import type { NumberArray } from 'cheminfo-types';
/**
 * Updates the system matrix with new weights and computes the weighted right-hand side vector.
 * @param matrix - The lower triangular non-zeros matrix in triplet format.
 * @param y - The original data vector.
 * @param weights - The weights vector.
 * @returns A tuple of the updated matrix and the weighted right-hand side vector.
 */
export declare function updateSystem(matrix: number[][], y: NumberArray, weights: NumberArray): [number[][], Float64Array];
/**
 * Constructs the delta matrix and applies Cuthill-McKee permutation.
 * @param nbPoints - Number of data points.
 * @param lambda - Smoothing parameter.
 * @returns An object containing the lower triangular non-zeros matrix and the permutation array.
 */
export declare function getDeltaMatrix(nbPoints: number, lambda: number): {
    lowerTriangularNonZeros: number[][];
    permutationEncodedArray: Float64Array;
};
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