v?Acos

Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

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ID 766686

Date 3/31/2023

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Public

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v?Acos

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	INTEGER, INTENT(IN)	Specifies the number of elements to be calculated.
a	DOUBLE PRECISION for vdacos, vmdacos COMPLEX for vcacos, vmcacos DOUBLE COMPLEX for vzacos, vmzacos 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	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 for possible values and their description.

Output Parameters

Name	Type	Description
y	DOUBLE PRECISION for vdacos, vmdacos COMPLEX for vcacos, vmcacos DOUBLE COMPLEX for vzacos, vmzacos 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	Array that specifies the output vector y.

Name

Type

Description

DOUBLE PRECISION for vdacos, vmdacos

COMPLEX for vcacos, vmcacos

DOUBLE COMPLEX for vzacos, vmzacos

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

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)).

Parent topic: Trigonometric Functions

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Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

v?Acos