nanminabs.js (1758B)
1 /** 2 * @license Apache-2.0 3 * 4 * Copyright (c) 2020 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 isnan = require( '@stdlib/math/base/assert/is-nan' ); 24 var abs = require( '@stdlib/math/base/special/abs' ); 25 26 27 // MAIN // 28 29 /** 30 * Computes the minimum absolute value of a strided array, ignoring `NaN` values. 31 * 32 * @param {PositiveInteger} N - number of indexed elements 33 * @param {NumericArray} x - input array 34 * @param {integer} stride - stride length 35 * @returns {number} minimum absolute value 36 * 37 * @example 38 * var x = [ 1.0, -2.0, NaN, 2.0 ]; 39 * var N = x.length; 40 * 41 * var v = nanminabs( N, x, 1 ); 42 * // returns 1.0 43 */ 44 function nanminabs( N, x, stride ) { 45 var min; 46 var ix; 47 var v; 48 var i; 49 50 if ( N <= 0 ) { 51 return NaN; 52 } 53 if ( N === 1 || stride === 0 ) { 54 return abs( x[ 0 ] ); 55 } 56 if ( stride < 0 ) { 57 ix = (1-N) * stride; 58 } else { 59 ix = 0; 60 } 61 for ( i = 0; i < N; i++ ) { 62 v = x[ ix ]; 63 if ( v === v ) { 64 break; 65 } 66 ix += stride; 67 } 68 if ( i === N ) { 69 return NaN; 70 } 71 min = abs( v ); 72 i += 1; 73 for ( i; i < N; i++ ) { 74 ix += stride; 75 v = abs( x[ ix ] ); 76 if ( isnan( v ) ) { 77 continue; 78 } 79 if ( v < min ) { 80 min = v; 81 } 82 } 83 return min; 84 } 85 86 87 // EXPORTS // 88 89 module.exports = nanminabs;