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.

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 );