@stdlib/blas-gdot NPM

gdot

Calculate the dot product of two vectors.

The dot product (or scalar product) is defined as

Installation

npm install @stdlib/blas-gdot

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 );

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.