@stdlib/ndarray-empty-like NPM

emptyLike

Create an uninitialized ndarray having the same shape and data type as a provided ndarray.

Installation

npm install @stdlib/ndarray-empty-like

Usage

var emptyLike = require( '@stdlib/ndarray-empty-like' );

emptyLike( x[, options] )

Creates an uninitialized ndarray having the same shape and data type as a provided ndarray.

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

var x = zeros( [ 2, 2 ] );
// returns <ndarray>

var y = emptyLike( x );
// returns <ndarray>

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

var dt = y.dtype;
// returns 'float64'

The function supports the following options:

dtype: output ndarray data type. Overrides the input ndarray's inferred data type.
shape: output ndarray shape. Overrides the input ndarray's inferred shape.
order: specifies whether the output ndarray should be 'row-major' (C-style) or 'column-major' (Fortran-style). Overrides the input ndarray's inferred order.
mode: specifies how to handle indices which exceed array dimensions (see ndarray). Default: 'throw'.
submode: a mode array which specifies for each dimension how to handle subscripts which exceed array dimensions (see ndarray). If provided fewer modes than dimensions, the constructor recycles modes using modulo arithmetic. Default: [ options.mode ].

To override either the dtype, shape, or order, specify the corresponding option. For example, to override the inferred data type,

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

var x = zeros( [ 2, 2 ] );
// returns <ndarray>

var dt = x.dtype;
// returns 'float64'

var y = emptyLike( x, {
    'dtype': 'int32'
});
// returns <ndarray>

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

dt = y.dtype;
// returns 'int32'

Notes

If the resolved output data type is 'generic', the function always returns a zero-filled array.
For returned ndarrays whose underlying memory is not initialized, memory contents are unknown and may contain sensitive data.

Examples

var dtypes = require( '@stdlib/ndarray-dtypes' );
var zeros = require( '@stdlib/ndarray-zeros' );
var emptyLike = require( '@stdlib/ndarray-empty-like' );

// Get a list of data types:
var dt = dtypes();

// Generate uninitialized arrays...
var x;
var y;
var i;
for ( i = 0; i < dt.length; i++ ) {
    x = zeros( [ 2, 2 ], {
        'dtype': dt[ i ]
    });
    y = emptyLike( x );
    console.log( y.data );
}

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.