Developer Reference for Intel® oneAPI Math Kernel Library - C

Developer Reference

  • 0.9
  • 09/09/2020
  • Public Content
Contents

v?Atan2pi

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

Syntax

vsAtan2pi
(
n
,
a
,
b
,
y
);
vsAtan2piI(n, a, inca, b, incb, y, incy);
vmsAtan2pi
(
n
,
a
,
b
,
y
,
mode
);
vmsAtan2piI(n, a, inca, b, incb, y, incy, mode);
vdAtan2pi
(
n
,
a
,
b
,
y
);
vdAtan2piI(n, a, inca, b, incb, y, incy);
vmdAtan2pi
(
n
,
a
,
b
,
y
,
mode
);
vmdAtan2piI(n, a, inca, b, incb, y, incy, mode);
Include Files
  • mkl.h
Input Parameters
Name
Type
Description
n
const MKL_INT
Specifies the number of elements to be calculated.
a
,
b
const float*
 for
vsAtan2pi
const float*
 for
vmsAtan2pi
const double*
 for
vdAtan2pi
const double*
 for
vmdAtan2pi
Pointers to the arrays containing the input vectors
a
 and
b
.
inca
,
incb
,
incy
const MKL_INT
Specifies increments for the elements of
a
,
b
 and
y
.
mode
const MKL_INT64
Overrides the global VM
mode
 setting for this function call. See
vmlSetMode
 for possible values and their description.
Output Parameters
Name
Type
Description
y
float*
 for
vsAtan2pi
float*
 for
vmsAtan2pi
double*
 for
vdAtan2pi
double*
 for
vmdAtan2pi
Pointer to an array containing the output vector
y
.
Description
The
v?Atan2pi
 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
.
Special values for Real Function
v?Atan2pi(x, y)
Argument 1
Argument 2
Result
Exception
-
∞
-
∞
-3/4
-
∞
x
 < +0
-1/2
-
∞
-0
+1/2
-
∞
+0
-1/2
-
∞
x
 > +0
-1/2
-
∞
+
∞
-1/4
x
 < +0
-
∞
-1
x
 < +0
-0
-1/2
x
 < +0
+0
-1/2
x
 < +0
+
∞
-0
-0
-
∞
-1
-0
x
 < +0
-1
-0
-0
-1
-0
+0
-0
-0
x
 > +0
-0
-0
+
∞
-0
+0
-
∞
+1
+0
x
 < +0
+1
+0
-0
+1
+0
+0
+0
+0
x
 > +0
+0
+0
+
∞
+0
x
 > +0
-
∞
+1
x
 > +0
-0
+1/2
x
 > +0
+0
+1/2
x
 > +0
+
∞
+1/4
+
∞
-
∞
+3/4
+
∞
x
 < +0
+1/2
+
∞
-0
+1/2
+
∞
+0
+1/2
+
∞
x
 > +0
+1/2
+
∞
+
∞
+1/4
x
 > +0
QNAN
QNAN
x
 > +0
SNAN
QNAN
INVALID
QNAN
x
 > +0
QNAN
SNAN
x
 > +0
QNAN
INVALID
QNAN
QNAN
QNAN
QNAN
SNAN
QNAN
INVALID
SNAN
QNAN
QNAN
INVALID
SNAN
SNAN
QNAN
INVALID

Product and Performance Information

1

Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.

Notice revision #20110804