v?Atan2

Developer Reference for Intel® oneAPI Math Kernel Library for C

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ID 766684

Date 12/16/2022

Version

Public

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

Syntax

vsAtan2( n, a, b, y );

vsAtan2I(n, a, inca, b, incb, y, incy);

vmsAtan2( n, a, b, y, mode );

vmsAtan2I(n, a, inca, b, incb, y, incy, mode);

vdAtan2( n, a, b, y );

vdAtan2I(n, a, inca, b, incb, y, incy);

vmdAtan2( n, a, b, y, mode );

vmdAtan2I(n, a, inca, b, incb, y, incy, mode);

Include Files

Input Parameters

Name	Type	Description
n	const MKL_INT	Specifies the number of elements to be calculated.
a, b	const float* for vsAtan2, vmsAtan2 const double* for vdAtan2, vmdAtan2	Pointers to arrays that contain 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 global VM mode setting for this function call. See vmlSetMode for possible values and their description.

Output Parameters

Name	Type	Description
y	float* for vsAtan2, vmsAtan2 double* for vdAtan2, vmdAtan2	Pointer to an array that contains the output vector y.

Name

Type

Description

float* for vsAtan2, vmsAtan2

double* for vdAtan2, vmdAtan2

Pointer to an array that contains the output vector y.

Description

The v?Atan2 function computes four-quadrant inverse tangent of elements of two vectors.

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

Special values for Real Function v?Atan2(x)
Argument 1	Argument 2	Result	Exception
-∞	-∞	-3*`π`/4
-∞	X < +0	-`π`/2
-∞	-0	-`π`/2
-∞	+0	-`π`/2
-∞	X > +0	-`π`/2
-∞	+∞	-`π`/4
X < +0	-∞	-`π`
X < +0	-0	-`π`/2
X < +0	+0	-`π`/2
X < +0	+∞	-0
-0	-∞	-`π`
-0	X < +0	-`π`
-0	-0	-`π`
-0	+0	-0
-0	X > +0	-0
-0	+∞	-0
+0	-∞	+`π`
+0	X < +0	+`π`
+0	-0	+`π`
+0	+0	+0
+0	X > +0	+0
+0	+∞	+0
X > +0	-∞	+`π`
X > +0	-0	+`π`/2
X > +0	+0	+`π`/2
X > +0	+∞	+0
+∞	-∞	+3*`π`/4
+∞	X < +0	+`π`/2
+∞	-0	+`π`/2
+∞	+0	+`π`/2
+∞	X > +0	+`π`/2
+∞	+∞	+`π`/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

Parent topic: Trigonometric Functions