flipud

Return a view of an input ndarray in which the order of elements along the second-to-last dimension is reversed.

Installation

npm install @stdlib/ndarray-base-flipud

Usage

var flipud = require( '@stdlib/ndarray-base-flipud' );

flipud( x, writable )

Returns a view of an input ndarray in which the order of elements along the second-to-last dimension is reversed.

var ndarray = require( '@stdlib/ndarray-ctor' );
var ndarray2array = require( '@stdlib/ndarray-to-array' );

var buffer = [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ];
var shape = [ 3, 2 ];
var strides = [ 2, 1 ];
var offset = 0;

var x = ndarray( 'generic', buffer, shape, strides, offset, 'row-major' );
// returns <ndarray>

var sh = x.shape;
// returns [ 3, 2 ]

var arr = ndarray2array( x );
// returns [ [ 1.0, 2.0 ], [ 3.0, 4.0 ], [ 5.0, 6.0 ] ]

var y = flipud( x, false );
// returns <ndarray>

sh = y.shape;
// returns [ 3, 2 ]

arr = ndarray2array( y );
// returns [ [ 5.0, 6.0 ], [ 3.0, 4.0 ], [ 1.0, 2.0 ] ]

The function accepts the following arguments:

• x: input ndarray.
• writable: boolean indicating whether a returned ndarray should be writable.

Notes

• If provided a zero-dimensional ndarray, as the ndarray has no dimensions to reverse, the function simply returns a new view of the input ndarray. Similarly, if provided a one-dimensional ndarray, as the ndarray has only one dimension, the function simply returns a new view of the input ndarray.
• The writable parameter only applies to ndarray constructors supporting read-only instances.

Examples

var array = require( '@stdlib/ndarray-array' );
var ndarray2array = require( '@stdlib/ndarray-to-array' );
var zeroTo = require( '@stdlib/array-base-zero-to' );
var flipud = require( '@stdlib/ndarray-base-flipud' );

// Create a linear ndarray buffer:
var buf = zeroTo( 16 );

// Create a three-dimensional ndarray:
var x = array( buf, {
    'shape': [ 2, 4, 2 ]
});

// Reverse the order of second-to-last dimension:
var y = flipud( x, false );
// returns <ndarray>

var a = ndarray2array( y );
// returns [ [ [ 6, 7 ], [ 4, 5 ], [ 2, 3 ], [ 0, 1 ] ], [ [ 14, 15 ], [ 12, 13 ], [ 10, 11 ], [ 8, 9 ] ] ]

Notice

This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.

Community

License

See LICENSE.

Copyright

Copyright © 2016-2024. The Stdlib Authors.