Intel® oneAPI Math Kernel Library

threading layer defines how

Intel® oneAPI Math Kernel Library

functions utilize multiple computing cores of the system that the application runs on. You must link your application with one appropriate

Intel® oneAPI Math Kernel Library

library in this layer, as explained below. Depending on whether this is a threading or a sequential library,

Intel® oneAPI Math Kernel Library

runs in a parallel or sequential mode, respectively.

In the

parallel mode

,

Intel® oneAPI Math Kernel Library

utilizes multiple processor cores available on your system, uses the OpenMP*

or Intel TBB

threading technology, and requires a proper

threading

runtime library (RTL) to be linked with your application. Independently of use of

Intel® oneAPI Math Kernel Library

, the application may also require a threading RTL. You should link not more than one

threading

RTL to your application.

Threading RTLs are

provided by your compiler.

Intel® oneAPI Math Kernel Library

provides several threading libraries, each dependent on the

threading

RTL of a certain compiler, and your choice of the

Intel® oneAPI Math Kernel Library

threading library must be consistent with the

threading

RTL that you use in your application.

The OpenMP RTL of the Intel® compiler is the

libiomp5

md.lib

library, located under

<parent directory>

\

compiler

\

lib

. You can find additional information about the Intel OpenMP RTL at https://www.openmprtl.org.

The Intel TBB RTL of the Intel® compiler is the

tbb

12.lib

library, located under

<parent directory>

\tbb\lib

. You can find additional information about the Intel TBB RTL at https://www.threadingbuildingblocks.org.

In the

sequential mode

,

Intel® oneAPI Math Kernel Library

runs unthreaded code, does not require an

threading

RTL, and does not respond to environment variables and functions controlling the number of threads. Avoid using the library in the sequential mode unless you have a particular reason for that, such as the following:

It is critical to link the application with the proper RTL. The table below explains what library in the

Intel® oneAPI Math Kernel Library

threading layer and what

threading

RTL you should choose under different scenarios: