@stdlib/strided
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Strided.
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# dispatch
> Dispatch to a native add-on applying a binary function to two input strided arrays.
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</section>
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<section class="usage">
## Usage
```javascript
var dispatch = require( '@stdlib/strided/base/binary-addon-dispatch' );
```
#### dispatch( addon, fallback )
Returns a function which dispatches to a native add-on applying a binary function to two input strided arrays.
<!-- eslint-disable max-len -->
```javascript
function addon( N, dtypeX, x, strideX, dtypeY, y, strideY, dtypeZ, z, strideZ ) {
// Call into native add-on...
}
function fallback( N, dtypeX, x, strideX, dtypeY, y, strideY, dtypeZ, z, strideZ ) {
// Fallback JavaScript implementation...
}
// Create a dispatch function:
var f = dispatch( addon, fallback );
// ...
// Invoke the dispatch function with strided array arguments:
f( 2, 'generic', [ 1, 2 ], 1, 'generic', [ 3, 4 ], 1, 'generic', [ 0, 0 ], 1 );
```
The returned function has the following signature:
```text
f( N, dtypeX, x, strideX, dtypeY, y, strideY, dtypeZ, z, strideZ )
```
where
- **N**: number of indexed elements.
- **dtypeX**: `x` data type.
- **x**: input array.
- **strideX**: `x` stride length.
- **dtypeY**: `y` data type.
- **y**: input array.
- **strideY**: `y` stride length.
- **dtypeZ**: `z` data type.
- **z**: output array.
- **strideZ**: `z` stride length.
The `addon` function should have the following signature:
```text
f( N, dtypeX, x, strideX, dtypeY, y, strideY, dtypeZ, z, strideZ )
```
where
- **N**: number of indexed elements.
- **dtypeX**: `x` data type (enumeration constant).
- **x**: input array.
- **strideX**: `x` stride length.
- **dtypeY**: `y` data type (enumeration constant).
- **y**: input array.
- **strideY**: `y` stride length.
- **dtypeZ**: `z` data type (enumeration constant).
- **z**: output array.
- **strideZ**: `z` stride length.
The `fallback` function should have the following signature:
```text
f( N, dtypeX, x, strideX, dtypeY, y, strideY, dtypeZ, z, strideZ )
```
where
- **N**: number of indexed elements.
- **dtypeX**: `x` data type.
- **x**: input array.
- **strideX**: `x` stride length.
- **dtypeY**: `y` data type.
- **y**: input array.
- **strideY**: `y` stride length.
- **dtypeZ**: `z` data type.
- **z**: output array.
- **strideZ**: `z` stride length.
#### dispatch.ndarray( addon, fallback )
Returns a function which dispatches to a native add-on applying a binary function to two input strided arrays using alternative indexing semantics.
<!-- eslint-disable max-len, max-params -->
```javascript
function addon( N, dtypeX, x, strideX, dtypeY, y, strideY, dtypeZ, z, strideZ ) {
// Call into native add-on...
}
function fallback( N, dtypeX, x, strideX, offsetX, dtypeY, y, strideY, offsetY, dtypeZ, z, strideZ, offsetZ ) {
// Fallback JavaScript implementation...
}
// Create a dispatch function:
var f = dispatch.ndarray( addon, fallback );
// ...
// Invoke the dispatch function with strided array arguments:
f( 2, 'generic', [ 1, 2 ], 1, 0, 'generic', [ 3, 4 ], 1, 0, 'generic', [ 0, 0 ], 1, 0 );
```
The returned function has the following signature:
```text
f( N, dtypeX, x, strideX, offsetX, dtypeY, y, strideY, offsetY, dtypeZ, z, strideZ, offsetZ )
```
where
- **N**: number of indexed elements.
- **dtypeX**: `x` data type.
- **x**: input array.
- **strideX**: `x` stride length.
- **offsetX**: starting `x` index.
- **dtypeY**: `y` data type.
- **y**: input array.
- **strideY**: `y` stride length.
- **offsetY**: starting `y` index.
- **dtypeZ**: `z` data type.
- **z**: output array.
- **strideZ**: `z` stride length.
- **offsetZ**: starting `z` index.
The `addon` function should have the following signature:
```text
f( N, dtypeX, x, strideX, dtypeY, y, strideY, dtypeZ, z, strideZ )
```
where
- **N**: number of indexed elements.
- **dtypeX**: `x` data type (enumeration constant).
- **x**: input array.
- **strideX**: `x` stride length.
- **dtypeY**: `y` data type (enumeration constant).
- **y**: input array.
- **strideY**: `y` stride length.
- **dtypeZ**: `z` data type (enumeration constant).
- **z**: output array.
- **strideZ**: `z` stride length.
The `fallback` function should have the following signature:
```text
f( N, dtypeX, x, strideX, offsetX, dtypeY, y, strideY, offsetY, dtypeZ, z, strideZ, offsetZ )
```
where
- **N**: number of indexed elements.
- **dtypeX**: `x` data type.
- **x**: input array.
- **strideX**: `x` stride length.
- **offsetX**: starting `x` index.
- **dtypeY**: `y` data type.
- **y**: input array.
- **strideY**: `y` stride length.
- **offsetY**: starting `y` index.
- **dtypeZ**: `z` data type.
- **z**: output array.
- **strideZ**: `z` stride length.
- **offsetZ**: starting `z` index.
</section>
<!-- /.usage -->
<!-- Package usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
<section class="notes">
## Notes
- To determine whether to dispatch to the `addon` function, the returned dispatch function checks whether the provided arrays are typed arrays. If the provided arrays are typed arrays, the dispatch function invokes the `addon` function; otherwise, the dispatch function invokes the `fallback` function.
</section>
<!-- /.notes -->
<!-- Package usage examples. -->
<section class="examples">
## Examples
<!-- eslint-disable max-len, max-params -->
<!-- eslint no-undef: "error" -->
```javascript
var Float64Array = require( '@stdlib/array/float64' );
var dispatch = require( '@stdlib/strided/base/binary-addon-dispatch' );
function addon( N, dtypeX, x, strideX, dtypeY, y, strideY, dtypeZ, z, strideZ ) {
console.log( x );
// => <Float64Array>[ 3, 4 ]
console.log( y );
// => <Float64Array>[ 7, 8 ]
console.log( z );
// => <Float64Array>[ 0, 0 ]
}
function fallback( N, dtypeX, x, strideX, offsetX, dtypeY, y, strideY, offsetY, dtypeZ, z, strideZ, offsetZ ) {
console.log( x );
// => [ 1, 2, 3, 4 ]
console.log( y );
// => [ 5, 6, 7, 8 ]
console.log( z );
// => [ 0, 0, 0, 0 ]
}
// Create a dispatch function:
var f = dispatch.ndarray( addon, fallback );
// Create strided arrays:
var x = new Float64Array( [ 1, 2, 3, 4 ] );
var y = new Float64Array( [ 5, 6, 7, 8 ] );
var z = new Float64Array( [ 0, 0, 0, 0 ] );
// Dispatch to the add-on function:
f( 2, 'float64', x, 1, 2, 'float64', y, 1, 2, 'float64', z, 1, 2 );
// Define new strided arrays:
x = [ 1, 2, 3, 4 ];
y = [ 5, 6, 7, 8 ];
z = [ 0, 0, 0, 0 ];
// Dispatch to the fallback function:
f( 2, 'generic', x, 1, 2, 'generic', y, 1, 2, 'generic', z, 1, 2 );
```
</section>
<!-- /.examples -->
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