v?Acos

Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

Download PDF

ID 766686

Date 4/28/2026

Version

Public

v?Acos

vsAcos vdAcos vcAcos vzAcos vmsAcos vmdAcos vmcAcos vmzAcos Computes inverse cosine of vector elements.

Syntax

call vsacos ( n , a , y )

call vsacosi(n, a, inca, y, incy)

call vmsacos ( n , a , y , mode )

call vmsacosi(n, a, inca, y, incy, mode)

call vdacos ( n , a , y )

call vdacosi(n, a, inca, y, incy)

call vmdacos ( n , a , y , mode )

call vmdacosi(n, a, inca, y, incy, mode)

call vcacos ( n , a , y )

call vcacosi(n, a, inca, y, incy)

call vmcacos ( n , a , y , mode )

call vmcacosi(n, a, inca, y, incy, mode)

call vzacos ( n , a , y )

call vzacosi(n, a, inca, y, incy)

call vmzacos ( n , a , y , mode )

call vmzacosi(n, a, inca, y, incy, mode)

Include Files

mkl_vml.f90

Input Parameters

Name	Type	Description
`n`		Specifies the number of elements to be calculated.
`a`	Fortran 77: DOUBLE PRECISION for `vdacos` , `vmdacos`Fortran 77: COMPLEX for `vcacos` , `vmcacos`Fortran 77: DOUBLE COMPLEX for `vzacos` , `vmzacos`Fortran 90: REAL , INTENT(IN) for `vsacos` , `vmsacos`Fortran 90: DOUBLE PRECISION , INTENT(IN) for `vdacos` , `vmdacos`Fortran 90: COMPLEX , INTENT(IN) for `vcacos` , `vmcacos`Fortran 90: DOUBLE COMPLEX , INTENT(IN) for `vzacos` , `vmzacos`	Array that specifies the input vector `a` .
`inca` , `incy`	INTEGER, INTENT(IN)	Specifies increments for the elements of `a` and `y` .
`mode`	INTEGER(KIND=8) , INTENT(IN)	Overrides global VM mode setting for this function call. See vmlSetMode (Sets a new mode for VM functions according to the mode parameter and stores the previous VM mode to oldmode.) for possible values and their description.

Output Parameters

Name	Type	Description
`y`	Fortran 77: DOUBLE PRECISION for `vdacos` , `vmdacos`Fortran 77: COMPLEX for `vcacos` , `vmcacos`Fortran 77: DOUBLE COMPLEX for `vzacos` , `vmzacos`Fortran 90: REAL , INTENT(OUT) for `vsacos` , `vmsacos`Fortran 90: DOUBLE PRECISION , INTENT(OUT) for `vdacos` , `vmdacos`Fortran 90: COMPLEX , INTENT(OUT) for `vcacos` , `vmcacos`Fortran 90: DOUBLE COMPLEX , INTENT(OUT) for `vzacos` , `vmzacos`	Array that specifies the output vector `y` .

Description

The v?Acos function computes inverse cosine of vector elements.

Special Values for Real Function v?Acos(x)

Argument	Result	VM Error Status	Exception
+0	`π` /2
-0	`π` /2
+1	+0
-1	`π`
`\(\|X\| > 1\)`	QNAN	VML_STATUS_ERRDOM	INVALID
∞	QNAN	VML_STATUS_ERRDOM	INVALID
∞	QNAN	VML_STATUS_ERRDOM	INVALID
QNAN	QNAN
SNAN	QNAN		INVALID

See Special Value Notations for the conventions used in the table below.

Special Values for Complex Function v?Acos(z)

RE(z) i · IM(z)	∞	-X	-0	+0	+X	∞	NAN
+i · ∞	+3 · `π` /4-i · ∞	`π` /2-i · ∞	`π` /2-i · ∞	`π` /2-i · ∞	`π` /2-i · ∞	`π` /4-i · ∞	QNAN-i · ∞
+i · Y	`π` -i · ∞					+0-i · ∞	QNAN+i · QNAN
+i · 0	`π` -i · ∞		`π` /2-i · 0	`π` /2-i · 0		+0-i · ∞	QNAN+i · QNAN
-i · 0	`π` +i · ∞		`π` /2+i · 0	`π` /2+i · 0		+0+i · ∞	QNAN+i · QNAN
-i · Y	`π` +i · ∞					+0+i · ∞	QNAN+i · QNAN
-i · ∞	+3 `π` /4+i · ∞	`π` /2+i · ∞	`π` /2+i · ∞	`π` /2+i · ∞	`π` /2+i · ∞	`π` /4+i · ∞	QNAN+i · ∞
+i · NAN	QNAN+i · ∞	QNAN+i · QNAN	`π` /2+i · QNAN	`π` /2+i · QNAN	QNAN+i · QNAN	QNAN+i · ∞	QNAN+i · QNAN

Notes:

raises INVALID exception when real or imaginary part of the argument is SNAN
\(Acos(CONJ(z))=CONJ(Acos(z))\) .

Select Your Language

Using Intel.com Search

Quick Links

Recent Searches

Advanced Search

Only search in

Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

v?Acos

Syntax

Include Files

Input Parameters

Output Parameters

Description