README.md (2168B)
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 # Rising Factorial 22 23 > Compute the [rising factorial][falling-and-rising-factorials]. 24 25 <section class="intro"> 26 27 </section> 28 29 <!-- /.intro --> 30 31 <section class="usage"> 32 33 ## Usage 34 35 ```javascript 36 var risingFactorial = require( '@stdlib/math/base/special/rising-factorial' ); 37 ``` 38 39 #### risingFactorial( x, n ) 40 41 Evaluates the [rising factorial][falling-and-rising-factorials] of `x` and `n`. 42 43 ```javascript 44 var v = risingFactorial( 0.9, 5 ); 45 // returns ~94.766 46 47 v = risingFactorial( -9.0, 3 ); 48 // returns -504.0 49 50 v = risingFactorial( 0.0, 2 ); 51 // returns 0.0 52 53 v = risingFactorial( 3.0, -2 ); 54 // returns 0.5 55 56 v = risingFactorial( NaN, 3 ); 57 // returns NaN 58 59 v = risingFactorial( 5.0, NaN ); 60 // returns NaN 61 62 v = risingFactorial( NaN, NaN ); 63 // returns NaN 64 ``` 65 66 The function returns `NaN` for non-integer `n`. 67 68 ```javascript 69 var v = risingFactorial( 2.0, 1.5 ); 70 // returns NaN 71 ``` 72 73 </section> 74 75 <!-- /.usage --> 76 77 <section class="examples"> 78 79 ## Examples 80 81 <!-- eslint no-undef: "error" --> 82 83 ```javascript 84 var randu = require( '@stdlib/random/base/randu' ); 85 var ceil = require( '@stdlib/math/base/special/ceil' ); 86 var risingFactorial = require( '@stdlib/math/base/special/rising-factorial' ); 87 88 var n; 89 var x; 90 var i; 91 92 for ( i = 0; i < 100; i++ ) { 93 x = ( randu()*40.0 ) - 20.0; 94 n = ceil( ( randu()*40.0 ) - 20.0 ); 95 console.log( 'risingFactorial(%d,%d) = %d', x, n, risingFactorial( x, n ) ); 96 } 97 ``` 98 99 </section> 100 101 <!-- /.examples --> 102 103 <section class="links"> 104 105 [falling-and-rising-factorials]: https://en.wikipedia.org/wiki/Falling_and_rising_factorials 106 107 </section> 108 109 <!-- /.links -->