/**
 * Semantic Hasher - TF-IDF + Cosine Similarity
 *
 * Provides fast duplicate detection and semantic similarity scoring
 */
import type { Pattern } from '../types/pattern.js';
export declare class SemanticHasher {
    private vocabulary;
    private documentCount;
    /**
     * Compute semantic hash for exact duplicate detection
     */
    computeSemanticHash(pattern: Pattern): string;
    /**
     * Compute TF-IDF embedding for similarity calculation
     */
    computeEmbedding(pattern: Pattern): Map<string, number>;
    /**
     * Calculate cosine similarity between two embeddings
     */
    cosineSimilarity(emb1: Map<string, number>, emb2: Map<string, number>): number;
    /**
     * Update vocabulary with IDF values from a set of patterns
     */
    updateVocabulary(patterns: Pattern[]): void;
    /**
     * Extract key terms for semantic hashing
     */
    private extractKeyTerms;
    /**
     * Tokenize text into words
     */
    private tokenize;
}
/**
 * Singleton instance for global use
 */
export declare const semanticHasher: SemanticHasher;
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