import { AngularDiameterMethod } from '../enums/AngularDiameterMethod.js';
import { AngularDistanceMethod } from '../enums/AngularDistanceMethod.js';
import { EcfVec3, Kilometers, Radians, SpaceObjectType } from '../types/types.js';
/**
 * Calculates the factorial of a given number.
 * @param n - The number to calculate the factorial for.
 * @returns The factorial of the given number.
 */
export declare function factorial(n: number): number;
/**
 * Calculates the base 10 logarithm of a number.
 * @param x - The number to calculate the logarithm for.
 * @returns The base 10 logarithm of the input number.
 */
export declare function log10(x: number): number;
/**
 * Calculates the hyperbolic secant of a number.
 * @param x - The number to calculate the hyperbolic secant of.
 * @returns The hyperbolic secant of the given number.
 */
export declare function sech(x: number): number;
/**
 * Calculates the hyperbolic cosecant of a number.
 * @param x - The number for which to calculate the hyperbolic cosecant.
 * @returns The hyperbolic cosecant of the given number.
 */
export declare function csch(x: number): number;
/**
 * Returns the inverse hyperbolic cosecant of a number.
 * @param x - The number to calculate the inverse hyperbolic cosecant of.
 * @returns The inverse hyperbolic cosecant of the given number.
 */
export declare function acsch(x: number): number;
/**
 * Calculates the inverse hyperbolic secant (asech) of a number.
 * @param x - The number to calculate the inverse hyperbolic secant of.
 * @returns The inverse hyperbolic secant of the given number.
 */
export declare function asech(x: number): number;
/**
 * Calculates the inverse hyperbolic cotangent (acoth) of a number.
 * @param x - The number to calculate the acoth of.
 * @returns The inverse hyperbolic cotangent of the given number.
 */
export declare function acoth(x: number): number;
/**
 * Copies the sign of the second number to the first number.
 * @param mag - The magnitude of the number.
 * @param sgn - The sign of the number.
 * @returns The number with the magnitude of `mag` and the sign of `sgn`.
 */
export declare function copySign(mag: number, sgn: number): number;
/**
 * Evaluates a polynomial function at a given value.
 * @param x - The value at which to evaluate the polynomial.
 * @param coeffs - The coefficients of the polynomial.
 * @returns The result of evaluating the polynomial at the given value.
 */
export declare function evalPoly(x: number, coeffs: Float64Array): number;
/**
 * Concatenates two Float64Arrays into a new Float64Array.
 * @param a - The first Float64Array.
 * @param b - The second Float64Array.
 * @returns A new Float64Array containing the concatenated values of `a` and `b`.
 */
export declare function concat(a: Float64Array, b: Float64Array): Float64Array;
/**
 * Calculates the angle in the half-plane that best matches the given angle.
 * @param angle - The angle to be matched.
 * @param match - The angle to be matched against.
 * @returns The angle in the half-plane that best matches the given angle.
 */
export declare function matchHalfPlane(angle: number, match: number): number;
/**
 * Wraps an angle to the range [-π, π].
 * @param theta - The angle to wrap.
 * @returns The wrapped angle.
 */
export declare function wrapAngle(theta: Radians): Radians;
/**
 * Calculates the angular distance between two points on a sphere.
 * @param lam1 The longitude of the first point.
 * @param phi1 The latitude of the first point.
 * @param lam2 The longitude of the second point.
 * @param phi2 The latitude of the second point.
 * @param method The method to use for calculating the angular distance. Defaults to AngularDistanceMethod.Cosine.
 * @returns The angular distance between the two points.
 * @throws Error if an invalid angular distance method is provided.
 */
export declare function angularDistance(lam1: number, phi1: number, lam2: number, phi2: number, method?: AngularDistanceMethod): Radians;
/**
 * Calculates the angular diameter of an object.
 * @param diameter - The diameter of the object.
 * @param distance - The distance to the object.
 * @param method - The method used to calculate the angular diameter. Defaults to AngularDiameterMethod.Sphere.
 * @returns The angular diameter of the object.
 * @throws Error if an invalid angular diameter method is provided.
 */
export declare function angularDiameter(diameter: number, distance: number, method?: AngularDiameterMethod): number;
/**
 * Performs linear interpolation between two points.
 * @param x - The x-coordinate to interpolate.
 * @param x0 - The x-coordinate of the first point.
 * @param y0 - The y-coordinate of the first point.
 * @param x1 - The x-coordinate of the second point.
 * @param y1 - The y-coordinate of the second point.
 * @returns The interpolated y-coordinate corresponding to the given x-coordinate.
