/**
 * Method of interpolation.
 */
export declare type InterpolationMethod = 'linear' | 'nearest' | 'next' | 'previous';
/**
 * Interpolates values linearly in one dimension.
 *
 * @param  xs     Array of independent sample points.
 * @param  vs     Array of dependent values v(x) with length equal to xs.
 * @param  xqs    Array of query points.
 * @param  method Method of interpolation.
 * @return        Interpolated values vq(xq) with length equal to xqs.
 */
export default function interp1(xs: ReadonlyArray<number>, vs: ReadonlyArray<number>, xqs: ReadonlyArray<number>, method?: InterpolationMethod): number[];