smax.js (1726B)
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 isPositiveZerof = require( '@stdlib/math/base/assert/is-positive-zerof' ); 25 26 27 // MAIN // 28 29 /** 30 * Computes the maximum value of a single-precision floating-point strided array. 31 * 32 * @param {PositiveInteger} N - number of indexed elements 33 * @param {Float32Array} x - input array 34 * @param {integer} stride - stride length 35 * @returns {number} maximum value 36 * 37 * @example 38 * var Float32Array = require( '@stdlib/array/float32' ); 39 * 40 * var x = new Float32Array( [ 1.0, -2.0, 2.0 ] ); 41 * var N = x.length; 42 * 43 * var v = smax( N, x, 1 ); 44 * // returns 2.0 45 */ 46 function smax( N, x, stride ) { 47 var max; 48 var ix; 49 var v; 50 var i; 51 52 if ( N <= 0 ) { 53 return NaN; 54 } 55 if ( N === 1 || stride === 0 ) { 56 return x[ 0 ]; 57 } 58 if ( stride < 0 ) { 59 ix = (1-N) * stride; 60 } else { 61 ix = 0; 62 } 63 max = x[ ix ]; 64 for ( i = 1; i < N; i++ ) { 65 ix += stride; 66 v = x[ ix ]; 67 if ( isnanf( v ) ) { 68 return v; 69 } 70 if ( v > max || ( v === max && isPositiveZerof( v ) ) ) { 71 max = v; 72 } 73 } 74 return max; 75 } 76 77 78 // EXPORTS // 79 80 module.exports = smax;