export interface KneedleOptions {
    /**
     * `'concave'`: curves that decrease and flatten; `'convex'`: curves that increase and flatten.
     */
    direction?: 'concave' | 'convex';
    /** Higher values require a more pronounced knee. */
    sensitivity?: number;
}
export interface KneedleResult {
    knee_x: number | null;
    knee_index: number | null;
    differences: number[];
}
/** Simplified Kneedle algorithm (Satopaa et al., 2011). */
export declare function find_knee(x_values: number[], y_values: number[], options?: KneedleOptions): KneedleResult;