Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

ID 766686
Date 3/22/2024
Public

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Document Table of Contents

v?Logb

Computes the exponents of the elements of input vector a.

Syntax

call vslogb (n, a, y)

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

call vmslogb (n, a, y, mode)

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

call vdlogb (n, a, y)

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

call vmdlogb (n, a, y, mode)

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

Include Files

  • mkl_vml.f90

Input Parameters

Name

Type

Description

n

INTEGER

Specifies the number of elements to be calculated.

a

REAL for vslogb

REAL for vmslogb

DOUBLE PRECISION for vdlogb

DOUBLE PRECISION for vmdlogb

Pointer to the array containing the input vector a.

inca, incy

INTEGER, INTENT(IN)

Specifies increments for the elements of a and y.

mode

INTEGER (KIND=8)

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

Output Parameters

Name

Type

Description

y

REAL for vslogb

REAL for vmslogb

DOUBLE PRECISION for vdlogb

DOUBLE PRECISION for vmdlogb

Pointer to an array containing the output vector y.

Description

The v?Logb function computes the exponents of the elements of the input vector a. For each element ai of vector a, this is the integral part of log2|ai|. The returned value is exact and is independent of the current rounding direction mode.

See Special Value Notations for the conventions used in this table:

Special values for Real Function v?Logb(x)
Argument Result VM Error Status Exception
+0 - VML_STATUS_ERRDOM ZERODIVIDE
-0 - VML_STATUS_ERRDOM ZERODIVIDE
- +    
+ +    
QNAN QNAN    
SNAN QNAN   INVALID