topic Thanks Robert, I was missing in Intel® Distribution for Python*

Configure number of processors available to MKL NumPy

Gilbert_F_ — Mon, 10 Aug 2015 16:07:51 GMT

Is there a config file or a command line parameter to set the number of available processors for MKLnumpy to take advantage of?

Thanks

Welcome to the forum and

Anton_M_Intel — Mon, 10 Aug 2015 21:27:00 GMT

Welcome to the forum and thank you for the question!

MKL uses the best number of threads by default, e.g. (on Windows):

> python -c "import ctypes; mkl_rt = ctypes.CDLL('mkl_rt.dll'); print mkl_rt.mkl_get_max_threads()"
16

If you want to change it, set MKL_NUM_THREADS environment variable to specify the number of threads to run in parallel, e.g.:

> set MKL_NUM_THREADS=1
> python -c "import ctypes; mkl_rt = ctypes.CDLL('mkl_rt.dll'); print mkl_rt.mkl_get_max_threads()"
1

Please see this blog for more information regarding recommended environment variable settings for multithreading MKL. Or refer to MKL threading control API here.

Quote:Anton Malakhov (Intel)

RL5 — Fri, 17 Feb 2017 10:19:53 GMT

Anton Malakhov (Intel) wrote:

> python -c "import ctypes; mkl_rt = ctypes.CDLL('mkl_rt.dll'); print mkl_rt.mkl_get_max_threads()"
16

How does one check the number of threads in linux?

For linux, you need to change

Robert_C_Intel — Fri, 17 Feb 2017 13:05:38 GMT

For linux, you need to change the name of the shared library:
python -c "import ctypes; mkl_rt = ctypes.CDLL('libmkl_rt.so'); print(mkl_rt.mkl_get_max_threads())"

Thanks Robert, I was missing

RL5 — Fri, 17 Feb 2017 14:22:41 GMT

Thanks Robert, I was missing the 'lib' part of the name.

For future reference, on a

Zhanwen_C_ — Fri, 05 Apr 2019 15:16:10 GMT

For future reference, on a Mac you simply change "mkl_rt.dll"/"libmkl_rt.so" to "libmkl_rt.dylib", like so:

```python

python -c "import ctypes; mkl_rt = ctypes.CDLL('libmkl_rt.dylib'); print(mkl_rt.mkl_get_max_threads())"

```