v?Atan2pi

Developer Reference for Intel® oneAPI Math Kernel Library for C

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ID 766684

Date 12/16/2022

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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`.

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

Parent topic: Trigonometric Functions

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v?Atan2pi

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