snanmskrange.js (2308B)
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 according to a mask, ignoring `NaN` values. 31 * 32 * @param {PositiveInteger} N - number of indexed elements 33 * @param {Float32Array} x - input array 34 * @param {integer} strideX - `x` stride length 35 * @param {Uint8Array} mask - mask array 36 * @param {integer} strideMask - `mask` stride length 37 * @returns {number} range 38 * 39 * @example 40 * var Float32Array = require( '@stdlib/array/float32' ); 41 * var Uint8Array = require( '@stdlib/array/uint8' ); 42 * 43 * var x = new Float32Array( [ 1.0, -2.0, 4.0, 2.0, NaN ] ); 44 * var mask = new Uint8Array( [ 0, 0, 1, 0, 0 ] ); 45 * 46 * var v = snanmskrange( x.length, x, 1, mask, 1 ); 47 * // returns 4.0 48 */ 49 function snanmskrange( N, x, strideX, mask, strideMask ) { 50 var max; 51 var min; 52 var ix; 53 var im; 54 var v; 55 var i; 56 57 if ( N <= 0 ) { 58 return NaN; 59 } 60 if ( strideX < 0 ) { 61 ix = (1-N) * strideX; 62 } else { 63 ix = 0; 64 } 65 if ( strideMask < 0 ) { 66 im = (1-N) * strideMask; 67 } else { 68 im = 0; 69 } 70 for ( i = 0; i < N; i++ ) { 71 v = x[ ix ]; 72 if ( v === v && mask[ im ] === 0 ) { 73 break; 74 } 75 ix += strideX; 76 im += strideMask; 77 } 78 if ( i === N ) { 79 return NaN; 80 } 81 min = v; 82 max = min; 83 i += 1; 84 for ( i; i < N; i++ ) { 85 ix += strideX; 86 im += strideMask; 87 if ( mask[ im ] ) { 88 continue; 89 } 90 v = x[ ix ]; 91 if ( isnanf( v ) ) { 92 continue; 93 } 94 if ( v < min ) { 95 min = v; 96 } else if ( v > max ) { 97 max = v; 98 } 99 } 100 return float64ToFloat32( max - min ); 101 } 102 103 104 // EXPORTS // 105 106 module.exports = snanmskrange;