v?Acos

Syntax

FORTRAN:

call vsacos( n, a, y )

call vmsacos( n, a, y, mode )

call vdacos( n, a, y )

call vmdacos( n, a, y, mode )

call vcacos( n, a, y )

call vmcacos( n, a, y, mode )

call vzacos( n, a, y )

call vmzacos( n, a, y, mode )

C:

vsAcos( n, a, y );

vmsAcos( n, a, y, mode );

vdAcos( n, a, y );

vmdAcos( n, a, y, mode );

vcAcos( n, a, y );

vmcAcos( n, a, y, mode );

vzAcos( n, a, y );

vmzAcos( n, a, y, mode );

Include Files

FORTRAN 77: mkl_vml.f77
Fortran 90: mkl_vml.f90
C: mkl_vml_functions.h

Input Parameters

Name	Type	Description
n	FORTRAN 77: INTEGER Fortran 90: INTEGER, INTENT(IN) C: const int	Specifies the number of elements to be calculated.
a	FORTRAN 77: REAL for vsacos, vmsacos DOUBLE PRECISION for vdacos, vmdacos COMPLEX for vcacos, vmcacos DOUBLE COMPLEX for vzacos, vmzacos Fortran 90: REAL, INTENT(IN) for vsacos, vmsacos DOUBLE PRECISION, INTENT(IN) for vdacos, vmdacos COMPLEX, INTENT(IN) for vcacos, vmcacos DOUBLE COMPLEX, INTENT(IN) for vzacos, vmzacos C: const float* for vsAcos, vmsAcos const double* for vdAcos, vmdAcos const MKL_Complex8* for vcAcos, vmcAcos const MKL_Complex16* for vzAcos, vmzAcos	FORTRAN: Array that specifies the input vector a. C: Pointer to an array that contains the input vector a.
mode	FORTRAN 77: INTEGER8 Fortran 90:* INTEGER(KIND=8), INTENT(IN) C: const MKL_INT64	Overrides global VML mode setting for this function call. See vmlSetMode for possible values and their description.

Name

Type

Description

n

FORTRAN 77: INTEGER

Fortran 90: INTEGER, INTENT(IN)

C: const int

Specifies the number of elements to be calculated.

a

FORTRAN 77: REAL for vsacos, vmsacos

DOUBLE PRECISION for vdacos, vmdacos

COMPLEX for vcacos, vmcacos

DOUBLE COMPLEX for vzacos, vmzacos

Fortran 90: REAL, INTENT(IN) for vsacos, vmsacos

DOUBLE PRECISION, INTENT(IN) for vdacos, vmdacos

COMPLEX, INTENT(IN) for vcacos, vmcacos

DOUBLE COMPLEX, INTENT(IN) for vzacos, vmzacos

C: const float* for vsAcos, vmsAcos

const double* for vdAcos, vmdAcos

const MKL_Complex8* for vcAcos, vmcAcos

const MKL_Complex16* for vzAcos, vmzAcos

FORTRAN: Array that specifies the input vector a.

C: Pointer to an array that contains the input vector a.

mode

FORTRAN 77: INTEGER*8

Fortran 90: INTEGER(KIND=8), INTENT(IN)

C: const MKL_INT64

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

Output Parameters

Name	Type	Description
y	FORTRAN 77: REAL for vsacos, vmsacos DOUBLE PRECISION for vdacos, vmdacos COMPLEX for vcacos, vmcacos DOUBLE COMPLEX for vzacos, vmzacos Fortran 90: REAL, INTENT(OUT) for vsacos, vmsacos DOUBLE PRECISION, INTENT(OUT) for vdacos, vmdacos COMPLEX, INTENT(OUT) for vcacos, vmcacos DOUBLE COMPLEX, INTENT(OUT) for vzacos, vmzacos C: float* for vsAcos, vmsAcos double* for vdAcos, vmdAcos MKL_Complex8* for vcAcos, vmcAcos MKL_Complex16* for vzAcos, vmzAcos	FORTRAN: Array that specifies the output vector y. C: Pointer to an array that contains the output vector y.

Name

Type

Description

y

FORTRAN 77: REAL for vsacos, vmsacos

DOUBLE PRECISION for vdacos, vmdacos

COMPLEX for vcacos, vmcacos

DOUBLE COMPLEX for vzacos, vmzacos

Fortran 90: REAL, INTENT(OUT) for vsacos, vmsacos

DOUBLE PRECISION, INTENT(OUT) for vdacos, vmdacos

COMPLEX, INTENT(OUT) for vcacos, vmcacos

DOUBLE COMPLEX, INTENT(OUT) for vzacos, vmzacos

C: float* for vsAcos, vmsAcos

double* for vdAcos, vmdAcos

MKL_Complex8* for vcAcos, vmcAcos

MKL_Complex16* for vzAcos, vmzAcos

FORTRAN: Array that specifies the output vector y.

C: Pointer to an array that contains 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	VML 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)).