# atan2¶

Computes four-quadrant inverse tangent of elements of two vectors.

Syntax

Buffer API:

void `atan2`(queue &exec_queue, int64_t n, buffer<T, 1> &a, buffer<T, 1> &b, buffer<T, 1> &y, uint64_t mode = mode::not_defined)

USM API:

event `atan2`(queue &exec_queue, int64_t n, T *a, T *b, T *y, vector_class<event> const &depends = {}, uint64_t mode = mode::not_defined)

`ad2d` supports the following precisions and devices:

T

Devices supported

`float`

Host, CPU, and GPU

`double`

Host, CPU, and GPU

Description

The atan2(a,b) function computes four-quadrant inverse tangent of elements of two vectors.

The elements of the output vectory are computed as the four-quadrant arctangent of `a[i] / b[i]`.

Argument 1

Argument 2

Result

Error Code

-∞

-∞

-3*`π`/4

-∞

b < +0

-`π`/2

-∞

-0

-`π`/2

-∞

+0

-`π`/2

-∞

b > +0

-`π`/2

-∞

+∞

-`π`/4

a < +0

-∞

-`π`

a < +0

-0

-`π`/2

a < +0

+0

-`π`/2

a < +0

+∞

-0

-0

-∞

-`π`

-0

b < +0

-`π`

-0

-0

-`π`

-0

+0

-0

-0

b > +0

-0

-0

+∞

-0

+0

-∞

+`π`

+0

b < +0

+`π`

+0

-0

+`π`

+0

+0

+0

+0

b > +0

+0

+0

+∞

+0

a > +0

-∞

+`π`

a > +0

-0

+`π`/2

a > +0

+0

+`π`/2

a > +0

+∞

+0

+∞

-∞

+3*`π`/4

+∞

b < +0

+`π`/2

+∞

-0

+`π`/2

+∞

+0

+`π`/2

+∞

b > +0

+`π`/2

+∞

+∞

+`π`/4

a > +0

QNAN

QNAN

a > +0

SNAN

QNAN

QNAN

b > +0

QNAN

SNAN

b > +0

QNAN

QNAN

QNAN

QNAN

QNAN

SNAN

QNAN

SNAN

QNAN

QNAN

SNAN

SNAN

QNAN

The atan2(a,b) function does not generate any errors.

Input Parameters

Buffer API:

exec_queue

The queue where the routine should be executed.

n

Specifies the number of elements to be calculated.

a

The buffer `a` containing 1st input vector of size `n`.

b

The buffer `b` containing 2nd input vector of size `n`.

mode

Overrides the global VM mode setting for this function call. See set_mode function for possible values and their description. This is an optional parameter. The default value is `mode::not_defined`.

USM API:

exec_queue

The queue where the routine should be executed.

n

Specifies the number of elements to be calculated.

a

Pointer `a` to the 1st input vector of size `n`.

b

Pointer `b` to the 2nd input vector of size `n`.

depends

Vector of dependent events (to wait for input data to be ready).

mode

Overrides the global VM mode setting for this function call. See the set_mode function for possible values and their description. This is an optional parameter. The default value is `mode::not_defined`.

Output Parameters

Buffer API:

y

The buffer `y` containing the output vector of size `n`.

USM API:

y

Pointer `y` to the output vector of size `n`.

return value (event)

Function end event.

Example

An example of how to use atan2can be found in the Intel® oneMKL installation directory, under:

```examples/sycl/vml/vatan2.cpp
```