gdot

gdot

Calculate the dot product of two vectors.

The dot product (or scalar product) is defined as

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.
• For best performance, 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 );