https://github.com/stdlib-js/ndarray-base-unary-reduce-strided1d-assign-struct

Perform a reduction over a list of specified dimensions in an input ndarray via a one-dimensional strided array reduction function and assign results to a provided output ndarray.
https://github.com/stdlib-js/ndarray-base-unary-reduce-strided1d-assign-struct

accumulate accumulation array base javascript ndarray node node-js nodejs reduce reduction stdlib strided struct unary vector

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Perform a reduction over a list of specified dimensions in an input ndarray via a one-dimensional strided array reduction function and assign results to a provided output ndarray.

Host: GitHub
URL: https://github.com/stdlib-js/ndarray-base-unary-reduce-strided1d-assign-struct
Owner: stdlib-js
License: apache-2.0
Created: 2025-06-24T08:29:40.000Z (4 months ago)
Default Branch: main
Last Pushed: 2025-08-15T12:56:32.000Z (about 2 months ago)
Last Synced: 2025-08-15T14:53:59.388Z (about 2 months ago)
Topics: accumulate, accumulation, array, base, javascript, ndarray, node, node-js, nodejs, reduce, reduction, stdlib, strided, struct, unary, vector
Language: JavaScript
Homepage: https://github.com/stdlib-js/stdlib
Size: 1.9 MB
Stars: 0
Watchers: 0
Forks: 0
Open Issues: 0
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
- Code of conduct: CODE_OF_CONDUCT.md
- Citation: CITATION.cff
- Security: SECURITY.md

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# unaryReduceStrided1d

[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url] 

> Perform a reduction over a list of specified dimensions in an input ndarray via a one-dimensional strided array reduction function which accepts an output [`struct`][@stdlib/dstructs/struct] object and assign results to a provided output ndarray.

## Installation

```bash

npm install @stdlib/ndarray-base-unary-reduce-strided1d-assign-struct

```

Alternatively,

-   To load the package in a website via a `script` tag without installation and bundlers, use the [ES Module][es-module] available on the [`esm`][esm-url] branch (see [README][esm-readme]).

-   If you are using Deno, visit the [`deno`][deno-url] branch (see [README][deno-readme] for usage intructions).

-   For use in Observable, or in browser/node environments, use the [Universal Module Definition (UMD)][umd] build available on the [`umd`][umd-url] branch (see [README][umd-readme]).

The [branches.md][branches-url] 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

```javascript

var unaryReduceStrided1d = require( '@stdlib/ndarray-base-unary-reduce-strided1d-assign-struct' );

```

#### unaryReduceStrided1d( fcn, arrays, dims\[, options] )

Performs a reduction over a list of specified dimensions in an input ndarray via a one-dimensional strided array reduction function which accepts an output [`struct`][@stdlib/dstructs/struct] object and assigns results to a provided output ndarray.

```javascript

var Float64Array = require( '@stdlib/array-float64' );

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

var Float64Results = require( '@stdlib/stats-base-ztest-one-sample-results-float64' );

var structFactory = require( '@stdlib/array-struct-factory' );

var ztest = require( '@stdlib/stats-base-ndarray-ztest' );

var ResultsArray = structFactory( Float64Results );

// Create data buffers:

var xbuf = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, 12.0 ] );

var ybuf = new ResultsArray( 3 );

// Define the array shapes:

var xsh = [ 1, 3, 2, 2 ];

var ysh = [ 1, 3 ];

// Define the array strides:

var sx = [ 12, 4, 2, 1 ];

var sy = [ 3, 1 ];

// Define the index offsets:

var ox = 0;

var oy = 0;

// Create an input ndarray-like object:

var x = {

    'dtype': 'float64',

    'data': xbuf,

    'shape': xsh,

    'strides': sx,

    'offset': ox,

    'order': 'row-major'

};

// Create an output ndarray-like object:

var y = {

    'dtype': Float64Results,

    'data': ybuf,

    'shape': ysh,

    'strides': sy,

    'offset': oy,

    'order': 'row-major'

};

// Create additional parameter ndarray-like objects:

var alternative = {

    'dtype': 'generic',

    'data': [ 'two-sided' ],

    'shape': ysh,

    'strides': [ 0, 0 ],

    'offset': 0,

    'order': 'row-major'

};

var alpha = {

    'dtype': 'float64',

    'data': [ 0.05 ],

    'shape': ysh,

    'strides': [ 0, 0 ],

    'offset': 0,

    'order': 'row-major'

};

var mu = {

    'dtype': 'float64',

    'data': [ 0.0 ],

    'shape': ysh,

    'strides': [ 0, 0 ],

    'offset': 0,

    'order': 'row-major'

};

var sigma = {

    'dtype': 'float64',

    'data': [ 1.0 ],

    'shape': ysh,

    'strides': [ 0, 0 ],

    'offset': 0,

    'order': 'row-major'

};

// Perform a reduction:

unaryReduceStrided1d( ztest, [ x, y, alternative, alpha, mu, sigma ], [ 2, 3 ] );

var arr = ndarray2array( y.data, y.shape, y.strides, y.offset, y.order );

// returns [ [ , ,  ] ]

```

The function accepts the following arguments:

-   **fcn**: function which will be applied to a one-dimensional subarray and should store reduction results in an output [`struct`][@stdlib/dstructs/struct] object.

