# atan2¶

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

Syntax

Buffer API:

```namespace oneapi::mkl::vm {

sycl::event atan2(
sycl::queue& exec_queue,
std::int64_t n,
sycl::buffer<T,1>& a,
sycl::buffer<T,1>& b,
sycl::buffer<T,1>& y,
oneapi::mkl::vm::mode mode = oneapi::mkl::vm::mode::not_defined);

} // namespace oneapi::mkl::vm
```

USM API:

```namespace oneapi::mkl::vm {

sycl::event atan2(
sycl::queue& exec_queue,
std::int64_t n,
T* a,
T* b,
T* y,
sycl::vector_class<sycl::event> const & depends = {},
oneapi::mkl::vm::mode mode = oneapi::mkl::vm::mode::not_defined);

} // namespace oneapi::mkl::vm
```

`ad2d` supports the following precisions.

T

`float`

`double`

Description

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

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

Argument 1

Argument 2

Result

Status 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 `oneapi::mkl::vm::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 `oneapi::mkl::vm::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)

Event, signifying availability of computed output and status code(s).

Exceptions

For list of generated exceptions please refer to  Exceptions