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Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

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ID 766686

Date 3/31/2023

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v?Ln

Computes natural logarithm of vector elements.

Syntax

call vsln( n, a, y )

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

call vmsln( n, a, y, mode )

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

call vdln( n, a, y )

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

call vmdln( n, a, y, mode )

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

call vcln( n, a, y )

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

call vmcln( n, a, y, mode )

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

call vzln( n, a, y )

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

call vmzln( n, a, y, mode )

call vmzlni(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 vdln, vmdln COMPLEX for vcln, vmcln DOUBLE COMPLEX for vzln, vmzln REAL, INTENT(IN) for vsln, vmsln DOUBLE PRECISION, INTENT(IN) for vdln, vmdln COMPLEX, INTENT(IN) for vcln, vmcln DOUBLE COMPLEX, INTENT(IN) for vzln, vmzln	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 vdln, vmdln COMPLEX for vcln, vmcln DOUBLE COMPLEX for vzln, vmzln REAL, INTENT(OUT) for vsln, vmsln DOUBLE PRECISION, INTENT(OUT) for vdln, vmdln COMPLEX, INTENT(OUT) for vcln, vmcln DOUBLE COMPLEX, INTENT(OUT) for vzln, vmzln	Array that specifies the output vector y.

Name

Type

Description

DOUBLE PRECISION for vdln, vmdln

COMPLEX for vcln, vmcln

DOUBLE COMPLEX for vzln, vmzln

REAL, INTENT(OUT) for vsln, vmsln

DOUBLE PRECISION, INTENT(OUT) for vdln, vmdln

COMPLEX, INTENT(OUT) for vcln, vmcln

DOUBLE COMPLEX, INTENT(OUT) for vzln, vmzln

Array that specifies the output vector y.

Description

The v?Ln function computes natural logarithm of vector elements.

Special Values for Real Function v?Ln(x)
Argument	Result	VM Error Status	Exception
+1	+0
X < +0	QNAN	VML_STATUS_ERRDOM	INVALID
+0	-∞	VML_STATUS_SING	ZERODIVIDE
-0	-∞	VML_STATUS_SING	ZERODIVIDE
-∞	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?Ln(z)
RE(z) i·IM(z)	-∞	-X	-0	+0	+X	+∞	NAN
+i·∞		+∞+i·`π`/2	+∞+i·`π`/2	+∞+i·`π`/2	+∞+i·`π`/2	+∞+i·`π`/4	+∞+i·QNAN
+i·Y	+∞+i·`π`					+∞+i·0	QNAN+i·QNAN INVALID
+i·0	+∞+i·`π`		-∞+i·`π` ZERODIVIDE	-∞+i·0 ZERODIVIDE		+∞+i·0	QNAN+i·QNAN INVALID
-i·0	+∞-i·`π`		-∞-i·`π` ZERODIVIDE	-∞-i·0 ZERODIVIDE		+∞-i·0	QNAN+i·QNAN INVALID
-i·Y	+∞-i·`π`					+∞-i·0	QNAN+i·QNAN INVALID
-i·∞		+∞-i·`π`/2	+∞-i·`π`/2	+∞-i·`π`/2	+∞-i·`π`/2	+∞-i·`π`/4	+∞+i·QNAN
+i·NAN	+∞+i·QNAN	QNAN+i·QNAN INVALID	QNAN+i·QNAN INVALID	QNAN+i·QNAN INVALID	QNAN+i·QNAN INVALID	+∞+i·QNAN	QNAN+i·QNAN INVALID

Notes:

raises INVALID exception when real or imaginary part of the argument is SNAN

Parent topic: Exponential and Logarithmic Functions

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Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

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