ndarray.js (1706B)
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 25 26 // MAIN // 27 28 /** 29 * Computes the range of a strided array. 30 * 31 * @param {PositiveInteger} N - number of indexed elements 32 * @param {NumericArray} x - input array 33 * @param {integer} stride - stride length 34 * @param {NonNegativeInteger} offset - starting index 35 * @returns {number} range 36 * 37 * @example 38 * var floor = require( '@stdlib/math/base/special/floor' ); 39 * 40 * var x = [ 2.0, 1.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0 ]; 41 * var N = floor( x.length / 2 ); 42 * 43 * var v = range( N, x, 2, 1 ); 44 * // returns 6.0 45 */ 46 function range( N, x, stride, offset ) { 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 ( isnan( x[ offset ] ) ) { 58 return NaN; 59 } 60 return 0.0; 61 } 62 ix = offset; 63 min = x[ ix ]; 64 max = min; 65 for ( i = 1; i < N; i++ ) { 66 ix += stride; 67 v = x[ ix ]; 68 if ( isnan( v ) ) { 69 return v; 70 } 71 if ( v < min ) { 72 min = v; 73 } else if ( v > max ) { 74 max = v; 75 } 76 } 77 return max - min; 78 } 79 80 81 // EXPORTS // 82 83 module.exports = range;