Intel® Math Kernel Library 2019 Developer Reference - Fortran

v?Atan

Computes inverse tangent of vector elements.

Syntax

call vsatan( n, a, y )

call vmsatan( n, a, y, mode )

call vdatan( n, a, y )

call vmdatan( n, a, y, mode )

call vcatan( n, a, y )

call vmcatan( n, a, y, mode )

call vzatan( n, a, y )

call vmzatan( n, a, y, mode )

Include Files

Input Parameters

Name

Type

Description

n

INTEGER, INTENT(IN)

Specifies the number of elements to be calculated.

a

DOUBLE PRECISION for vdatan, vmdatan

COMPLEX for vcatan, vmcatan

DOUBLE COMPLEX for vzatan, vmzatan

REAL, INTENT(IN) for vsatan, vmsatan

DOUBLE PRECISION, INTENT(IN) for vdatan, vmdatan

COMPLEX, INTENT(IN) for vcatan, vmcatan

DOUBLE COMPLEX, INTENT(IN) for vzatan, vmzatan

Array that specifies the input vector a.

mode

INTEGER(KIND=8), INTENT(IN)

Overrides global VM mode setting for this function call. See vmlSetMode for possible values and their description.

Output Parameters

Name

Type

Description

y

DOUBLE PRECISION for vdatan, vmdatan

COMPLEX for vcatan, vmcatan

DOUBLE COMPLEX for vzatan, vmzatan

REAL, INTENT(OUT) for vsatan, vmsatan

DOUBLE PRECISION, INTENT(OUT) for vdatan, vmdatan

COMPLEX, INTENT(OUT) for vcatan, vmcatan

DOUBLE COMPLEX, INTENT(OUT) for vzatan, vmzatan

Array that specifies the output vector y.

Description

The v?Atan function computes inverse tangent of vector elements.

Special Values for Real Function v?Atan(x)
Argument Result VM Error Status Exception
+0 +0    
-0 -0    
+ +π/2    
- -π/2    
QNAN QNAN    
SNAN QNAN   INVALID

Specifications for special values of the complex functions are defined according to the following formula

Atan(z) = -i*Atanh(i*z).