ndarray.js (1824B)
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 isnanf = require( '@stdlib/math/base/assert/is-nanf' ); 24 var abs = require( '@stdlib/math/base/special/abs' ); 25 26 27 // MAIN // 28 29 /** 30 * Computes the maximum absolute value of a sorted single-precision floating-point strided array. 31 * 32 * @param {PositiveInteger} N - number of indexed elements 33 * @param {Float32Array} x - sorted input array 34 * @param {integer} stride - stride length 35 * @param {NonNegativeInteger} offset - starting index 36 * @returns {number} maximum absolute value 37 * 38 * @example 39 * var Float32Array = require( '@stdlib/array/float32' ); 40 * var floor = require( '@stdlib/math/base/special/floor' ); 41 * 42 * var x = new Float32Array( [ 2.0, -3.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0 ] ); 43 * var N = floor( x.length / 2 ); 44 * 45 * var v = smaxabssorted( N, x, 2, 1 ); 46 * // returns 4.0 47 */ 48 function smaxabssorted( N, x, stride, offset ) { 49 var v1; 50 var v2; 51 52 if ( N <= 0 ) { 53 return NaN; 54 } 55 if ( N === 1 || stride === 0 ) { 56 return x[ 0 ]; 57 } 58 v1 = x[ offset ]; 59 v2 = x[ offset + ((N-1)*stride) ]; 60 if ( isnanf( v1 ) || isnanf( v2 ) ) { 61 return NaN; 62 } 63 v1 = abs( v1 ); 64 v2 = abs( v2 ); 65 if ( v1 > v2 ) { 66 return v1; 67 } 68 return v2; 69 } 70 71 72 // EXPORTS // 73 74 module.exports = smaxabssorted;