matrix.js (2739B)
1 /** 2 * @license Apache-2.0 3 * 4 * Copyright (c) 2018 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 Int32Array = require( '@stdlib/array/int32' ); 24 var Float64Array = require( '@stdlib/array/float64' ); 25 var setReadOnly = require( '@stdlib/utils/define-nonenumerable-read-only-property' ); 26 27 28 // MAIN // 29 30 /** 31 * Returns a Matrix instance. 32 * 33 * @private 34 * @constructor 35 * @param {NumberArray} shape - matrix dimensions/shape 36 * @param {string} [dtype="float64"] - matrix data type 37 * @returns {Matrix} Matrix instance 38 */ 39 function matrix() { 40 var dtype; 41 var ndims; 42 var shape; 43 var data; 44 var len; 45 var mat; 46 var i; 47 48 if ( arguments.length === 1 ) { 49 shape = arguments[ 0 ]; 50 } 51 else if ( arguments.length === 2 ) { 52 shape = arguments[ 0 ]; 53 dtype = arguments[ 1 ]; 54 } 55 ndims = shape.length; 56 len = 1; 57 for ( i = 0; i < ndims; i++ ) { 58 len *= shape[ i ]; 59 } 60 // Initialize a zero-filled typed array... 61 if ( dtype === 'int32' ) { 62 data = new Int32Array( len ); 63 } 64 else { 65 data = new Float64Array( len ); 66 } 67 68 // Return a new Matrix instance: 69 mat = {}; 70 mat.dtype = dtype; 71 mat.shape = shape; 72 mat.strides = [ shape[1], 1 ]; 73 mat.offset = 0; 74 mat.ndims = shape.length; 75 mat.length = data.length; 76 mat.nbytes = data.byteLength; 77 mat.data = data; 78 79 setReadOnly( mat, 'get', get ); 80 setReadOnly( mat, 'set', set ); 81 return mat; 82 83 /** 84 * Returns a matrix element based on the provided row and column indices. 85 * 86 * @private 87 * @param {integer} i - row index 88 * @param {integer} j - column index 89 * @returns {(number|undefined)} matrix element 90 */ 91 function get( i, j ) { 92 /* eslint-disable no-invalid-this */ 93 var idx = this.offset + ( i*this.strides[0] ) + ( j*this.strides[1] ); 94 return this.data[ idx ]; 95 } 96 97 /** 98 * Sets a matrix element based on the provided row and column indices. 99 * 100 * @private 101 * @param {integer} i - row index 102 * @param {integer} j - column index 103 * @param {number} v - value to set 104 * @returns {Matrix} Matrix instance 105 */ 106 function set( i, j, v ) { 107 /* eslint-disable no-invalid-this */ 108 i = this.offset + ( i*this.strides[0] ) + ( j*this.strides[1] ); 109 if ( i >= 0 ) { 110 this.data[ i ] = v; 111 } 112 return this; 113 } 114 } 115 116 117 // EXPORTS // 118 119 module.exports = matrix;