Developer Reference for Intel® oneAPI Math Kernel Library for C

ID 766684
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

vsLogb (n, a, y);

vsLogbI(n, a, inca, y, incy);

vmsLogb (n, a, y, mode);

vmsLogbI(n, a, inca, y, incy, mode);

vdLogb (n, a, y);

vdLogbI(n, a, inca, y, incy);

vmdLogb (n, a, y, mode);

vmdLogbI(n, a, inca, y, incy, mode);

Include Files

  • mkl.h

Input Parameters

Name

Type

Description

n

const MKL_INT

Specifies the number of elements to be calculated.

a

const float* for vsLogb

const float* for vmsLogb

const double* for vdLogb

const double* for vmdLogb

Pointer to the array containing the input vector a.

inca, incy

const MKL_INT

Specifies increments for the elements of a and y.

mode

const MKL_INT64

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

Output Parameters

Name

Type

Description

y

float* for vsLogb

float* for vmsLogb

double* for vdLogb

double* 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