Press n or j to go to the next uncovered block, b, p or k for the previous block.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 | 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 10x 10x 53x 10x 10x 33x 33x 33x 53x 10x 10x 23x 23x 53x 66x 66x 23x 23x 53x 51x 51x 12x 12x 12x 39x 39x 51x 3x 3x 51x 6x 6x 51x 25x 51x 3x 3x 5x 2x 2x 2x 51x 12x 12x 12x 53x 1x 1x 1x 1x 1x | /**
* @license Apache-2.0
*
* Copyright (c) 2023 The Stdlib Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
'use strict';
// MODULES //
var isndarrayLike = require( '@stdlib/assert/is-ndarray-like' );
var isCollection = require( '@stdlib/assert/is-collection' );
var isNonNegativeInteger = require( '@stdlib/assert/is-nonnegative-integer' ).isPrimitive;
var copy = require( '@stdlib/array/base/copy-indexed' );
var getDType = require( '@stdlib/ndarray/dtype' );
var getShape = require( '@stdlib/ndarray/shape' );
var getStrides = require( '@stdlib/ndarray/strides' );
var getOffset = require( '@stdlib/ndarray/offset' );
var getOrder = require( '@stdlib/ndarray/order' );
var getData = require( '@stdlib/ndarray/data-buffer' );
var format = require( '@stdlib/string/format' );
// MAIN //
/**
* Broadcasts an ndarray to a specified shape.
*
* ## Notes
*
* - The returned array is a **read-only** view on the input array data buffer. The view is typically **not** contiguous. As more than one element of a returned view may refer to the same memory location, writing to the input array may affect multiple elements. If you need to write to the input array, copy the input array before broadcasting.
*
* @param {ndarray} x - input array
* @param {NonNegativeIntegerArray} shape - desired shape
* @throws {TypeError} first argument must be an ndarray
* @throws {TypeError} second argument must be an array of nonnegative integers
* @throws {Error} input array cannot have more dimensions than the desired shape
* @throws {Error} input array dimension sizes must be `1` or equal to the corresponding dimension in the provided shape
* @throws {Error} input array and desired shape must be broadcast compatible
* @returns {ndarray} broadcasted array
*
* @example
* var array = require( '@stdlib/ndarray/array' );
*
* var x = array( [ [ 1, 2 ], [ 3, 4 ] ] );
* // returns <ndarray>
*
* var shx = x.shape;
* // returns [ 2, 2 ]
*
* var y = broadcastArray( x, [ 3, 2, 2 ] );
* // returns <ndarray>
*
* var shy = y.shape;
* // returns [ 3, 2, 2 ]
*
* var v = y.get( 0, 0, 0 );
* // returns 1
*
* v = y.get( 0, 0, 1 );
* // returns 2
*
* v = y.get( 1, 0, 0 );
* // returns 1
*
* v = y.get( 1, 1, 0 );
* // returns 3
*
* v = y.get( 2, 0, 0 );
* // returns 1
*
* v = y.get( 2, 1, 1 );
* // returns 4
*
* @example
* var array = require( '@stdlib/ndarray/array' );
*
* var x = array( [ [ 1, 2 ], [ 3, 4 ] ] );
* // returns <ndarray>
*
* var y = broadcastArray( x, [ 3, 2 ] );
* // throws <Error>
*/
function broadcastArray( x, shape ) {
var strides;
var dim;
var sh;
var st;
var N;
var M;
var d;
var i;
var j;
if ( !isndarrayLike( x ) ) {
throw new TypeError( format( 'invalid argument. First argument must be an ndarray. Value: `%s`.', x ) );
}
if ( !isCollection( shape ) ) {
throw new TypeError( format( 'invalid argument. Second argument must be an array of nonnegative integers. Value: `%s`.', shape ) );
}
N = shape.length;
sh = getShape( x );
M = sh.length;
if ( N < M ) {
throw new Error( 'invalid argument. Cannot broadcast an array to a shape having fewer dimensions. Arrays can only be broadcasted to shapes having the same or more dimensions.' );
}
// Initialize a strides array...
strides = [];
for ( i = 0; i < N; i++ ) {
strides.push( 0 );
}
// Determine the output array strides...
st = getStrides( x );
for ( i = N-1; i >= 0; i-- ) {
j = M - N + i;
if ( j < 0 ) {
// Prepended singleton dimension; stride is zero...
continue;
}
d = sh[ j ];
dim = shape[ i ];
if ( !isNonNegativeInteger( dim ) ) {
throw new TypeError( format( 'invalid argument. Second argument must be an array of nonnegative integers. Value: `%s`.', '[' + shape.join( ',' ) + ']' ) );
}
if ( dim !== 0 && dim < d ) {
throw new Error( format( 'invalid argument. Input array cannot be broadcast to the specified shape, as the specified shape has a dimension whose size is less than the size of the corresponding dimension in the input array. Array shape: (%s). Desired shape: (%s). Dimension: %u.', copy( sh ).join( ', ' ), copy( shape ).join( ', ' ), i ) );
}
if ( d === dim ) {
strides[ i ] = st[ j ];
} else if ( d === 1 ) {
// In order to broadcast dimensions, we set the stride for that dimension to zero...
strides[ i ] = 0;
} else {
// At this point, we know that `dim > d` and that `d` does not equal `1` (e.g., `dim=3` and `d=2`); in which case, the shapes are considered incompatible (even for desired shapes which are multiples of array dimensions, as might be desired when "tiling" an array; e.g., `dim=4` and `d=2`)...
throw new Error( format( 'invalid argument. Input array and the specified shape are broadcast incompatible. Array shape: (%s). Desired shape: (%s). Dimension: %u.', copy( sh ).join( ', ' ), copy( shape ).join( ', ' ), i ) );
}
}
return new x.constructor( getDType( x ), getData( x ), copy( shape ), strides, getOffset( x ), getOrder( x ), { // eslint-disable-line max-len
'readonly': true
});
}
// EXPORTS //
module.exports = broadcastArray;
|