Intel® Math Kernel Library 2019 Developer Reference - Fortran

v?Log1p

Computes a natural logarithm of vector elements that are increased by 1.

Syntax

call vslog1p( n, a, y )

call vmslog1p( n, a, y, mode )

call vdlog1p( n, a, y )

call vmdlog1p( 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 vdlog1p, vmdlog1p

REAL, INTENT(IN) for vslog1p, vmslog1p

DOUBLE PRECISION, INTENT(IN) for vdlog1p, vmdlog1p

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 vdlog1p, vmdlog1p

REAL, INTENT(OUT) for vslog1p, vmslog1p

DOUBLE PRECISION, INTENT(OUT) for vdlog1p, vmdlog1p

Array that specifies the output vector y.

Description

The v?Log1p function computes a natural logarithm of vector elements that are increased by 1.

Special Values for Real Function v?Log1p(x)
Argument Result VM Error Status Exception
-1 - VML_STATUS_SING ZERODIVIDE
X < -1 QNAN VML_STATUS_ERRDOM INVALID
+0 +0    
-0 -0    
- QNAN VML_STATUS_ERRDOM INVALID
+ +    
QNAN QNAN    
SNAN QNAN   INVALID