Developer Reference

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
a
i
of vector
a
, this is the integral part of log
2
|
a
i
|. 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

Product and Performance Information

1

Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.

Notice revision #20110804