ndarray.js (2474B)
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 // MAIN // 22 23 /** 24 * Applies a unary callback to elements in a strided input array according to elements in a strided mask array and assigns results to elements in a strided output array. 25 * 26 * @param {ArrayLikeObject<Collection>} arrays - array-like object containing one input array, a mask array, and one output array 27 * @param {NonNegativeIntegerArray} shape - array-like object containing a single element, the number of indexed elements 28 * @param {IntegerArray} strides - array-like object containing the stride lengths for the strided arrays 29 * @param {NonNegativeIntegerArray} offsets - array-like object containing the starting indices (i.e., index offsets) for the strided arrays 30 * @param {Callback} fcn - unary callback 31 * @returns {void} 32 * 33 * @example 34 * var Float64Array = require( '@stdlib/array/float64' ); 35 * var Uint8Array = require( '@stdlib/array/uint8' ); 36 * 37 * function scale( x ) { 38 * return x * 10.0; 39 * } 40 * 41 * var x = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0 ] ); 42 * var m = new Uint8Array( [ 0, 0, 1, 0, 0 ] ); 43 * var y = new Float64Array( x.length ); 44 * 45 * var shape = [ x.length ]; 46 * var strides = [ 1, 1, 1 ]; 47 * var offsets = [ 0, 0, 0 ]; 48 * 49 * mskunary( [ x, m, y ], shape, strides, offsets, scale ); 50 * 51 * console.log( y ); 52 * // => <Float64Array>[ 10.0, 20.0, 0.0, 40.0, 50.0 ] 53 */ 54 function mskunary( arrays, shape, strides, offsets, fcn ) { 55 var sx; 56 var sm; 57 var sy; 58 var ix; 59 var im; 60 var iy; 61 var x; 62 var m; 63 var y; 64 var N; 65 var i; 66 67 N = shape[ 0 ]; 68 if ( N <= 0 ) { 69 return; 70 } 71 ix = offsets[ 0 ]; 72 im = offsets[ 1 ]; 73 iy = offsets[ 2 ]; 74 sx = strides[ 0 ]; 75 sm = strides[ 1 ]; 76 sy = strides[ 2 ]; 77 x = arrays[ 0 ]; 78 m = arrays[ 1 ]; 79 y = arrays[ 2 ]; 80 for ( i = 0; i < N; i++ ) { 81 if ( m[ im ] === 0 ) { 82 y[ iy ] = fcn( x[ ix ] ); 83 } 84 ix += sx; 85 im += sm; 86 iy += sy; 87 } 88 } 89 90 91 // EXPORTS // 92 93 module.exports = mskunary;