feat: add ndarray/base/kernels/generic/quaternary/linear

lib/node_modules/@stdlib/ndarray/base/kernels/generic/quaternary/linear/README.md

@@ -0,0 +1,344 @@
+<!--
+
+@license Apache-2.0
+
+Copyright (c) 2026 The Stdlib Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+   http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+
+-->
+
+# kernel
+
+> Return a kernel for applying a quaternary callback to elements in four input ndarrays and assigning results to elements in an output ndarray using linear view iteration.
+
+<section class="intro">
+
+</section>
+
+<!-- /.intro -->
+
+<section class="usage">
+
+## Usage
+
+```javascript
+var kernel = require( '@stdlib/ndarray/base/kernels/generic/quaternary/linear' );
+```
+
+#### kernel( ndims )
+
+Returns a kernel for applying a quaternary callback to elements in four input ndarrays and assigning results to elements in an output ndarray using linear view iteration.
+
+<!-- eslint-disable max-len -->
+
+```javascript
+var Float64Array = require( '@stdlib/array/float64' );
+var ndarray2array = require( '@stdlib/ndarray/base/to-array' );
+var add4 = require( '@stdlib/number/float64/base/add4' );
+
+// Create data buffers:
+var xbuf = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );
+var ybuf = new Float64Array( [ 1.0, 1.0, 1.0, 1.0, 1.0, 1.0 ] );
+var zbuf = new Float64Array( [ 2.0, 2.0, 2.0, 2.0, 2.0, 2.0 ] );
+var wbuf = new Float64Array( [ 3.0, 3.0, 3.0, 3.0, 3.0, 3.0 ] );
+var ubuf = new Float64Array( 6 );
+
+// Define the shape of the input and output arrays:
+var shape = [ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 2 ];
+
+// Define the array strides:
+var sx = [ 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 2, 1 ];
+var sy = [ 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 2, 1 ];
+var sz = [ 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 2, 1 ];
+var sw = [ 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 2, 1 ];
+var su = [ 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 2, 1 ];
+
+// Create the input and output ndarray-like objects:
+var x = {
+    'dtype': 'float64',
+    'data': xbuf,
+    'shape': shape,
+    'strides': sx,
+    'offset': 0,
+    'order': 'row-major'
+};
+var y = {
+    'dtype': 'float64',
+    'data': ybuf,
+    'shape': shape,
+    'strides': sy,
+    'offset': 0,
+    'order': 'row-major'
+};
+var z = {
+    'dtype': 'float64',
+    'data': zbuf,
+    'shape': shape,
+    'strides': sz,
+    'offset': 0,
+    'order': 'row-major'
+};
+var w = {
+    'dtype': 'float64',
+    'data': wbuf,
+    'shape': shape,
+    'strides': sw,
+    'offset': 0,
+    'order': 'row-major'
+};
+var u = {
+    'dtype': 'float64',
+    'data': ubuf,
+    'shape': shape,
+    'strides': su,
+    'offset': 0,
+    'order': 'row-major'
+};
+
+// Resolve a kernel:
+var f = kernel( 13 );
+
+// Apply the quaternary function:
+f( x, y, z, w, u, add4 );
+
+var arr = ndarray2array( u.data, u.shape, u.strides, u.offset, u.order );
+// returns [ [ [ [ [ [ [ [ [ [ [ [ [ 7.0, 8.0 ], [ 9.0, 10.0 ], [ 11.0, 12.0 ] ] ] ] ] ] ] ] ] ] ] ] ]
+```
+
+The function accepts the following arguments:
+
+-   **ndims**: number of dimensions.
+
+If the function is provided an `ndims` value less than `0`, the function returns `null`.
+
+```javascript
+var f = kernel( -1 );
+// returns null
+```
+
+The returned function accepts the following arguments:
+
+-   **x**: first input ndarray descriptor (object with `dtype`, `data`, `shape`, `strides`, `offset`, `order`).
+-   **y**: second input ndarray descriptor.
+-   **z**: third input ndarray descriptor.
+-   **w**: fourth input ndarray descriptor.
+-   **u**: output ndarray descriptor.
+-   **fcn**: quaternary callback accepting four scalar values and returning one scalar value.
+
+The returned function iterates over ndarray elements according to the linear **view** index, regardless as to how the data is stored in memory.
+
+#### kernel.nd( x, y, z, w, u, fcn )
+
+Applies a quaternary callback to elements in n-dimensional input ndarrays and assigns results to elements in an equivalently shaped output ndarray using linear view iteration.