-   **arrays**: array-like object containing one input ndarray and one output ndarray, followed by any additional ndarray arguments.

-   **dims**: list of dimensions over which to perform a reduction.

-   **options**: function options which are passed through to `fcn` (_optional_).

Each provided ndarray should be an object with the following properties:

-   **dtype**: data type.

-   **data**: data buffer.

-   **shape**: dimensions.

-   **strides**: stride lengths.

-   **offset**: index offset.

-   **order**: specifies whether an ndarray is row-major (C-style) or column major (Fortran-style).

#### TODO: document factory method

## Notes

-   The output ndarray and any additional ndarray arguments are expected to have the same dimensions as the non-reduced dimensions of the input ndarray. When calling the reduction function, any additional ndarray arguments are provided as zero-dimensional ndarray-like objects.

-   The reduction function is expected to have the following signature:

    ```text

    fcn( arrays[, options] )

    ```

    where

    -   **arrays**: array containing a one-dimensional subarray of the input ndarray, a zero-dimensional subarray of the output ndarray containing the output [`struct`][@stdlib/dstructs/struct] object, and any additional ndarray arguments as zero-dimensional ndarrays.

    -   **options**: function options (_optional_).

-   For very high-dimensional ndarrays which are non-contiguous, one should consider copying the underlying data to contiguous memory before performing a reduction in order to achieve better performance.

## Examples

```javascript

var normal = require( '@stdlib/random-array-normal' );

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

var Float64Results = require( '@stdlib/stats-base-ztest-one-sample-results-float64' );

var structFactory = require( '@stdlib/array-struct-factory' );

var ztest = require( '@stdlib/stats-base-ndarray-ztest' );

var unaryReduceStrided1d = require( '@stdlib/ndarray-base-unary-reduce-strided1d-assign-struct' );

var ResultsArray = structFactory( Float64Results );

var N = 10;

var x = {

    'dtype': 'generic',

    'data': normal( N, 0.0, 1.0, {

        'dtype': 'generic'

    }),

    'shape': [ 1, 5, 2 ],

    'strides': [ 10, 2, 1 ],

    'offset': 0,

    'order': 'row-major'

};

var y = {

    'dtype': Float64Results,

    'data': new ResultsArray( 2 ),

    'shape': [ 1, 2 ],

    'strides': [ 2, 1 ],

    'offset': 0,

    'order': 'row-major'

};

var alternative = {

    'dtype': 'generic',

    'data': [ 'two-sided' ],

    'shape': [ 1, 2 ],

    'strides': [ 0, 0 ],

    'offset': 0,

    'order': 'row-major'

};

var alpha = {

    'dtype': 'generic',

    'data': [ 0.05 ],

    'shape': [ 1, 2 ],

    'strides': [ 0, 0 ],

    'offset': 0,

    'order': 'row-major'

};

var mu = {

    'dtype': 'generic',

    'data': [ 0.0 ],

    'shape': [ 1, 2 ],

    'strides': [ 0, 0 ],

    'offset': 0,

    'order': 'row-major'

};

var sigma = {

    'dtype': 'generic',

    'data': [ 1.0 ],

    'shape': [ 1, 2 ],

    'strides': [ 0, 0 ],

    'offset': 0,

    'order': 'row-major'

};

unaryReduceStrided1d( ztest, [ x, y, alternative, alpha, mu, sigma ], [ 1 ] );

console.log( ndarray2array( x.data, x.shape, x.strides, x.offset, x.order ) );

console.log( ndarray2array( y.data, y.shape, y.strides, y.offset, y.order ) );

```

* * *

## Notice

This package is part of [stdlib][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][stdlib], see the main project [repository][stdlib].

#### Community

[![Chat][chat-image]][chat-url]

---

## License

See [LICENSE][stdlib-license].

## Copyright

Copyright © 2016-2025. The Stdlib [Authors][stdlib-authors].

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[stdlib]: https://github.com/stdlib-js/stdlib

[stdlib-authors]: https://github.com/stdlib-js/stdlib/graphs/contributors

[umd]: https://github.com/umdjs/umd

[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules

[deno-url]: https://github.com/stdlib-js/ndarray-base-unary-reduce-strided1d-assign-struct/tree/deno

[deno-readme]: https://github.com/stdlib-js/ndarray-base-unary-reduce-strided1d-assign-struct/blob/deno/README.md

[umd-url]: https://github.com/stdlib-js/ndarray-base-unary-reduce-strided1d-assign-struct/tree/umd

[umd-readme]: https://github.com/stdlib-js/ndarray-base-unary-reduce-strided1d-assign-struct/blob/umd/README.md

[esm-url]: https://github.com/stdlib-js/ndarray-base-unary-reduce-strided1d-assign-struct/tree/esm

[esm-readme]: https://github.com/stdlib-js/ndarray-base-unary-reduce-strided1d-assign-struct/blob/esm/README.md

[branches-url]: https://github.com/stdlib-js/ndarray-base-unary-reduce-strided1d-assign-struct/blob/main/branches.md

[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/ndarray-base-unary-reduce-strided1d-assign-struct/main/LICENSE

[@stdlib/dstructs/struct]: https://github.com/stdlib-js/dstructs-struct

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