cexp.js (2113B)
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 copysign = require( './../../../../base/special/copysign' ); 24 var sincos = require( './../../../../base/special/sincos' ); 25 var isnan = require( './../../../../base/assert/is-nan' ); 26 var isInfinite = require( './../../../../base/assert/is-infinite' ); 27 var exp = require( './../../../../base/special/exp' ); 28 var PINF = require( '@stdlib/constants/float64/pinf' ); 29 var NINF = require( '@stdlib/constants/float64/ninf' ); 30 31 32 // MAIN // 33 34 /** 35 * Computes the exponential function of a complex number. 36 * 37 * @private 38 * @param {(Array|TypedArray|Object)} out - output array 39 * @param {number} re - real component 40 * @param {number} im - imaginary component 41 * @returns {(Array|TypedArray|Object)} output array 42 * 43 * @example 44 * var out = [ 0.0, 0.0 ]; 45 * 46 * var v = cexp( out, 0.0, 1.0 ); 47 * // returns [ ~0.540, ~0.841 ] 48 * 49 * var bool = ( v === out ); 50 * // returns true 51 */ 52 function cexp( out, re, im ) { 53 var tmp; 54 var e; 55 if ( isnan( re ) ) { 56 out[ 0 ] = NaN; 57 out[ 1 ] = ( im === 0.0 ) ? im : re; 58 } else if ( isInfinite( im ) ) { 59 if ( re === PINF ) { 60 out[ 0 ] = -re; 61 out[ 1 ] = NaN; 62 } else if ( re === NINF ) { 63 out[ 0 ] = -0.0; 64 out[ 1 ] = copysign( 0.0, im ); 65 } else { 66 out[ 0 ] = NaN; 67 out[ 1 ] = NaN; 68 } 69 } else { 70 e = exp( re ); 71 if ( im === 0.0 ) { 72 out[ 0 ] = e; 73 out[ 1 ] = im; 74 } else { 75 sincos( out, im ); 76 tmp = out[ 0 ]; 77 out[ 0 ] = out[ 1 ] * e; 78 out[ 1 ] = tmp * e; 79 } 80 } 81 return out; 82 } 83 84 85 // EXPORTS // 86 87 module.exports = cexp;