Developer Reference for Intel® oneAPI Math Kernel Library for C

ID 766684
Date 12/16/2022
Public

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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.

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 ai/bi, 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

See Also