README.md (3256B)
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 # ceiln 22 23 > Round a complex number to the nearest multiple of `10^n` toward positive infinity. 24 25 <section class="usage"> 26 27 ## Usage 28 29 ```javascript 30 var cceiln = require( '@stdlib/math/base/special/cceiln' ); 31 ``` 32 33 #### cceiln( \[out,] re, im, n ) 34 35 Rounds a `complex` number comprised of a **real** component `re` and an **imaginary** component `im` to the nearest multiple of `10^n` toward positive infinity. 36 37 ```javascript 38 // Round components to 2 decimal places: 39 var v = cceiln( -3.141592653589793, 3.141592653589793, -2 ); 40 // returns [ -3.14, 3.15 ] 41 42 // If n = 0, `cceiln` behaves like `cceil`: 43 v = cceiln( -3.141592653589793, 3.141592653589793, 0 ); 44 // returns [ -3.0, 4.0 ] 45 46 // Round components to the nearest thousand: 47 v = cceiln( -12368.0, 12368.0, 3 ); 48 // returns [ -12000.0, 13000.0 ] 49 50 v = cceiln( NaN, NaN, 0 ); 51 // returns [ NaN, NaN ] 52 ``` 53 54 By default, the function returns real and imaginary components as a two-element `array`. To avoid unnecessary memory allocation, the function supports providing an output (destination) object. 55 56 ```javascript 57 var Float32Array = require( '@stdlib/array/float32' ); 58 59 var out = new Float32Array( 2 ); 60 61 var v = cceiln( out, -4.2, 5.5, 0 ); 62 // returns <Float32Array>[ -4.0, 6.0 ] 63 64 var bool = ( v === out ); 65 // returns true 66 ``` 67 68 </section> 69 70 <!-- /.usage --> 71 72 <section class="notes"> 73 74 ## Notes 75 76 - When operating on [floating-point numbers][ieee754] in bases other than `2`, rounding to specified digits can be **inexact**. For example, 77 78 ```javascript 79 var x = 0.2 + 0.1; 80 // returns 0.30000000000000004 81 82 // Should round components to 0.3: 83 var v = cceiln( x, x, -16 ); 84 // returns [ 0.3000000000000001, 0.3000000000000001 ] 85 ``` 86 87 </section> 88 89 <!-- /.notes --> 90 91 <section class="examples"> 92 93 ## Examples 94 95 <!-- eslint no-undef: "error" --> 96 97 ```javascript 98 var Complex128 = require( '@stdlib/complex/float64' ); 99 var randu = require( '@stdlib/random/base/randu' ); 100 var ceil = require( '@stdlib/math/base/special/ceil' ); 101 var real = require( '@stdlib/complex/real' ); 102 var imag = require( '@stdlib/complex/imag' ); 103 var cceiln = require( '@stdlib/math/base/special/cceiln' ); 104 105 var re; 106 var im; 107 var z; 108 var o; 109 var w; 110 var n; 111 var i; 112 113 for ( i = 0; i < 100; i++ ) { 114 re = ( randu()*100.0 ) - 50.0; 115 im = ( randu()*100.0 ) - 50.0; 116 z = new Complex128( re, im ); 117 118 n = ceil( randu()*5.0 ); 119 o = cceiln( real(z), imag(z), -n ); 120 w = new Complex128( o[ 0 ], o[ 1 ] ); 121 122 console.log( 'ceiln(%s,%s) = %s', z.toString(), n.toString(), w.toString() ); 123 } 124 ``` 125 126 </section> 127 128 <!-- /.examples --> 129 130 <section class="links"> 131 132 [ieee754]: https://en.wikipedia.org/wiki/IEEE_754-1985 133 134 </section> 135 136 <!-- /.links -->