README.md (3510B)
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 # incrmminmaxabs 22 23 > Compute moving minimum and maximum absolute values incrementally. 24 25 <section class="usage"> 26 27 ## Usage 28 29 ```javascript 30 var incrmminmaxabs = require( '@stdlib/stats/incr/mminmaxabs' ); 31 ``` 32 33 #### incrmminmaxabs( \[out,] window ) 34 35 Returns an accumulator `function` which incrementally computes moving minimum and maximum absolute values. The `window` parameter defines the number of values over which to compute moving minimum and maximum absolute values. 36 37 ```javascript 38 var accumulator = incrmminmaxabs( 3 ); 39 ``` 40 41 By default, the returned accumulator `function` returns the minimum and maximum as a two-element `array`. To avoid unnecessary memory allocation, the function supports providing an output (destination) object. 42 43 ```javascript 44 var Float64Array = require( '@stdlib/array/float64' ); 45 46 var accumulator = incrmminmaxabs( new Float64Array( 2 ), 3 ); 47 ``` 48 49 #### accumulator( \[x] ) 50 51 If provided an input value `x`, the accumulator function returns updated minimum and maximum absolute values. If not provided an input value `x`, the accumulator function returns the current minimum and maximum absolute values. 52 53 ```javascript 54 var accumulator = incrmminmaxabs( 3 ); 55 56 var mm = accumulator(); 57 // returns null 58 59 // Fill the window... 60 mm = accumulator( 2.0 ); // [2.0] 61 // returns [ 2.0, 2.0 ] 62 63 mm = accumulator( 1.0 ); // [2.0, 1.0] 64 // returns [ 1.0, 2.0 ] 65 66 mm = accumulator( 3.0 ); // [2.0, 1.0, 3.0] 67 // returns [ 1.0, 3.0 ] 68 69 // Window begins sliding... 70 mm = accumulator( -7.0 ); // [1.0, 3.0, -7.0] 71 // returns [ 1.0, 7.0 ] 72 73 mm = accumulator( -5.0 ); // [3.0, -7.0, -5.0] 74 // returns [ 3.0, 7.0 ] 75 76 mm = accumulator(); 77 // returns [ 3.0, 7.0 ] 78 ``` 79 80 </section> 81 82 <!-- /.usage --> 83 84 <section class="notes"> 85 86 ## Notes 87 88 - Input values are **not** type checked. If provided `NaN`, the accumulated minimum and maximum values are `NaN` for **at least** `W-1` future invocations. If non-numeric inputs are possible, you are advised to type check and handle accordingly **before** passing the value to the accumulator function. 89 - As `W` values are needed to fill the window buffer, the first `W-1` returned minimum and maximum values are calculated from smaller sample sizes. Until the window is full, each returned minimum and maximum is calculated from all provided values. 90 91 </section> 92 93 <!-- /.notes --> 94 95 <section class="examples"> 96 97 ## Examples 98 99 <!-- eslint no-undef: "error" --> 100 101 ```javascript 102 var randu = require( '@stdlib/random/base/randu' ); 103 var incrmminmaxabs = require( '@stdlib/stats/incr/mminmaxabs' ); 104 105 var accumulator; 106 var v; 107 var i; 108 109 // Initialize an accumulator: 110 accumulator = incrmminmaxabs( 5 ); 111 112 // For each simulated datum, update the moving minimum and maximum absolute values... 113 for ( i = 0; i < 100; i++ ) { 114 v = ( randu()*100.0 ) - 50.0; 115 accumulator( v ); 116 } 117 console.log( accumulator() ); 118 ``` 119 120 </section> 121 122 <!-- /.examples --> 123 124 <section class="links"> 125 126 </section> 127 128 <!-- /.links -->