nd.js (3790B)
1 /** 2 * @license Apache-2.0 3 * 4 * Copyright (c) 2021 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 numel = require( './../../../base/numel' ); 24 var vind2bind = require( './../../../base/vind2bind' ); 25 26 27 // VARIABLES // 28 29 var MODE = 'throw'; 30 31 32 // MAIN // 33 34 /** 35 * Applies a unary callback to elements in an n-dimensional input ndarray and assigns results to elements in an equivalently shaped output ndarray. 36 * 37 * @private 38 * @param {Object} x - object containing input ndarray meta data 39 * @param {string} x.dtype - data type 40 * @param {Collection} x.data - data buffer 41 * @param {NonNegativeIntegerArray} x.shape - dimensions 42 * @param {IntegerArray} x.strides - stride lengths 43 * @param {NonNegativeInteger} x.offset - index offset 44 * @param {string} x.order - specifies whether `x` is row-major (C-style) or column-major (Fortran-style) 45 * @param {Object} y - object containing output ndarray meta data 46 * @param {string} y.dtype - data type 47 * @param {Collection} y.data - data buffer 48 * @param {NonNegativeIntegerArray} y.shape - dimensions 49 * @param {IntegerArray} y.strides - stride lengths 50 * @param {NonNegativeInteger} y.offset - index offset 51 * @param {string} y.order - specifies whether `y` is row-major (C-style) or column-major (Fortran-style) 52 * @param {Callback} fcn - unary callback 53 * @returns {void} 54 * 55 * @example 56 * var Float64Array = require( '@stdlib/array/float64' ); 57 * 58 * function scale( x ) { 59 * return x * 10.0; 60 * } 61 * 62 * // Create data buffers: 63 * var xbuf = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] ); 64 * var ybuf = new Float64Array( 4 ); 65 * 66 * // Define the shape of the input and output arrays: 67 * var shape = [ 2, 2 ]; 68 * 69 * // Define the array strides: 70 * var sx = [ 4, 1 ]; 71 * var sy = [ 2, 1 ]; 72 * 73 * // Define the index offsets: 74 * var ox = 1; 75 * var oy = 0; 76 * 77 * // Create the input and output ndarray-like objects: 78 * var x = { 79 * 'dtype': 'float64', 80 * 'data': xbuf, 81 * 'shape': shape, 82 * 'strides': sx, 83 * 'offset': ox, 84 * 'order': 'row-major' 85 * }; 86 * var y = { 87 * 'dtype': 'float64', 88 * 'data': ybuf, 89 * 'shape': shape, 90 * 'strides': sy, 91 * 'offset': oy, 92 * 'order': 'row-major' 93 * }; 94 * 95 * // Apply the unary function: 96 * unarynd( x, y, scale ); 97 * 98 * console.log( y.data ); 99 * // => <Float64Array>[ 20.0, 30.0, 60.0, 70.0 ] 100 */ 101 function unarynd( x, y, fcn ) { 102 var xbuf; 103 var ybuf; 104 var ordx; 105 var ordy; 106 var len; 107 var sh; 108 var sx; 109 var sy; 110 var ox; 111 var oy; 112 var ix; 113 var iy; 114 var i; 115 116 sh = x.shape; 117 118 // Compute the total number of elements over which to iterate: 119 len = numel( sh ); 120 121 // Cache references to the input and output ndarray data buffers: 122 xbuf = x.data; 123 ybuf = y.data; 124 125 // Cache references the respective stride arrays: 126 sx = x.strides; 127 sy = y.strides; 128 129 // Cache the indices of the first indexed elements in the respective ndarrays: 130 ox = x.offset; 131 oy = y.offset; 132 133 // Cache the respective array orders: 134 ordx = x.order; 135 ordy = y.order; 136 137 // Iterate over each element based on the linear **view** index, regardless as to how the data is stored in memory... 138 for ( i = 0; i < len; i++ ) { 139 ix = vind2bind( sh, sx, ox, ordx, i, MODE ); 140 iy = vind2bind( sh, sy, oy, ordy, i, MODE ); 141 ybuf[ iy ] = fcn( xbuf[ ix ] ); 142 } 143 } 144 145 146 // EXPORTS // 147 148 module.exports = unarynd;