Setting the Default Mode of Vector Math with an Environment Variable
Intel® oneAPI Math Kernel Library (oneMKL)
MKL_VML_MODE
environment variable.
Because the mode is set or can be changed in different ways, their precedence determines the actual mode used. The settings and function calls that set or change the VM mode are listed below, with the precedence growing from lowest to highest:
- The default setting
- TheMKL_VML_MODEenvironment variable
- A callvmlSetModefunction
- A call to any VM function other than a service function
For more details, see the Vector Mathematical Functions section in the
Developer Reference and the description of the
Intel® oneAPI Math Kernel Library
vmlSetMode
function in particular.
To set the
MKL_VML_MODE
environment variable, use the following command:
set MKL_VML_MODE=
<mode-string>
In
controls error handling behavior and computation accuracy, consists of one or several comma-separated values of the
this
command,
<mode-string>
mode
parameter listed in the table below, and meets these requirements:
- Not more than one accuracy control value is permitted
- Any combination of error control values exceptVML_ERRMODE_DEFAULTis permitted
- No denormalized numbers control values are permitted
Value of
mode | Description
|
---|---|
Accuracy Control
| |
VML_HA | high accuracy versions of VM functions
|
VML_LA | low accuracy versions of VM functions
|
VML_EP | enhanced performance accuracy versions of VM functions
|
Denormalized Numbers Handling Control
| |
VML_FTZDAZ_ON | Faster processing of denormalized inputs is enabled.
|
VML_FTZDAZ_OFF | Faster processing of denormalized inputs is disabled.
|
VML_FTZDAZ_CURRENT | Keep the current CPU settings for denormalized inputs.
|
Error Mode Control
| |
VML_ERRMODE_IGNORE | On computation error, VM Error status is updated, but otherwise no action is set. Cannot be combined with other
VML_ERRMODE settings.
|
VML_ERRMODE_NOERR | On computation error, VM Error status is not updated and no action is set. Cannot be combined with other
VML_ERRMODE settings.
|
VML_ERRMODE_STDERR | On error, the error text information is written to
stderr .
|
VML_ERRMODE_EXCEPT | On error, an exception is raised.
|
VML_ERRMODE_CALLBACK | On error, an additional error handler function is called.
|
VML_ERRMODE_DEFAULT | On error,
an exception is raised and an additional error handler function is called.
|
This
command provides
an example of valid settings for the
MKL_VML_MODE
environment variable:
set MKL_VML_MODE=VML_LA,VML_ERRMODE_ERRNO,VML_ERRMODE_STDERR
VM ignores the
MKL_VML_MODE
environment variable in the case of incorrect or misspelled settings of
mode
.