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dispatch

Dispatch to a native add-on applying a unary function to an input ndarray.

Installation

npm install @stdlib/ndarray-base-unary-addon-dispatch

Alternatively,

• To load the package in a website via a script tag without installation and bundlers, use the ES Module available on the esm branch (see README).
• If you are using Deno, visit the deno branch (see README for usage intructions).
• For use in Observable, or in browser/node environments, use the Universal Module Definition (UMD) build available on the umd branch (see README).

The branches.md file summarizes the available branches and displays a diagram illustrating their relationships.

To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.

Usage

var dispatch = require( '@stdlib/ndarray-base-unary-addon-dispatch' );

dispatch( addon, fallback )

Returns a function which dispatches to a native add-on applying a unary function to an input ndarray.

var array = require( '@stdlib/ndarray-array' );
var zeros = require( '@stdlib/ndarray-zeros' );
var dispatch = require( '@stdlib/ndarray-base-unary-addon-dispatch' );

function addon( x, metaX, y, metaY ) {
    // Call into native add-on...
}

function fallback( x, y ) {
    // Fallback JavaScript implementation...
}

// Create a dispatch function:
var f = dispatch( addon, fallback );

// ...

// Invoke the dispatch function with ndarray arguments:
var x = array( [ [ 1, 2], [ 3, 4 ] ] );
var y = zeros( [ 2, 2 ] );
f( x, y );

The returned function has the following signature:

f( x, y )

where

• x: input ndarray.
• y: output ndarray.

The addon function should have the following signature:

f( xbuf, metaX, ybuf, metaY )

where

• xbuf: input ndarray data buffer.
• metaX: serialized input ndarray meta data.
• ybuf: output ndarray data buffer.
• metaY: serialized output ndarray meta data.

The fallback function should have the following signature:

f( x, y )

where

• x: input ndarray.
• y: output ndarray.

Notes

• To determine whether to dispatch to the addon function, the returned dispatch function checks whether the underlying ndarray data buffers are typed arrays. If the data buffers are typed arrays, the dispatch function invokes the addon function; otherwise, the dispatch function invokes the fallback function.

Examples

var array = require( '@stdlib/ndarray-array' );
var zeros = require( '@stdlib/ndarray-zeros' );
var ndarray2array = require( '@stdlib/ndarray-to-array' );
var dispatch = require( '@stdlib/ndarray-base-unary-addon-dispatch' );

function addon( xbuf, metaX, ybuf, metaY ) {
    console.log( xbuf );
    // => <Float64Array>[ 1, 2, 3, 4 ]

    console.log( ybuf );
    // => <Float64Array>[ 0, 0, 0, 0 ]
}

function fallback( x, y ) {
    console.log( ndarray2array( x ) );
    // => [ [ 1, 2 ], [ 3, 4 ] ]

    console.log( ndarray2array( y ) );
    // => [ [ 0, 0 ], [ 0, 0 ] ]
}

// Create a dispatch function:
var f = dispatch( addon, fallback );

// Create ndarrays:
var opts = {
    'dtype': 'float64',
    'casting': 'unsafe'
};
var x = array( [ [ 1, 2 ], [ 3, 4 ] ], opts );
var y = zeros( [ 2, 2 ], opts );

// Dispatch to the add-on function:
f( x, y );

// Define new ndarrays:
opts = {
    'dtype': 'generic'
};
x = array( [ [ 1, 2 ], [ 3, 4 ] ], opts );
y = zeros( [ 2, 2 ], opts );

// Dispatch to the fallback function:
f( x, y );

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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

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License

See LICENSE.

Copyright

Copyright © 2016-2025. The Stdlib Authors.