Usage

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

#### dapx( N, alpha, x, strideX )

Adds a scalar constant to each element in a double-precision floating-point strided array.

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

var x = new Float64Array( [ -2.0, 1.0, 3.0, -5.0, 4.0, 0.0, -1.0, -3.0 ] );

dapx( x.length, 5.0, x, 1 );
// x => [ 3.0, 6.0, 8.0, 0.0, 9.0, 5.0, 4.0, 2.0 ]
`

The function has the following parameters:

- N: number of indexed elements.
- alpha: scalar constant.
- x: input [Float64Array][@stdlib/array/float64].
- strideX: stride length.

The N and stride parameters determine which elements in the strided array are accessed at runtime. For example, to add a constant to every other element:

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

var x = new Float64Array( [ -2.0, 1.0, 3.0, -5.0, 4.0, 0.0, -1.0, -3.0 ] );

dapx( 4, 5.0, x, 2 );
// x => [ 3.0, 1.0, 8.0, -5.0, 9.0, 0.0, 4.0, -3.0 ]
`

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' );

// Initial array...
var x0 = new Float64Array( [ 1.0, -2.0, 3.0, -4.0, 5.0, -6.0 ] );

// Create an offset view...
var x1 = new Float64Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element

// Add a constant to every other element...
dapx( 3, 5.0, x1, 2 );
// x0 => [ 1.0, 3.0, 3.0, 1.0, 5.0, -1.0 ]
`

#### dapx.ndarray( N, alpha, x, strideX, offsetX )

Adds a scalar constant to each element in a double-precision floating-point strided array using alternative indexing semantics.

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

var x = new Float64Array( [ -2.0, 1.0, 3.0, -5.0, 4.0, 0.0, -1.0, -3.0 ] );

dapx.ndarray( x.length, 5.0, x, 1, 0 );
// x => [ 3.0, 6.0, 8.0, 0.0, 9.0, 5.0, 4.0, 2.0 ]
`

The function has the following additional parameters:

- offsetX: starting index.

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 access only the last three elements:

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

var x = new Float64Array( [ 1.0, -2.0, 3.0, -4.0, 5.0, -6.0 ] );

dapx.ndarray( 3, 5.0, x, 1, x.length-3 );
// x => [ 1.0, -2.0, 3.0, 1.0, 10.0, -1.0 ]
`