## Usage ```javascript var toRotl90 = require( '@stdlib/ndarray/to-rotl90' ); ``` #### toRotl90( x, k ) Returns a new [`ndarray`][@stdlib/ndarray/ctor] where a matrix (or a stack of matrices) is rotated 90 degrees counterclockwise. ```javascript var array = require( '@stdlib/ndarray/array' ); var x = array( [ [ 1.0, 2.0, 3.0 ], [ 4.0, 5.0, 6.0 ] ] ); // returns [ [ 1.0, 2.0, 3.0 ], [ 4.0, 5.0, 6.0 ] ] var y = toRotl90( x, 1 ); // returns [ [ 3.0, 6.0 ], [ 2.0, 5.0 ], [ 1.0, 4.0 ] ] ``` The function accepts the following arguments: - **x**: input [`ndarray`][@stdlib/ndarray/ctor]. - **k**: number of times to rotate by 90 degrees. Positive values rotate counterclockwise. Negative values rotate clockwise.

## Notes - If `k > 0`, the function rotates the matrix counterclockwise. - If `k < 0`, the function rotates the matrix clockwise. - If provided an [`ndarray`][@stdlib/ndarray/ctor] with fewer than two dimensions, the function does not perform a rotation and simply returns a copy of the input [`ndarray`][@stdlib/ndarray/ctor].

## Examples ```javascript var uniform = require( '@stdlib/random/uniform' ); var ndarray2array = require( '@stdlib/ndarray/to-array' ); var toRotl90 = require( '@stdlib/ndarray/to-rotl90' ); var x = uniform( [ 3, 3, 3 ], -10.0, 10.0 ); console.log( ndarray2array( x ) ); var y = toRotl90( x, 1 ); console.log( ndarray2array( y ) ); ```