src/retrieval/README.md

Retrieval Module

FAISS-based similarity search with modality filtering.

Files

File	Description
index.py	FAISS index operations (build, search, save/load)
engine.py	Retrieval engine
multimodal.py	Multi-modal retrieval with same-modal and cross-modal queries

Index Type

Parameter	Value
Type	IndexFlatIP
Similarity	Inner Product (Cosine on L2-normalized vectors)
Build Time	O(N)
Search Time	O(N)

Usage

from src.retrieval.multimodal import MultiModalRetrieval

# Initialize
retrieval = MultiModalRetrieval(embed_dim=768)

# Build index from modality embeddings
retrieval.build_index({
    "optical": optical_embeddings,
    "sar": sar_embeddings,
    "multispectral": ms_embeddings,
})

# Same-modal query
result = retrieval.same_modal_query(query, modality="optical", k=5)

# Cross-modal query
result = retrieval.cross_modal_query(
    query, source_modality="optical", target_modality="sar", k=5
)