Usage

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

#### sasum( N, x, stride )

Computes the sum of [absolute values][@stdlib/math/base/special/abs].

`javascript
var Float32Array = require( '@stdlib/array-float32' );

var x = new Float32Array( [ -2.0, 1.0, 3.0, -5.0, 4.0, 0.0, -1.0, -3.0 ] );

var sum = sasum( x.length, x, 1 );
// returns 19.0
`

The function has the following parameters:

- N: number of indexed elements.
- x: input [Float32Array][mdn-float32array].
- stride: index increment.

The N and stride parameters determine which elements in x are used to compute the sum. For example, to sum every other value,

`javascript
var Float32Array = require( '@stdlib/array-float32' );

var x = new Float32Array( [ -2.0, 1.0, 3.0, -5.0, 4.0, 0.0, -1.0, -3.0 ] );

var sum = sasum( 4, x, 2 );
// returns 10.0
`

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

`javascript
var Float32Array = require( '@stdlib/array-float32' );

// Initial array:
var x0 = new Float32Array( [ 1.0, -2.0, 3.0, -4.0, 5.0, -6.0 ] );

// Create an offset view:
var x1 = new Float32Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element

// Sum every other value:
var sum = sasum( 3, x1, 2 );
// returns 12.0
`

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

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

Computes the sum of [absolute values][@stdlib/math/base/special/abs] using alternative indexing semantics.

`javascript
var Float32Array = require( '@stdlib/array-float32' );

var x = new Float32Array( [ -2.0, 1.0, 3.0, -5.0, 4.0, 0.0, -1.0, -3.0 ] );

var sum = sasum.ndarray( x.length, x, 1, 0 );
// returns 19.0
`

The function has the following additional parameters:

- offset: 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 sum the last three elements,

`javascript
var Float32Array = require( '@stdlib/array-float32' );

var x = new Float32Array( [ 1.0, -2.0, 3.0, -4.0, 5.0, -6.0 ] );

var sum = sasum.ndarray( 3, x, 1, x.length-3 );
// returns 15.0

// Using a negative stride to sum from the last element:
sum = sasum.ndarray( 3, x, -1, x.length-1 );
// returns 15.0
`