Usage

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

#### csum( N, x, strideX )

Computes the sum of single-precision complex floating-point strided array elements.

`javascript
var Complex64Array = require( '@stdlib/array-complex64' );

var x = new Complex64Array( [ 1.0, -2.0, 2.0, 3.0 ] );

var v = csum( x.length, x, 1 );
// returns [ 3.0, 1.0 ]
`

The function has the following parameters:

- N: number of indexed elements.
- x: input [Complex64Array][@stdlib/array/complex64].
- strideX: stride length for x.

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

`javascript
var Complex64Array = require( '@stdlib/array-complex64' );

var x = new Complex64Array( [ 1.0, 2.0, 2.0, -7.0, -2.0, 3.0, 4.0, 2.0 ] );

var v = csum( 2, x, 2 );
// returns [ -1.0, 5.0 ]
`

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

`javascript
var Complex64Array = require( '@stdlib/array-complex64' );

var x0 = new Complex64Array( [ 2.0, 1.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0 ] );
var x1 = new Complex64Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element

var v = csum( 2, x1, 2 );
// returns [ 5.0, 2.0 ]
`

#### csum.ndarray( N, x, strideX, offsetX )

Computes the sum of single-precision complex floating-point strided array elements using alternative indexing semantics.

`javascript
var Complex64Array = require( '@stdlib/array-complex64' );

var x = new Complex64Array( [ 1.0, -2.0, 2.0, 3.0 ] );

var v = csum.ndarray( 2, x, 1, 0 );
// returns [ 3.0, 1.0 ]
`

The function has the following additional parameters:

- offsetX: 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 sum of every other element starting from the second element:

`javascript
var Complex64Array = require( '@stdlib/array-complex64' );

var x = new Complex64Array( [ 2.0, 1.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0 ] );

var v = csum.ndarray( 2, x, 2, 1 );
// returns [ 5.0, 2.0 ]
`