time-to-botec

Benchmark sampling in different programming languages
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copy_ndarray.js (3457B)

      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 // FUNCTIONS //
     22 
     23 /**
     24 * Returns an ndarray buffer element.
     25 *
     26 * @private
     27 * @param {Collection} buf - data buffer
     28 * @param {NonNegativeInteger} idx - element index
     29 * @returns {*} element
     30 */
     31 function getIndexed( buf, idx ) {
     32 	return buf[ idx ];
     33 }
     34 
     35 /**
     36 * Returns an ndarray buffer element using an accessor method.
     37 *
     38 * @private
     39 * @param {Collection} buf - data buffer
     40 * @param {NonNegativeInteger} idx - element index
     41 * @returns {*} element
     42 */
     43 function getAccessor( buf, idx ) {
     44 	return buf.get( idx );
     45 }
     46 
     47 /**
     48 * Sets an ndarray buffer element.
     49 *
     50 * @private
     51 * @param {Collection} buf - data buffer
     52 * @param {NonNegativeInteger} idx - element index
     53 * @param {*} value - value to set
     54 */
     55 function setIndexed( buf, idx, value ) {
     56 	buf[ idx ] = value;
     57 }
     58 
     59 /**
     60 * Sets an ndarray buffer element using an accessor method.
     61 *
     62 * @private
     63 * @param {Collection} buf - data buffer
     64 * @param {NonNegativeInteger} idx - element index
     65 * @param {*} value - value to set
     66 */
     67 function setAccessor( buf, idx, value ) {
     68 	buf.set( value, idx );
     69 }
     70 
     71 
     72 // MAIN //
     73 
     74 /**
     75 * Copies ndarray meta-data to an object likely to have the same "hidden" shape.
     76 *
     77 * ## Notes
     78 *
     79 * -   This function is intended as a potential performance optimization. In V8, for example, even if two objects share common properties, if those properties were added in different orders or if one object has additional properties not shared by the other object, then those objects will have different "hidden" classes. If a function is provided many objects having different "shapes", some JavaScript VMs (e.g., V8) will consider the function "megamorphic" and fail to perform various runtime optimizations. Accordingly, the intent of this function is to standardize the "shape" of the object holding ndarray meta data to ensure that loop iteration functions are provided consistent argument "shapes".
     80 *
     81 * @private
     82 * @param {Object} x - object containing ndarray meta data
     83 * @param {string} x.dtype - data type
     84 * @param {Collection} x.data - data buffer
     85 * @param {NonNegativeIntegerArray} x.shape - dimensions
     86 * @param {IntegerArray} x.strides - stride lengths
     87 * @param {NonNegativeInteger} x.offset - index offset
     88 * @param {string} x.order - specifies whether `x` is row-major (C-style) or column-major (Fortran-style)
     89 * @returns {Object} object containing ndarray meta data
     90 */
     91 function copy( x ) {
     92 	var xbuf;
     93 	var bool;
     94 
     95 	xbuf = x.data;
     96 	bool = Boolean( xbuf.get && xbuf.set ); // Note: intentional weak check, as don't explicitly check for functions for (perhaps marginally) better performance.
     97 	return {
     98 		'dtype': x.dtype,
     99 		'data': xbuf,
    100 		'shape': x.shape,
    101 		'strides': x.strides,
    102 		'offset': x.offset,
    103 		'order': x.order,
    104 		'accessors': bool,
    105 		'getter': ( bool ) ? getAccessor : getIndexed,
    106 		'setter': ( bool ) ? setAccessor : setIndexed
    107 	};
    108 }
    109 
    110 
    111 // EXPORTS //
    112 
    113 module.exports = copy;