map4d

Apply a function to elements in a four-dimensional nested input array and assign results to elements in a new four-dimensional nested output array.

Installation

npm install @stdlib/array-base-map4d

Usage

var map4d = require( '@stdlib/array-base-map4d' );

map4d( x, shape, fcn[, thisArg] )

Applies a function to elements in a four-dimensional nested input array and assigns results to elements in a new four-dimensional nested output array.

var naryFunction = require( '@stdlib/utils-nary-function' );
var abs = require( '@stdlib/math-base-special-abs' );

var x = [ [ [ [ -1.0, -2.0 ], [ -3.0, -4.0 ] ] ] ];
var shape = [ 1, 1, 2, 2 ];

var y = map4d( x, shape, naryFunction( abs, 1 ) );
// returns [ [ [ [ 1.0, 2.0 ], [ 3.0, 4.0 ] ] ] ]

The function accepts the following arguments:

• x: input nested array.
• shape: array shape.
• fcn: function to apply.
• thisArg: applied function execution context (optional).

To set the applied function's execution context, provide a thisArg.

function fcn( x ) {
    this.count += 1;
    return x;
}

var x = [ [ [ [ 1.0, 2.0 ], [ 3.0, 4.0 ] ] ] ];
var shape = [ 1, 1, 2, 2 ];

var ctx = {
    'count': 0
};

var y = map4d( x, shape, fcn, ctx );
// returns [ [ [ [ 1.0, 2.0 ], [ 3.0, 4.0 ] ] ] ]

var v = ctx.count;
// returns 4

map4d.assign( x, y, shape, fcn[, thisArg] )

Applies a function to elements in a four-dimensional nested input array and assigns results to elements in a four-dimensional nested output array.

var naryFunction = require( '@stdlib/utils-nary-function' );
var zeros4d = require( '@stdlib/array-base-zeros4d' );
var abs = require( '@stdlib/math-base-special-abs' );

var x = [ [ [ [ -1.0, -2.0 ], [ -3.0, -4.0 ] ] ] ];
var shape = [ 1, 1, 2, 2 ];

var y = zeros4d( shape );

var out = map4d.assign( x, y, shape, naryFunction( abs, 1 ) );
// returns [ [ [ [ 1.0, 2.0 ], [ 3.0, 4.0 ] ] ] ]

var bool = ( out === y );
// returns true

The function accepts the following arguments:

• x: input nested array.
• y: output nested array.
• shape: array shape.
• fcn: function to apply.
• thisArg: applied function execution context (optional).

The function assumes that the input and output arrays have the same shape.

Examples

var discreteUniform = require( '@stdlib/random-base-discrete-uniform' ).factory;
var filled4dBy = require( '@stdlib/array-base-filled4d-by' );
var naryFunction = require( '@stdlib/utils-nary-function' );
var abs = require( '@stdlib/math-base-special-abs' );
var map4d = require( '@stdlib/array-base-map4d' );

var shape = [ 1, 3, 3, 3 ];

var x = filled4dBy( shape, discreteUniform( -100, 100 ) );
console.log( x );

var y = map4d( x, shape, naryFunction( abs, 1 ) );
console.log( y );

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.