README.md (1725B)
1 <!-- 2 3 @license Apache-2.0 4 5 Copyright (c) 2018 The Stdlib Authors. 6 7 Licensed under the Apache License, Version 2.0 (the "License"); 8 you may not use this file except in compliance with the License. 9 You may obtain a copy of the License at 10 11 http://www.apache.org/licenses/LICENSE-2.0 12 13 Unless required by applicable law or agreed to in writing, software 14 distributed under the License is distributed on an "AS IS" BASIS, 15 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 16 See the License for the specific language governing permissions and 17 limitations under the License. 18 19 --> 20 21 # Natural Logarithm 22 23 > Evaluate the [natural logarithm][natural-logarithm]. 24 25 <section class="usage"> 26 27 ## Usage 28 29 ```javascript 30 var ln = require( '@stdlib/math/base/special/ln' ); 31 ``` 32 33 #### ln( x ) 34 35 Evaluates the [natural logarithm][natural-logarithm]. 36 37 ```javascript 38 var v = ln( 4.0 ); 39 // returns ~1.386 40 41 v = ln( 0.0 ); 42 // returns -Infinity 43 44 v = ln( Infinity ); 45 // returns Infinity 46 47 v = ln( NaN ); 48 // returns NaN 49 ``` 50 51 For negative numbers, the [natural logarithm][natural-logarithm] is **not** defined. 52 53 ```javascript 54 var v = ln( -4.0 ); 55 // returns NaN 56 ``` 57 58 </section> 59 60 <!-- /.usage --> 61 62 <section class="examples"> 63 64 ## Examples 65 66 <!-- eslint no-undef: "error" --> 67 68 ```javascript 69 var randu = require( '@stdlib/random/base/randu' ); 70 var round = require( '@stdlib/math/base/special/round' ); 71 var ln = require( '@stdlib/math/base/special/ln' ); 72 73 var x; 74 var i; 75 76 for ( i = 0; i < 100; i++ ) { 77 x = round( randu() * 100.0 ); 78 console.log( 'ln(%d) = %d', x, ln( x ) ); 79 } 80 ``` 81 82 </section> 83 84 <!-- /.examples --> 85 86 <section class="links"> 87 88 [natural-logarithm]: https://en.wikipedia.org/wiki/Natural_logarithm 89 90 </section> 91 92 <!-- /.links -->