Contents

# atan2pi

Computes the element-wise four-quadrant arctangent of vector
a
elements divided by vector
b
elements, divided by pi.

## Description

The
atan2pi(a,b)
function computes the four-quadrant inverse tangent of the ratios of the corresponding elements of two vectors divided by .
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 .
Argument 1
Argument 2
Result
Error 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.

## API

Syntax
Buffer API
``````namespace oneapi::mkl::vm {

sycl::event atan2pi(sycl::queue & exec_queue,
std::int64_t n,
sycl::buffer<T> & a,
sycl::buffer<T> & b,
sycl::buffer<T> & y,
oneapi::mkl::vm::mode mode = oneapi::mkl::vm::mode::not_defined);

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

sycl::event atan2pi(sycl::queue & exec_queue,
sycl::buffer<T> & a,
oneapi::mkl::slice sa,
sycl::buffer<T> & b,
oneapi::mkl::slice sb,
sycl::buffer<T> & y,
oneapi::mkl::slice sy,
oneapi::mkl::vm::mode mode = oneapi::mkl::vm::mode::not_defined);

}``````
USM API
``````namespace oneapi::mkl::vm {

sycl::event atan2pi(sycl::queue & exec_queue,
std::int64_t n,
T const * a,
T const * b,
T * y,
std::vector<cl::sycl::event> const & depends = {},
oneapi::mkl::vm::mode mode = oneapi::mkl::vm::mode::not_defined);

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

sycl::event atan2pi(sycl::queue & exec_queue,
T const * a,
oneapi::mkl::slice sa,
T const * b,
oneapi::mkl::slice sb,
T * y,
oneapi::mkl::slice sy,
std::vector<cl::sycl::event> const & depends = {},
oneapi::mkl::vm::mode mode = oneapi::mkl::vm::mode::not_defined);

}``````
atan2pi
supports the following precisions and devices:
T
Devices supported
float
Host, CPU, and GPU
double
Host, CPU, and GPU
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 containing the 1st input vector.
sa
Slice selector for
a
. See Data Types for a description of the oneMKL slice type.
b
The buffer containing the 2nd input vector.
sb
Slice selector for
b
. See Data Types for a description of the oneMKL slice type.
sy
Slice selector for
y
. See Data Types for a description of the oneMKL slice type.
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 to the 1st input vector.
sa
Slice selector for
a
. See Data Types for a description of the oneMKL slice type.
b
Pointer to the 2nd input vector.
sb
Slice selector for
b
. See Data Types for a description of the oneMKL slice type.
sy
Slice selector for
y
. See Data Types for a description of the oneMKL slice type.
depends
Vector of dependent events (to wait for input data to be ready). This is an optional parameter. The default is an empty vector.
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 containing the output vector.
return value (event)
Computation end event.
USM API
y
Pointer to the output vector.
return value (event)
Computation end event.

## Examples

An example of how to use
atan2pi
can be found in the oneMKL installation directory, under:
``examples/dpcpp/vml/source/vatan2pi.cpp``

#### Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.