npm package: @stdlib/blas-base-ndarray-ddot
Description: Compute the dot product of two one-dimensional double-precision floating-point ndarrays.
Author: The Stdlib Authors
Latest version: 0.1.1

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  <p>We believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js.</p>
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# ddot

[![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 one-dimensional double-precision floating-point ndarrays.

<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@6cf4829ce9c06ba9fa207a2ea3b395266f86a259/lib/node_modules/@stdlib/blas/base/ndarray/ddot/docs/img/equation_dot_product.svg" alt="Dot product definition.">
    <br>
</div>

<!-- </equation> -->

</section>

<!-- /.intro -->

<section class="installation">

## Installation

```bash
npm install @stdlib/blas-base-ndarray-ddot
```

</section>

<section class="usage">

## Usage

```javascript
var ddot = require( '@stdlib/blas-base-ndarray-ddot' );
```

#### ddot( arrays )

Computes the dot product of two one-dimensional double-precision floating-point ndarrays.

```javascript
var Float64Array = require( '@stdlib/array-float64' );
var ndarray = require( '@stdlib/ndarray-base-ctor' );

var xbuf = new Float64Array( [ 4.0, 2.0, -3.0, 5.0, -1.0 ] );
var x = new ndarray( 'float64', xbuf, [ 5 ], [ 1 ], 0, 'row-major' );

var ybuf = new Float64Array( [ 2.0, 6.0, -1.0, -4.0, 8.0 ] );
var y = new ndarray( 'float64', ybuf, [ 5 ], [ 1 ], 0, 'row-major' );

var z = ddot( [ x, y ] );
// returns -5.0
```

The function has the following parameters:

-   **arrays**: array-like object containing two one-dimensional input ndarrays.

</section>

<!-- /.usage -->

<section class="notes">

</section>

<!-- /.notes -->

<section class="examples">

## Examples

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

```javascript
var discreteUniform = require( '@stdlib/random-array-discrete-uniform' );
var ndarray = require( '@stdlib/ndarray-base-ctor' );
var ndarray2array = require( '@stdlib/ndarray-to-array' );
var ddot = require( '@stdlib/blas-base-ndarray-ddot' );

var opts = {
    'dtype': 'float64'
};

var xbuf = discreteUniform( 10, 0, 500, opts );
var x = new ndarray( opts.dtype, xbuf, [ xbuf.length ], [ 1 ], 0, 'row-major' );
console.log( ndarray2array( x ) );

var ybuf = discreteUniform( 10, 0, 255, opts );
var y = new ndarray( opts.dtype, ybuf, [ ybuf.length ], [ 1 ], 0, 'row-major' );
console.log( ndarray2array( y ) );

var out = ddot( [ x, y ] );
console.log( out );
```

</section>

<!-- /.examples -->

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

<section class="related">

</section>

<!-- /.related -->

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<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].

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

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

</section>

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