# atan2pi¶

Computes the four-quadrant inverse tangent of the ratios of the corresponding elements of two vectors divided by `π`.

Syntax

Buffer API:

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

sycl::event atan2pi(
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 atan2pi(
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
```

`atan2pi` supports the following precisions.

T

`float`

`double`

Description

The atan2pi(a, b) function computes the four-quadrant inverse tangent of the ratios of the corresponding elements of two vectors divided by `π`.

For the elements of the output vector `y`, the function computers the four-quadrant arctangent of `a`i/`b`i, with the result divided by `π`.

Argument 1

Argument 2

Result

Status code

-∞

-∞

-3/4

-∞

`b` < +0

-1/2

-∞

-0

+1/2

-∞

+0

-1/2

-∞

`x` > +0

-1/2

-∞

+∞

-1/4

`a` < +0

-∞

-1

`a` < +0

-0

-1/2

`a` < +0

+0

-1/2

`a` < +0

+∞

-0

-0

-∞

-1

-0

`b` < +0

-1

-0

-0

-1

-0

+0

-0

-0

`b` > +0

-0

-0

+∞

-0

+0

-∞

+1

+0

`b` < +0

+1

+0

-0

+1

+0

+0

+0

+0

`b` > +0

+0

+0

+∞

+0

`a` > +0

-∞

+1

`a` > +0

-0

+1/2

`x` > +0

+0

+1/2

`a` > +0

+∞

+1/4

+∞

-∞

+3/4

+∞

`b` < +0

+1/2

+∞

-0

+1/2

+∞

+0

+1/2

+∞

`b` > +0

+1/2

+∞

+∞

+1/4

`a` > +0

QNAN

QNAN

`a` > +0

SNAN

QNAN

QNAN

`b` > +0

QNAN

SNAN

`x` > +0

QNAN

QNAN

QNAN

QNAN

QNAN

SNAN

QNAN

SNAN

QNAN

QNAN

SNAN

SNAN

QNAN

The atan2pi(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