ndarray.js (2376B)
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 double-precision floating-point strided array according to a mask, ignoring `NaN` values. 30 * 31 * @param {PositiveInteger} N - number of indexed elements 32 * @param {Float64Array} x - input array 33 * @param {integer} strideX - `x` stride length 34 * @param {NonNegativeInteger} offsetX - `x` starting index 35 * @param {Uint8Array} mask - mask array 36 * @param {integer} strideMask - `mask` stride length 37 * @param {NonNegativeInteger} offsetMask - `mask` starting index 38 * @returns {number} range 39 * 40 * @example 41 * var Float64Array = require( '@stdlib/array/float64' ); 42 * var Uint8Array = require( '@stdlib/array/uint8' ); 43 * var floor = require( '@stdlib/math/base/special/floor' ); 44 * 45 * var x = new Float64Array( [ 2.0, 1.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] ); 46 * var mask = new Uint8Array( [ 0, 0, 0, 0, 0, 0, 0, 0, 1, 1 ] ); 47 * var N = floor( x.length / 2 ); 48 * 49 * var v = dnanmskrange( N, x, 2, 1, mask, 2, 1 ); 50 * // returns 6.0 51 */ 52 function dnanmskrange( N, x, strideX, offsetX, mask, strideMask, offsetMask ) { 53 var max; 54 var min; 55 var ix; 56 var im; 57 var v; 58 var i; 59 60 if ( N <= 0 ) { 61 return NaN; 62 } 63 ix = offsetX; 64 im = offsetMask; 65 for ( i = 0; i < N; i++ ) { 66 v = x[ ix ]; 67 if ( v === v && mask[ im ] === 0 ) { 68 break; 69 } 70 ix += strideX; 71 im += strideMask; 72 } 73 if ( i === N ) { 74 return NaN; 75 } 76 min = v; 77 max = min; 78 i += 1; 79 for ( i; i < N; i++ ) { 80 ix += strideX; 81 im += strideMask; 82 if ( mask[ im ] ) { 83 continue; 84 } 85 v = x[ ix ]; 86 if ( isnan( v ) ) { 87 continue; 88 } 89 if ( v < min ) { 90 min = v; 91 } else if ( v > max ) { 92 max = v; 93 } 94 } 95 return max - min; 96 } 97 98 99 // EXPORTS // 100 101 module.exports = dnanmskrange;