120 lines
2.7 KiB
JavaScript
120 lines
2.7 KiB
JavaScript
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/**
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* @license Apache-2.0
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*
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* Copyright (c) 2018 The Stdlib Authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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'use strict';
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// MODULES //
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var Int32Array = require( '@stdlib/array/int32' );
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var Float64Array = require( '@stdlib/array/float64' );
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var setReadOnly = require( '@stdlib/utils/define-nonenumerable-read-only-property' );
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// MAIN //
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/**
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* Returns a Matrix instance.
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*
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* @private
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* @constructor
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* @param {NumberArray} shape - matrix dimensions/shape
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* @param {string} [dtype="float64"] - matrix data type
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* @returns {Matrix} Matrix instance
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*/
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function matrix() {
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var dtype;
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var ndims;
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var shape;
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var data;
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var len;
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var mat;
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var i;
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if ( arguments.length === 1 ) {
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shape = arguments[ 0 ];
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}
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else if ( arguments.length === 2 ) {
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shape = arguments[ 0 ];
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dtype = arguments[ 1 ];
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}
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ndims = shape.length;
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len = 1;
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for ( i = 0; i < ndims; i++ ) {
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len *= shape[ i ];
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}
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// Initialize a zero-filled typed array...
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if ( dtype === 'int32' ) {
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data = new Int32Array( len );
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}
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else {
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data = new Float64Array( len );
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}
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// Return a new Matrix instance:
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mat = {};
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mat.dtype = dtype;
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mat.shape = shape;
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mat.strides = [ shape[1], 1 ];
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mat.offset = 0;
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mat.ndims = shape.length;
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mat.length = data.length;
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mat.nbytes = data.byteLength;
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mat.data = data;
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setReadOnly( mat, 'get', get );
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setReadOnly( mat, 'set', set );
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return mat;
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/**
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* Returns a matrix element based on the provided row and column indices.
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*
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* @private
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* @param {integer} i - row index
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* @param {integer} j - column index
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* @returns {(number|undefined)} matrix element
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*/
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function get( i, j ) {
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/* eslint-disable no-invalid-this */
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var idx = this.offset + ( i*this.strides[0] ) + ( j*this.strides[1] );
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return this.data[ idx ];
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}
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/**
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* Sets a matrix element based on the provided row and column indices.
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*
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* @private
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* @param {integer} i - row index
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* @param {integer} j - column index
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* @param {number} v - value to set
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* @returns {Matrix} Matrix instance
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*/
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function set( i, j, v ) {
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/* eslint-disable no-invalid-this */
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i = this.offset + ( i*this.strides[0] ) + ( j*this.strides[1] );
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if ( i >= 0 ) {
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this.data[ i ] = v;
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}
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return this;
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}
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}
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// EXPORTS //
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module.exports = matrix;
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