import { BaseRetriever, BaseRetrieverInput } from "@langchain/core/retrievers";
import { Document, DocumentInterface } from "@langchain/core/documents";
import { CallbackManagerForRetrieverRun } from "@langchain/core/callbacks/manager";
export interface EnsembleRetrieverInput extends BaseRetrieverInput {
    /** A list of retrievers to ensemble. */
    retrievers: BaseRetriever[];
    /**
     * A list of weights corresponding to the retrievers. Defaults to equal
     * weighting for all retrievers.
     */
    weights?: number[];
    /**
     * A constant added to the rank, controlling the balance between the importance
     * of high-ranked items and the consideration given to lower-ranked items.
     * Default is 60.
     */
    c?: number;
}
/**
 * Ensemble retriever that aggregates and orders the results of
 * multiple retrievers by using weighted Reciprocal Rank Fusion.
 */
export declare class EnsembleRetriever extends BaseRetriever {
    static lc_name(): string;
    lc_namespace: string[];
    retrievers: BaseRetriever[];
    weights: number[];
    c: number;
    constructor(args: EnsembleRetrieverInput);
    _getRelevantDocuments(query: string, runManager?: CallbackManagerForRetrieverRun): Promise<Document<Record<string, any>>[]>;
    _rankFusion(query: string, runManager?: CallbackManagerForRetrieverRun): Promise<Document<Record<string, any>>[]>;
    _weightedReciprocalRank(docList: DocumentInterface[][]): Promise<Document<Record<string, any>>[]>;
    private _uniqueUnion;
}