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README.md

ddot

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

The dot product (or scalar product) is defined as

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

Usage

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

ddot( arrays )

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

var Float64Vector = require( '@stdlib/ndarray/vector/float64' );

var x = new Float64Vector( [ 4.0, 2.0, -3.0, 5.0, -1.0 ] );
var y = new Float64Vector( [ 2.0, 6.0, -1.0, -4.0, 8.0 ] );

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

The function has the following parameters:

  • arrays: array-like object containing the following ndarrays:

    • first one-dimensional input ndarray.
    • second one-dimensional input ndarray.

Examples

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

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

var x = discreteUniform( [ 10 ], 0, 500, opts );
console.log( ndarray2array( x ) );

var y = discreteUniform( [ 10 ], 0, 255, opts );
console.log( ndarray2array( y ) );

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