# gdot
> Calculate the dot product of two vectors.
The [dot product][dot-product] (or scalar product) is defined as
## Usage
```javascript
var gdot = require( '@stdlib/blas/gdot' );
```
#### gdot( x, y )
Calculates the dot product of vectors `x` and `y`.
```javascript
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`][@stdlib/ndarray/array] or an array-like object.
- **y**: a 1-dimensional [`ndarray`][@stdlib/ndarray/array] or an array-like object.
If provided empty vectors, the function returns `0.0`.
```javascript
var z = gdot( [], [] );
// returns 0.0
```
## Notes
- `gdot()` corresponds to the [BLAS][blas] level 1 function [`ddot`][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`][@stdlib/ndarray/array] whose underlying data type is either `float64` or `float32`.
## Examples
```javascript
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 );
```
[dot-product]: https://en.wikipedia.org/wiki/Dot_product
[blas]: http://www.netlib.org/blas
[ddot]: http://www.netlib.org/lapack/explore-html/df/d28/group__single__blas__level1.html
[@stdlib/ndarray/array]: https://www.npmjs.com/package/@stdlib/ndarray-array