+
+<!-- eslint-disable max-len -->
+
+```javascript
+var Float64Array = require( '@stdlib/array/float64' );
+var ndarray2array = require( '@stdlib/ndarray/base/to-array' );
+var add4 = require( '@stdlib/number/float64/base/add4' );
+
+// Create data buffers:
+var xbuf = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );
+var ybuf = new Float64Array( [ 1.0, 1.0, 1.0, 1.0, 1.0, 1.0 ] );
+var zbuf = new Float64Array( [ 2.0, 2.0, 2.0, 2.0, 2.0, 2.0 ] );
+var wbuf = new Float64Array( [ 3.0, 3.0, 3.0, 3.0, 3.0, 3.0 ] );
+var ubuf = new Float64Array( 6 );
+
+// Define the shape of the input and output arrays:
+var shape = [ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 2 ];
+
+// Define the array strides:
+var sx = [ 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 2, 1 ];
+var sy = [ 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 2, 1 ];
+var sz = [ 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 2, 1 ];
+var sw = [ 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 2, 1 ];
+var su = [ 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 2, 1 ];
+
+// Create the input and output ndarray-like objects:
+var x = {
+    'dtype': 'float64',
+    'data': xbuf,
+    'shape': shape,
+    'strides': sx,
+    'offset': 0,
+    'order': 'row-major'
+};
+var y = {
+    'dtype': 'float64',
+    'data': ybuf,
+    'shape': shape,
+    'strides': sy,
+    'offset': 0,
+    'order': 'row-major'
+};
+var z = {
+    'dtype': 'float64',
+    'data': zbuf,
+    'shape': shape,
+    'strides': sz,
+    'offset': 0,
+    'order': 'row-major'
+};
+var w = {
+    'dtype': 'float64',
+    'data': wbuf,
+    'shape': shape,
+    'strides': sw,
+    'offset': 0,
+    'order': 'row-major'
+};
+var u = {
+    'dtype': 'float64',
+    'data': ubuf,
+    'shape': shape,
+    'strides': su,
+    'offset': 0,
+    'order': 'row-major'
+};
+
+// Apply the quaternary function:
+kernel.nd( x, y, z, w, u, add4 );
+
+var arr = ndarray2array( u.data, u.shape, u.strides, u.offset, u.order );
+// returns [ [ [ [ [ [ [ [ [ [ [ [ [ 7.0, 8.0 ], [ 9.0, 10.0 ], [ 11.0, 12.0 ] ] ] ] ] ] ] ] ] ] ] ] ]
+```
+
+The function has the following parameters:
+
+-   **x**: first input ndarray descriptor (object with `dtype`, `data`, `shape`, `strides`, `offset`, `order`).
+-   **y**: second input ndarray descriptor.
+-   **z**: third input ndarray descriptor.
+-   **w**: fourth input ndarray descriptor.
+-   **u**: output ndarray descriptor.
+-   **fcn**: quaternary callback accepting four scalar values and returning one scalar value.
+
+</section>
+
+<!-- /.usage -->
+
+<section class="notes">
+
+## Notes
+
+-   The quaternary callback is expected to have the following signature:
+
+    ```text
+    fcn( v1, v2, v3, v4 )
+    ```
+
+    where
+
+    -   **v1**: element from the first input ndarray.
+    -   **v2**: element from the second input ndarray.
+    -   **v3**: element from the third input ndarray.
+    -   **v4**: element from the fourth input ndarray.
+
+</section>
+
+<!-- /.notes -->
+
+<section class="examples">
+
+## Examples
+
+<!-- eslint no-undef: "error" -->
+
+<!-- eslint-disable max-len -->
+
+```javascript
+var Float64Array = require( '@stdlib/array/float64' );
+var ndarray2array = require( '@stdlib/ndarray/base/to-array' );
+var add4 = require( '@stdlib/number/float64/base/add4' );
+var kernel = require( '@stdlib/ndarray/base/kernels/generic/quaternary/linear' );
+
+// Create data buffers:
+var xbuf = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );
+var ybuf = new Float64Array( [ 1.0, 1.0, 1.0, 1.0, 1.0, 1.0 ] );
+var zbuf = new Float64Array( [ 2.0, 2.0, 2.0, 2.0, 2.0, 2.0 ] );
+var wbuf = new Float64Array( [ 3.0, 3.0, 3.0, 3.0, 3.0, 3.0 ] );
+var ubuf = new Float64Array( 6 );
+
+// Define the array shapes:
+var shape = [ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 2 ];
+
+// Create the input and output ndarray-like objects:
+var x = {
+    'dtype': 'float64',
+    'data': xbuf,
+    'shape': shape,
+    'strides': [ 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 2, 1 ],
+    'offset': 0,
+    'order': 'row-major'
+};
+var y = {
+    'dtype': 'float64',
+    'data': ybuf,
+    'shape': shape,
+    'strides': [ 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 2, 1 ],
+    'offset': 0,
+    'order': 'row-major'
+};
+var z = {
+    'dtype': 'float64',
+    'data': zbuf,
+    'shape': shape,
+    'strides': [ 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 2, 1 ],
+    'offset': 0,
+    'order': 'row-major'
+};
+var w = {
+    'dtype': 'float64',
+    'data': wbuf,
+    'shape': shape,
+    'strides': [ 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 2, 1 ],
+    'offset': 0,
+    'order': 'row-major'
+};
+var u = {
+    'dtype': 'float64',
+    'data': ubuf,
+    'shape': shape,
+    'strides': [ 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 2, 1 ],
+    'offset': 0,
+    'order': 'row-major'
+};
+
+// Resolve a kernel:
+var f = kernel( 13 );
+
+// Apply the quaternary function:
+f( x, y, z, w, u, add4 );
+
+console.log( ndarray2array( u.data, u.shape, u.strides, u.offset, u.order ) );
+// => [ [ [ [ [ [ [ [ [ [ [ [ [ 7.0, 8.0 ], [ 9.0, 10.0 ], [ 11.0, 12.0 ] ] ] ] ] ] ] ] ] ] ] ] ]
+```
+
+</section>
+
+<!-- /.examples -->
+
+<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->
+
+<section class="related">
+
+</section>
+
+<!-- /.related -->
+
+<section class="links">
+
+</section>
+
+<!-- /.links -->