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README.md

empty

Create an uninitialized ndarray having a specified shape and data type.

Usage

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

empty( shape[, options] )

Creates an uninitialized ndarray having a specified shape and data type.

var getShape = require( '@stdlib/ndarray/shape' );
var getDType = require( '@stdlib/ndarray/dtype' );

var arr = empty( [ 2, 2 ] );
// returns <ndarray>

var sh = getShape( arr );
// returns [ 2, 2 ]

var dt = String( getDType( arr ) );
// returns 'float64'

The specified output ndarray shape may be either an array-like object or an integer value.

var getShape = require( '@stdlib/ndarray/shape' );
var getDType = require( '@stdlib/ndarray/dtype' );

var arr = empty( 2 );
// returns <ndarray>

var sh = getShape( arr );
// returns [ 2 ]

var dt = String( getDType( arr ) );
// returns 'float64'

The function accepts the following options:

  • dtype: underlying data type. Default: 'float64'.
  • order: specifies whether an ndarray is 'row-major' (C-style) or 'column-major' (Fortran-style). Default: 'row-major'.
  • 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 ].

By default, the function returns an ndarray having a float64 data type. To specify an alternative data type, provide a dtype option.

var getShape = require( '@stdlib/ndarray/shape' );
var getDType = require( '@stdlib/ndarray/dtype' );

var arr = empty( [ 2, 2 ], {
    'dtype': 'float32'
});
// returns <ndarray>

var sh = getShape( arr );
// returns [ 2, 2 ]

var dt = String( getDType( arr ) );
// returns 'float32'

Notes

  • If the dtype option is 'generic', the function always returns a zero-filled ndarray.
  • 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 ndarray2array = require( '@stdlib/ndarray/to-array' );
var empty = require( '@stdlib/ndarray/empty' );

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

// Generate uninitialized arrays...
var arr;
var i;
for ( i = 0; i < dt.length; i++ ) {
    arr = empty( [ 2, 2 ], {
        'dtype': dt[ i ]
    });
    console.log( ndarray2array( arr ) );
}

See Also