.execute();

Python

pip install lancedb
import lancedb

uri = "data/sample-lancedb"
db = lancedb.connect(uri)
table = db.create_table("my_table",
                         data=[{"vector": [3.1, 4.1], "item": "foo", "price": 10.0},
                               {"vector": [5.9, 26.5], "item": "bar", "price": 20.0}])
result = table.search([100, 100]).limit(2).to_pandas()

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