srange.js (1802B)
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 float64ToFloat32 = require( '@stdlib/number/float64/base/to-float32' ); 24 var isnanf = require( '@stdlib/math/base/assert/is-nanf' ); 25 26 27 // MAIN // 28 29 /** 30 * Computes the range 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} range 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 = srange( N, x, 1 ); 44 * // returns 4.0 45 */ 46 function srange( N, x, stride ) { 47 var max; 48 var min; 49 var ix; 50 var v; 51 var i; 52 53 if ( N <= 0 ) { 54 return NaN; 55 } 56 if ( N === 1 || stride === 0 ) { 57 if ( isnanf( x[ 0 ] ) ) { 58 return NaN; 59 } 60 return 0.0; 61 } 62 if ( stride < 0 ) { 63 ix = (1-N) * stride; 64 } else { 65 ix = 0; 66 } 67 min = x[ ix ]; 68 max = min; 69 for ( i = 1; i < N; i++ ) { 70 ix += stride; 71 v = x[ ix ]; 72 if ( isnanf( v ) ) { 73 return v; 74 } 75 if ( v < min ) { 76 min = v; 77 } else if ( v > max ) { 78 max = v; 79 } 80 } 81 return float64ToFloat32( max - min ); 82 } 83 84 85 // EXPORTS // 86 87 module.exports = srange;