Developer Reference for Intel® oneAPI Math Kernel Library for Fortran
v?Log2
Computes the base 2 logarithm of vector elements.
Syntax
call vslog2 ( n , a , y )
call vslog2i(n, a, inca, y, incy)
call vmslog2 ( n , a , y , mode )
call vmslog2i(n, a, inca, y, incy, mode)
call vdlog2 ( n , a , y )
call vdlog2i(n, a, inca, y, incy)
call vmdlog2 ( n , a , y , mode )
call vmdlog2i(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 vslog2 REAL for vmslog2 DOUBLE PRECISION for vdlog2 DOUBLE PRECISION for vmdlog2 |
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 (Sets a new mode for VM functions according to the mode parameter and stores the previous VM mode to oldmode.) for possible values and their description. |
Output Parameters
Name |
Type |
Description |
|---|---|---|
y |
REAL for vslog2 REAL for vmslog2 DOUBLE PRECISION for vdlog2 DOUBLE PRECISION for vmdlog2 |
Pointer to an array containing the output vector y . |
Description
The v?Log2 function computes the base 2 logarithm of vector elements.
See Special Value Notations for the conventions used in this table:
Special values for Real Function v?Log2(x)
Argument |
Result |
VM Error Status |
Exception |
|---|---|---|---|
+1 |
+0 |
||
x < +0 |
QNAN |
VML_STATUS_ERRDOM |
INVALID |
+0 |
|
VML_STATUS_SING |
ZERODIVIDE |
-0 |
|
VML_STATUS_SING |
ZERODIVIDE |
|
QNAN |
VML_STATUS_ERRDOM |
INVALID |
|
|
||
QNAN |
QNAN |
||
SNAN |
QNAN |
INVALID |