TutorialsOfficial documentation8 min readTutorials

Explain FastGPT Dataset Result Ranking and Fusion

Multi-Path Recall Architecture FastGPT’s dataset search system does not rely on a single recall pathway to retrieve relevant content.

Multi-Path Recall Architecture

FastGPT’s dataset search system does not rely on a single recall pathway to retrieve relevant content. Instead, it aggregates results from multiple standardized recall paths to cover a wider range of query types and use cases. The most common recall paths include text vector recall, full-text recall, image description recall, image vector recall, and pre-reranked results.

Recall PathCore MechanismIdeal Use Cases
Semantic SearchVector similarity matchingNatural-language questions, semantically related dataset content
Full-Text SearchExact keyword matchingIDs, model numbers, proper nouns, error codes, exact string queries
Hybrid SearchCombines semantic + full-text recall, merges via RRFBalanced query types requiring both contextual relevance and exact matches
RerankRe-sorts candidate text resultsClearly defined user questions with a sufficient volume of candidate results
Image SearchUses image description or vector embeddingsDataset content paired with visual assets, requires cross-modal result fusion

Hybrid and Rerank Fusion Logic

Hybrid search combines outputs from both semantic search and full-text search, then merges the combined candidate set using Reciprocal Rank Fusion (RRF). The rerank step takes the unified hybrid candidate set and re-sorts the text-based results, which delivers optimal performance when the user’s question is clearly articulated and a sufficient number of candidate results are available for reordering.

Final Result Ranking Rules

Unlike single-path search systems, FastGPT’s final ranked cited content does not follow a strict order based solely on a single vector similarity score. Instead, content that is matched by multiple recall pathways will typically receive a higher final rank. This multi-path validation ensures that more relevant, cross-validated cited content is prioritized for user queries, reducing the risk of irrelevant results from a single flawed recall pathway.

Cross-Modal Image Fusion

For dataset collections that include visual assets, FastGPT integrates image search results into the overall ranking and fusion pipeline. Image search generates results using either image description embeddings or raw image vector embeddings, then fuses these image-derived results with the text-side recall results to create a complete, cross-modal candidate set for final ranking.

Source: FastGPT official source

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