hypot.js (1275B)
1 /** 2 * @license Apache-2.0 3 * 4 * Copyright (c) 2018 The Stdlib Authors. 5 * 6 * Licensed under the Apache License, Version 2.0 (the "License"); 7 * you may not use this file except in compliance with the License. 8 * You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, software 13 * distributed under the License is distributed on an "AS IS" BASIS, 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 * See the License for the specific language governing permissions and 16 * limitations under the License. 17 */ 18 19 'use strict'; 20 21 // MODULES // 22 23 var abs = require( './../../../../../base/special/fast/abs' ); 24 25 26 // VARIABLES // 27 28 // 2*cos(pi/8)/(1+cos(pi/8)): 29 var ALPHA = 0.96043387010342; 30 31 // 2*sin(pi/8)/(1+cos(pi/8)): 32 var BETA = 0.397824734759316; 33 34 35 // MAIN // 36 37 /** 38 * Computes the hypotenuse using the alpha max plus beta min algorithm. 39 * 40 * @param {number} x - number 41 * @param {number} y - number 42 * @returns {number} hypotenuse 43 * 44 * @example 45 * var h = hypot( -5.0, 12.0 ); 46 * // returns ~13.5 47 */ 48 function hypot( x, y ) { 49 x = abs( x ); 50 y = abs( y ); 51 if ( x > y ) { 52 return (ALPHA*x) + (BETA*y); 53 } 54 return (ALPHA*y) + (BETA*x); 55 } 56 57 58 // EXPORTS // 59 60 module.exports = hypot;