Usage

`javascript
var acotBy = require( '@stdlib/math-strided-special-acot-by' );
`

#### acotBy( N, x, strideX, y, strideY, clbk\[, thisArg] )

Computes the [inverse cotangent][@stdlib/math/base/special/acot] of each element retrieved from an input strided array x via a callback function and assigns each result to an element in an output strided array y.

`javascript
function accessor( v ) {
return v;
}

var x = [ -2.5, -1.5, -0.5, 0.0, 0.5 ];
var y = [ 0.0, 0.0, 0.0, 0.0, 0.0 ];

acotBy( x.length, x, 1, y, 1, accessor );
// y => [ ~-0.381, ~-0.588, ~-1.107, ~1.571, ~1.107 ]
`

The function accepts the following arguments:

- N: number of indexed elements.
- x: input [Array][mdn-array], [typed array][mdn-typed-array], or an array-like object (excluding strings and functions).
- strideX: index increment for x.
- y: output [Array][mdn-array], [typed array][mdn-typed-array], or an array-like object (excluding strings and functions).
- strideY: index increment for y.
- clbk: callback function.
- thisArg: execution context (_optional_).

The invoked callback function is provided six arguments:

- value: input array element.
- idx: iteration index (zero-based).
- xi: input array strided index (offsetX + idx*strideX).
- yi: output array strided index (offsetY + idx*strideY).
- x: input array/collection.
- y: output array/collection.

To set the callback execution context, provide a thisArg.

`javascript
function accessor( v ) {
this.count += 1;
return v;
}

var context = {
'count': 0
};

var x = [ -2.5, -1.5, -0.5, 0.0, 0.5 ];
var y = [ 0.0, 0.0, 0.0, 0.0, 0.0 ];

acotBy( x.length, x, 1, y, 1, accessor, context );
// y => [ ~-0.381, ~-0.588, ~-1.107, ~1.571, ~1.107 ]

var cnt = context.count;
// returns 5
`

The N and stride parameters determine which elements in x and y are accessed at runtime. For example, to index every other value in x and to index the first N elements of y in reverse order,

`javascript
function accessor( v ) {
return v;
}

var x = [ -2.5, -1.5, -0.5, 0.0, 0.5, 1.5 ];
var y = [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ];

acotBy( 3, x, 2, y, -1, accessor );
// y => [ ~1.107, ~-1.107, ~-0.381, 0.0, 0.0, 0.0 ]
`

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' );

function accessor( v ) {
return v;
}

// Initial arrays...
var x0 = new Float64Array( [ -2.5, -1.5, -0.5, 0.0, 0.5, 1.5 ] );
var y0 = new Float64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );

// 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

acotBy( 3, x1, -2, y1, 1, accessor );
// y0 => [ 0.0, 0.0, 0.0, ~0.588, ~1.571, ~-0.588 ]
`

#### acotBy.ndarray( N, x, strideX, offsetX, y, strideY, offsetY, clbk\[, thisArg] )

Computes the [inverse cotangent][@stdlib/math/base/special/acot] of each element retrieved from an input strided array x via a callback function and assigns each result to an element in an output strided array y using alternative indexing semantics.

`javascript
function accessor( v ) {
return v;
}

var x = [ -2.5, -1.5, -0.5, 0.0, 0.5 ];
var y = [ 0.0, 0.0, 0.0, 0.0, 0.0 ];

acotBy.ndarray( x.length, x, 1, 0, y, 1, 0, accessor );
// y => [ ~-0.381, ~-0.588, ~-1.107, ~1.571, ~1.107 ]
`

The function accepts the following additional arguments:

- 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 offsetX and offsetY parameters support indexing semantics based on starting indices. For example, to index every other value in x starting from the second value and to index the last N elements in y,

`javascript
function accessor( v ) {
return v;
}

var x = [ -2.5, -1.5, -0.5, 0.0, 0.5, 1.5 ];
var y = [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ];

acotBy.ndarray( 3, x, 2, 1, y, -1, y.length-1, accessor );
// y => [ 0.0, 0.0, 0.0, ~0.588, ~1.571, ~-0.588 ]
`