npm package: @stdlib/blas-gdot
Description: Calculate the dot product of two vectors.
Author: The Stdlib Authors
Latest version: 0.2.3

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# gdot

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

> Calculate the dot product of two vectors.

<section class="intro">

The [dot product][dot-product] (or scalar product) is defined as

<!-- <equation class="equation" label="eq:dot_product" align="center" raw="\mathbf{x}\cdot\mathbf{y} = \sum_{i=0}^{N-1} x_i y_i = x_0 y_0 + x_1 y_1 + \ldots + x_{N-1} y_{N-1}" alt="Dot product definition."> -->

<div class="equation" align="center" data-raw-text="\mathbf{x}\cdot\mathbf{y} = \sum_{i=0}^{N-1} x_i y_i = x_0 y_0 + x_1 y_1 + \ldots + x_{N-1} y_{N-1}" data-equation="eq:dot_product">
    <img src="https://cdn.jsdelivr.net/gh/stdlib-js/stdlib@b7a453f335bade718a3f48a61658d1564dc3f786/lib/node_modules/@stdlib/blas/gdot/docs/img/equation_dot_product.svg" alt="Dot product definition.">
    <br>
</div>

<!-- </equation> -->

</section>

<!-- /.intro -->

<section class="installation">

## Installation

```bash
npm install @stdlib/blas-gdot
```

</section>

<section class="usage">

## Usage

```javascript
var gdot = require( '@stdlib/blas-gdot' );
```

#### gdot( x, y )

Calculates the dot product of vectors `x` and `y`.

```javascript
var Int32Array = require( '@stdlib/array-int32' );
var array = require( '@stdlib/ndarray-array' );

var x = array( new Int32Array( [ 4.0, 2.0, -3.0, 5.0, -1.0 ] ) );
var y = array( new Int32Array( [ 2.0, 6.0, -1.0, -4.0, 8.0 ] ) );

var z = gdot( x, y );
// returns -5.0
```

The function has the following parameters:

-   **x**: a 1-dimensional [`ndarray`][@stdlib/ndarray/array] or an array-like object.
-   **y**: a 1-dimensional [`ndarray`][@stdlib/ndarray/array] or an array-like object.

If provided empty vectors, the function returns `0.0`.

```javascript
var z = gdot( [], [] );
// returns 0.0
```

</section>

<!-- /.usage -->

<section class="notes">

## Notes

-   `gdot()` corresponds to the [BLAS][blas] level 1 function [`ddot`][ddot] with the exception that this implementation works with any array type, not just Float64Arrays.
-   In general, for best performance, especially for large vectors, provide 1-dimensional [`ndarrays`][@stdlib/ndarray/array] whose underlying data type is either `float64` or `float32`.

</section>

<!-- /.notes -->

<section class="examples">

## Examples

<!-- eslint no-undef: "error" -->

```javascript
var discreteUniform = require( '@stdlib/random-base-discrete-uniform' );
var gdot = require( '@stdlib/blas-gdot' );

var rand1 = discreteUniform.factory( 0, 100 );
var rand2 = discreteUniform.factory( 0, 10 );

var x = [];
var y = [];
var i;
for ( i = 0; i < 10; i++ ) {
    x.push( rand1() );
    y.push( rand2() );
}
console.log( x );
console.log( y );

var z = gdot( x, y );
console.log( z );
```

</section>

<!-- /.examples -->

<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->

<section class="related">

* * *

## See Also

-   <span class="package-name">[`@stdlib/blas-base/gdot`][@stdlib/blas/base/gdot]</span><span class="delimiter">: </span><span class="description">calculate the dot product of two vectors.</span>
-   <span class="package-name">[`@stdlib/blas-ddot`][@stdlib/blas/ddot]</span><span class="delimiter">: </span><span class="description">calculate the dot product of two double-precision floating-point vectors.</span>
-   <span class="package-name">[`@stdlib/blas-sdot`][@stdlib/blas/sdot]</span><span class="delimiter">: </span><span class="description">calculate the dot product of two single-precision floating-point vectors.</span>

</section>

<!-- /.related -->

<!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->


<section class="main-repo" >

* * *

## 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 &copy; 2016-2026. The Stdlib [Authors][stdlib-authors].

</section>

<!-- /.stdlib -->

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<section class="links">

[npm-image]: http://img.shields.io/npm/v/@stdlib/blas-gdot.svg
[npm-url]: https://npmjs.org/package/@stdlib/blas-gdot

[test-image]: https://github.com/stdlib-js/blas-gdot/actions/workflows/test.yml/badge.svg?branch=v0.2.3
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[coverage-url]: https://codecov.io/github/stdlib-js/blas-gdot?branch=main

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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/blas-gdot/tree/deno
[deno-readme]: https://github.com/stdlib-js/blas-gdot/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/blas-gdot/tree/umd
[umd-readme]: https://github.com/stdlib-js/blas-gdot/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/blas-gdot/tree/esm
[esm-readme]: https://github.com/stdlib-js/blas-gdot/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/blas-gdot/blob/main/branches.md

[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/blas-gdot/main/LICENSE

[dot-product]: https://en.wikipedia.org/wiki/Dot_product

[blas]: http://www.netlib.org/blas

[ddot]: http://www.netlib.org/lapack/explore-html/df/d28/group__single__blas__level1.html

[@stdlib/ndarray/array]: https://www.npmjs.com/package/@stdlib/ndarray-array

<!-- <related-links> -->

[@stdlib/blas/base/gdot]: https://www.npmjs.com/package/@stdlib/blas-base-gdot

[@stdlib/blas/ddot]: https://www.npmjs.com/package/@stdlib/blas-ddot

[@stdlib/blas/sdot]: https://www.npmjs.com/package/@stdlib/blas-sdot

<!-- </related-links> -->

</section>

<!-- /.links -->