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rot90

Return a read-only view of an input ndarray rotated 90 degrees in a specified plane.

Usage

var rot90 = require( '@stdlib/ndarray/rot90' );

rot90( x[, options] )

Returns a read-only view of an input ndarray rotated 90 degrees in a specified plane.

var array = require( '@stdlib/ndarray/array' );

var x = array( [ [ 1.0, 2.0 ], [ 3.0, 4.0 ] ] );
// returns <ndarray>[ [ 1.0, 2.0 ], [ 3.0, 4.0 ] ]

var y = rot90( x );
// returns <ndarray>[ [ 2.0, 4.0 ], [ 1.0, 3.0 ] ]

The function accepts the following arguments:

  • x: input ndarray.
  • options: function options.

The function accepts the following options:

  • k: number of times to rotate by 90 degrees. Positive values rotate counterclockwise. Negative values rotate clockwise. Default: 1.
  • dims: dimension indices defining the plane of rotation. Must contain exactly two unique dimension indices. If a dimension index is provided as an integer less than zero, the dimension index is resolved relative to the last dimension, with the last dimension corresponding to the value -1. Default: [-2, -1].

Notes

  • If options.k > 0, the function rotates the plane from the first specified dimension toward the second specified dimension. This means that, for a two-dimensional ndarray and options.dims = [0, 1], the function rotates the plane counterclockwise.
  • If options.k < 0, the function rotates the plane from the second specified dimension toward the first specified dimension. This means that, for a two-dimensional ndarray and options.dims = [0, 1], the function rotates the plane clockwise.
  • Each provided dimension index must reside on the interval [-ndims, ndims-1].

Examples

var uniform = require( '@stdlib/random/uniform' );
var ndarray2array = require( '@stdlib/ndarray/to-array' );
var rot90 = require( '@stdlib/ndarray/rot90' );

var x = uniform( [ 3, 3, 3 ], -10.0, 10.0 );
console.log( ndarray2array( x ) );

var y = rot90( x );
console.log( ndarray2array( y ) );