Intel® Math Kernel Library 2019 Developer Reference - Fortran
Computes the exponents of the elements of input vector a.
call vslogb (n, a, y)
call vmslogb (n, a, y, mode)
call vdlogb (n, a, y)
call vmdlogb (n, a, y, mode)
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. |
mode |
INTEGER (KIND=8) |
Overrides the global VM mode setting for this function call. See vmlSetMode for possible values and their description. |
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. |
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:
| Argument | Result | VM Error Status | Exception |
|---|---|---|---|
| +0 | -∞ | VML_STATUS_ERRDOM | ZERODIVIDE |
| -0 | -∞ | VML_STATUS_ERRDOM | ZERODIVIDE |
| -∞ | +∞ | ||
| +∞ | +∞ | ||
| QNAN | QNAN | ||
| SNAN | QNAN | INVALID |