 */
export declare function linearInterpolate(x: number, x0: number, y0: number, x1: number, y1: number): number;
/**
 * Calculates the mean value of an array of numbers.
 * @param values - The array of numbers.
 * @returns The mean value of the numbers.
 */
export declare function mean(values: number[]): number;
/**
 * Calculates the standard deviation of an array of numbers.
 * @param values - The array of numbers.
 * @param isSample - Optional. Specifies whether the array represents a sample. Default is false.
 * @returns The standard deviation of the array.
 */
export declare function std(values: number[], isSample?: boolean): number;
/**
 * Calculates the covariance between two arrays.
 * @param a - The first array.
 * @param b - The second array.
 * @param isSample - Optional. Specifies whether the arrays represent a sample. Default is false.
 * @returns The covariance between the two arrays.
 */
export declare function covariance(a: number[], b: number[], isSample?: boolean): number;
/**
 * Calculates the gamma function of a number.
 * @param n - The input number.
 * @returns The gamma function value.
 */
export declare function gamma(n: number): number;
/**
 * Calculates the eccentric anomaly (e0) and true anomaly (nu) using Newton's method
 * for a given eccentricity (ecc) and mean anomaly (m).
 * @param ecc - The eccentricity of the orbit.
 * @param m - The mean anomaly.
 * @returns An object containing the eccentric anomaly (e0) and true anomaly (nu).
 */
export declare function newtonM(ecc: number, m: number): {
    e0: number;
    nu: number;
};
/**
 * Calculates the eccentric anomaly (e0) and mean anomaly (m) using Newton's method
 * for a given eccentricity (ecc) and true anomaly (nu).
 * @param ecc - The eccentricity of the orbit.
 * @param nu - The true anomaly.
 * @returns An object containing the calculated eccentric anomaly (e0) and mean anomaly (m).
 */
export declare function newtonNu(ecc: number, nu: number): {
    e0: number;
    m: Radians;
};
/**
 * Creates a 2D array with the specified number of rows and columns, filled with the same given value.
 * @template T The type of elements in the array.
 * @param rows The number of rows in the 2D array.
 * @param columns The number of columns in the 2D array.
 * @param value The value to fill the array with.
 * @returns The 2D array with the specified number of rows and columns, filled with the given value.
 */
export declare function array2d<T>(rows: number, columns: number, value: T): T[][];
/**
 * Clamps a number between a minimum and maximum value.
 * @param x The number to clamp.
 * @param min The minimum value.
 * @param max The maximum value.
 * @returns The clamped number.
 */
export declare function clamp(x: number, min: number, max: number): number;
/**
 * Determines whether a given year is a leap year.
 * @param dateIn The date to check.
 * @returns `true` if the year is a leap year, `false` otherwise.
 */
export declare function isLeapYear(dateIn: Date): boolean;
/**
 * Calculates the day of the year for a given date.
 * If no date is provided, the current date is used.
 *
 * This is sometimes referred to as the Jday, but is
 * very different from the Julian day used in astronomy.
 * @param date - The date for which to calculate the day of the year.
 * @returns The day of the year as a number.
 */
export declare function getDayOfYear(date?: Date): number;
/**
 * Rounds a number to a specified number of decimal places.
 * @param value - The number to round.
 * @param places - The number of decimal places to round to.
 * @returns The rounded number.
 */
export declare function toPrecision(value: number, places: number): number;
/**
 * Returns the sign of a number.
 * @param value - The number to determine the sign of.
 * @returns 1 if the number is positive, -1 if the number is negative.
 */
export declare function sign(value: number): 1 | -1;
/**
 * Converts a SpaceObjectType to a string representation.
 * @param spaceObjType - The SpaceObjectType to convert.
 * @returns The string representation of the SpaceObjectType.
 */
export declare const spaceObjType2Str: (spaceObjType: SpaceObjectType) => string;
/**
 * Calculates the Doppler factor for a given location, position, and velocity.
 * The Doppler factor is a measure of the change in frequency or wavelength of a wave
 * as observed by an observer moving relative to the source of the wave.
 * @param location - The location vector of the observer.
 * @param position - The position vector of the source.
 * @param velocity - The velocity vector of the source.
 * @returns The calculated Doppler factor.
 */
export declare const dopplerFactor: (location: EcfVec3<Kilometers>, position: EcfVec3<Kilometers>, velocity: EcfVec3<Kilometers>) => number;
/**
 * Creates an array of numbers from start to stop (inclusive) with the specified step.
 * @param start The starting number.
 * @param stop The ending number.
 * @param step The step value.
 * @returns An array of numbers.
 */
export declare function createVec(start: number, stop: number, step: number): number[];