Contents

# atan2

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

## Description

The
atan2(a,b)
function computes four-quadrant inverse tangent of elements of two vectors.
The elements of the output vector
y
are computed as the four-quadrant arctangent of
a[i] / b[i]
.
Argument 1
Argument 2
Result
Error Code
-
-
-
b < +0
-/2
-
-0
-/2
-
+0
-/2
-
b > +0
-/2
-
+
-/4
a < +0
-
-
a < +0
-0
-/2
a < +0
+0
-/2
a < +0
+
-0
-0
-
-
-0
b < +0
-
-0
-0
-
-0
+0
-0
-0
b > +0
-0
-0
+
-0
+0
-
+
+0
b < +0
+
+0
-0
+
+0
+0
+0
+0
b > +0
+0
+0
+
+0
a > +0
-
+
a > +0
-0
+/2
a > +0
+0
+/2
a > +0
+
+0
+
-
+3*/4
+
b < +0
+/2
+
-0
+/2
+
+0
+/2
+
b > +0
+/2
+
+
+/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.

## API

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

sycl::event atan2(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 atan2(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 atan2(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 atan2(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);

}``````
atan2
supports the following precisions and devices:
T
Devices supported
float
Host, CPU, and GPU
double
Host, CPU, and GPU
Description
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
atan2
can be found in the oneMKL installation directory, under:
``examples/dpcpp/vml/source/vatan2.cpp``

#### Product and Performance Information

1

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