cflipsign.js (1669B)
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 isNegativeZero = require( './../../../../base/assert/is-negative-zero' ); 24 25 26 // MAIN // 27 28 /** 29 * Returns a complex number with the same magnitude as `z` and the sign of `y*z`. 30 * 31 * @private 32 * @param {(Array|TypedArray|Object)} out - output array 33 * @param {number} re - real component 34 * @param {number} im - imaginary component 35 * @param {number} y - number from which to derive the sign 36 * @returns {(Array|TypedArray|Object)} function result 37 * 38 * @example 39 * var out = new Array( 2 ); 40 * 41 * var v = cflipsign( out, -4.2, 5.5, 55 ); 42 * // returns [ -4.2, 5.5 ] 43 * 44 * var bool = ( v === out ); 45 * // returns true 46 * 47 * @example 48 * var out = new Array( 2 ); 49 * var v = cflipsign( out, 0.0, 0.0, -8 ); 50 * // returns [ -0.0, -0.0 ] 51 * 52 * @example 53 * var out = new Array( 2 ); 54 * var v = cflipsign( out, NaN, NaN, 9 ); 55 * // returns [ NaN, NaN ] 56 */ 57 function cflipsign( out, re, im, y ) { 58 if ( y < 0 || isNegativeZero( y ) ) { 59 re = -re; 60 im = -im; 61 } 62 out[ 0 ] = re; 63 out[ 1 ] = im; 64 return out; 65 } 66 67 68 // EXPORTS // 69 70 module.exports = cflipsign;