Developer Reference

  • 2020.2
  • 07/15/2020
  • Public Content
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
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