retrieval-patternslisted
Install: claude install-skill homecity/langchain-forum
# Retrieval Patterns SKILL
## 1. Hybrid Search (BM25 + Semantic)
```python
from langchain.retrievers import EnsembleRetriever
ensemble = EnsembleRetriever(
retrievers=[bm25_retriever, semantic_retriever],
weights=[0.5, 0.5]
)
```
## 2. MMR (Maximal Marginal Relevance)
```python
retriever = vector_store.as_retriever(
search_type="mmr",
search_kwargs={"k": 5, "lambda_mult": 0.5}
)
```
## 3. Cross-Encoder Reranking
```python
from langchain.retrievers.document_compressors import CrossEncoderReranker
compressor = CrossEncoderReranker(
model_name="cross-encoder/ms-marco-MiniLM-L-6-v2"
)
```