Usage

`javascript
var dcityblock = require( '@stdlib/stats-strided-distances-dcityblock' );
`

#### dcityblock( N, x, strideX, y, strideY )

Computes the city block (Manhattan) distance between two double-precision floating-point strided arrays.

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

var x = new Float64Array( [ 4.0, 2.0, -3.0, 5.0, -1.0 ] );
var y = new Float64Array( [ 2.0, 6.0, -1.0, -4.0, 8.0 ] );

var z = dcityblock( x.length, x, 1, y, 1 );
// returns 26.0
`

The function has the following parameters:

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

The N and stride parameters determine which elements in the strided arrays are accessed at runtime. For example, to calculate the city block (Manhattan) distance between every other element in x and the first N elements of y in reverse order,

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

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

var z = dcityblock( 3, x, 2, y, -1 );
// returns 6.0
`

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 arrays...
var x0 = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );
var y0 = new Float64Array( [ 7.0, 8.0, 9.0, 10.0, 11.0, 12.0 ] );

// Create offset views...
var x1 = new Float64Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
var y1 = new Float64Array( y0.buffer, y0.BYTES_PER_ELEMENT*3 ); // start at 4th element

var z = dcityblock( 3, x1, 1, y1, 1 );
// returns 24.0
`

#### dcityblock.ndarray( N, x, strideX, offsetX, y, strideY, offsetY )

Computes the city block (Manhattan) distance between two double-precision floating-point strided arrays using alternative indexing semantics.

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

var x = new Float64Array( [ 4.0, 2.0, -3.0, 5.0, -1.0 ] );
var y = new Float64Array( [ 2.0, 6.0, -1.0, -4.0, 8.0 ] );

var z = dcityblock.ndarray( x.length, x, 1, 0, y, 1, 0 );
// returns 26.0
`

The function has the following additional parameters:

- offsetX: starting index for x.
- offsetY: starting index for y.

While [typed array][mdn-typed-array] views mandate a view offset based on the underlying buffer, the offset parameters support indexing semantics based on starting indices. For example, to calculate the city block (Manhattan) distance between every other element in x starting from the second element with the last 3 elements in y in reverse order

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

var x = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );
var y = new Float64Array( [ 7.0, 8.0, 9.0, 10.0, 11.0, 12.0 ] );

var z = dcityblock.ndarray( 3, x, 2, 1, y, -1, y.length-1 );
// returns 21.0
`