/**
 * Parallel execution of multiple research tracks
 * Enables concurrent research paths for more efficient deep research
 */
import { createStep } from '../utils/steps.js';
import { ResearchState, ResearchStep } from '../types/pipeline.js';
import { TrackResult } from './track.js';
import { ProcessingError } from '../types/errors.js';
/**
 * Custom error for parallel execution issues
 */
export declare class ParallelError extends ProcessingError {
    constructor(options: Omit<ConstructorParameters<typeof ProcessingError>[0], 'code'>);
}
/**
 * Options for parallel execution
 */
export interface ParallelOptions {
    /** An array of steps to execute in parallel */
    tracks: ResearchStep[];
    /** Whether to continue execution if one track fails */
    continueOnError?: boolean;
    /** Maximum time in ms to wait for all tracks to complete */
    timeout?: number;
    /** Function to merge results from all tracks */
    mergeFunction?: (tracks: Record<string, TrackResult>, state: ResearchState) => any;
    /** Whether to include the merged result in the results array */
    includeInResults?: boolean;
    /** Retry configuration for the parallel step */
    retry?: {
        /** Maximum number of retries */
        maxRetries?: number;
        /** Base delay between retries in ms */
        baseDelay?: number;
    };
}
/**
 * Creates a parallel execution step
 *
 * @param options Options for parallel execution
 * @returns A research step that executes tracks in parallel
 */
export declare function parallel(options: ParallelOptions): ReturnType<typeof createStep>;
/**
 * Default merge function that combines results from all tracks
 *
 * @param tracks The track results to merge
 * @returns A merged result object
 */
export declare function defaultMergeFunction(tracks: Record<string, TrackResult>): Record<string, any>;