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 | 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 | /**
* @license Apache-2.0
*
* Copyright (c) 2026 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 getDType = require( '@stdlib/ndarray/base/dtype' );
var getShape = require( '@stdlib/ndarray/base/shape' );
var getStrides = require( '@stdlib/ndarray/base/strides' );
var getOffset = require( '@stdlib/ndarray/base/offset' );
var getOrder = require( '@stdlib/ndarray/base/order' );
var getData = require( '@stdlib/ndarray/base/data-buffer' );
// MAIN //
/**
* Rotates a matrix (or a stack of matrices) 90 degrees clockwise.
*
* @param {ndarray} x - input array
* @param {integer} k - number of times to rotate by 90 degrees
* @param {boolean} writable - boolean indicating whether the returned ndarray should be writable
* @returns {ndarray} ndarray view
*
* @example
* var array = require( '@stdlib/ndarray/array' );
*
* var x = array( [ [ 1, 2 ], [ 3, 4 ] ] );
* // returns <ndarray>[ [ 1, 2 ], [ 3, 4 ] ]
*
* var y = rotr90( x, 1, false );
* // returns <ndarray>[ [ 3, 1 ], [ 4, 2 ] ]
*/
function rotr90( x, k, writable ) {
var offset;
var sh;
var st;
var sm;
var sn;
var M;
var N;
var d;
sh = getShape( x, true );
d = sh.length;
st = getStrides( x, true );
offset = getOffset( x );
if ( d >= 2 ) {
// Normalize `k` to the interval [0, 3]:
k %= 4;
if ( k < 0 ) {
k += 4;
}
// Cache the original shape and stride values for the last two dimensions:
M = sh[ d-2 ];
N = sh[ d-1 ];
sm = st[ d-2 ];
sn = st[ d-1 ];
// Case: rotate 90 deg clockwise
if ( k === 1 ) {
sh[ d-2 ] = N;
sh[ d-1 ] = M;
st[ d-2 ] = sn;
st[ d-1 ] = -sm;
offset += ( M - 1 ) * sm;
}
// Case: rotate 180 deg clockwise (i.e., reverse both dimensions)
else if ( k === 2 ) {
st[ d-2 ] = -sm;
st[ d-1 ] = -sn;
offset += ( ( M - 1 ) * sm ) + ( ( N - 1 ) * sn );
}
// Case: rotate 270 deg clockwise
else if ( k === 3 ) {
sh[ d-2 ] = N;
sh[ d-1 ] = M;
st[ d-2 ] = -sn;
st[ d-1 ] = sm;
offset += ( N - 1 ) * sn;
}
}
return new x.constructor( getDType( x ), getData( x ), sh, st, offset, getOrder( x ), { // eslint-disable-line max-len
'readonly': !writable
});
}
// EXPORTS //
module.exports = rotr90;
|