Usage

`javascript
var dnrm2 = require( '@stdlib/blas-base-dnrm2' );
`

#### dnrm2( N, x, stride )

Computes the [L2-norm][l2-norm] of a double-precision floating-point vector x.

`javascript
var Float64Array = require( '@stdlib/array-float64' );

var x = new Float64Array( [ 1.0, -2.0, 2.0 ] );

var z = dnrm2( 3, x, 1 );
// returns 3.0
`

The function has the following parameters:

- N: number of indexed elements.
- x: input [Float64Array][@stdlib/array/float64].
- stride: index increment for x.

The N and stride parameters determine which elements in x are accessed at runtime. For example, to compute the [L2-norm][l2-norm] of every other element in x,

`javascript
var Float64Array = require( '@stdlib/array-float64' );

var x = new Float64Array( [ 1.0, 2.0, 2.0, -7.0, -2.0, 3.0, 4.0, 2.0 ] );

var z = dnrm2( 4, x, 2 );
// returns 5.0
`

Note that indexing is relative to the first index. To introduce an offset, use [typed array][mdn-typed-array] views.

`javascript
var Float64Array = require( '@stdlib/array-float64' );

var x0 = new Float64Array( [ 2.0, 1.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0 ] );
var x1 = new Float64Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element

var z = dnrm2( 4, x1, 2 );
// returns 5.0
`

If N is less than or equal to 0, the function returns 0.

#### dnrm2.ndarray( N, x, stride, offset )

Computes the [L2-norm][l2-norm] of a double-precision floating-point vector using alternative indexing semantics.

`javascript
var Float64Array = require( '@stdlib/array-float64' );

var x = new Float64Array( [ 1.0, -2.0, 2.0 ] );

var z = dnrm2.ndarray( 3, x, 1, 0 );
// returns 3.0
`

The function has the following additional parameters:

- offset: starting index for x.

While [typed array][mdn-typed-array] views mandate a view offset based on the underlying buffer, the offset parameter supports indexing semantics based on a starting index. For example, to calculate the [L2-norm][l2-norm] for every other value in x starting from the second value

`javascript
var Float64Array = require( '@stdlib/array-float64' );

var x = new Float64Array( [ 2.0, 1.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0 ] );

var z = dnrm2.ndarray( 4, x, 2, 1 );
// returns 5.0
`