ndarray.js (1918B)
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 * @param {NonNegativeInteger} offset - starting index 36 * @returns {number} range 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, 1.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0 ] ); 43 * var N = floor( x.length / 2 ); 44 * 45 * var v = srange( N, x, 2, 1 ); 46 * // returns 6.0 47 */ 48 function srange( N, x, stride, offset ) { 49 var max; 50 var min; 51 var ix; 52 var v; 53 var i; 54 55 if ( N <= 0 ) { 56 return NaN; 57 } 58 if ( N === 1 || stride === 0 ) { 59 if ( isnanf( x[ offset ] ) ) { 60 return NaN; 61 } 62 return 0.0; 63 } 64 ix = offset; 65 min = x[ ix ]; 66 max = min; 67 for ( i = 1; i < N; i++ ) { 68 ix += stride; 69 v = x[ ix ]; 70 if ( isnanf( v ) ) { 71 return v; 72 } 73 if ( v < min ) { 74 min = v; 75 } else if ( v > max ) { 76 max = v; 77 } 78 } 79 return float64ToFloat32( max - min ); 80 } 81 82 83 // EXPORTS // 84 85 module.exports = srange;