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About stdlib...

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.

The library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases.

When you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, well-written, studied, documented, tested, measured, and high-quality code out there.

To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!

gdot

NPM version Build Status Coverage Status

Calculate the dot product of two vectors.

The dot product (or scalar product) is defined as

$$\mathbf{x}\cdot\mathbf{y} = \sum_{i=0}^{N-1} x_i y_i = x_0 y_0 + x_1 y_1 + \ldots + x_{N-1} y_{N-1}$$

Installation

npm install @stdlib/blas-gdot

Alternatively,

  • To load the package in a website via a script tag without installation and bundlers, use the ES Module available on the esm branch (see README).
  • If you are using Deno, visit the deno branch (see README for usage intructions).
  • For use in Observable, or in browser/node environments, use the Universal Module Definition (UMD) build available on the umd branch (see README).

The branches.md 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

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

gdot( x, y )

Calculates the dot product of vectors x and y.

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 or an array-like object.
  • y: a 1-dimensional ndarray or an array-like object.

If provided empty vectors, the function returns 0.0.

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

Notes

  • gdot() corresponds to the BLAS level 1 function 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 whose underlying data type is either float64 or float32.

Examples

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 );

See Also

Notice

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

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License

See LICENSE.

Copyright

Copyright © 2016-2024. The Stdlib Authors.