# How to run PyFR on CPU/multicores only \[ Without CUDA/OPENCL\]

**URL:** <https://pyfr.discourse.group/t/how-to-run-pyfr-on-cpu-multicores-only-without-cuda-opencl/81>\
**Category:** General\
**Created:** [6 July 2015 08:27 UTC](https://pyfr.discourse.group/t/how-to-run-pyfr-on-cpu-multicores-only-without-cuda-opencl/81 "2015-07-06T08:27:55Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Roshan\_Tayde](https://avatars.discourse-cdn.com/v4/letter/r/e79b87/32.png) [@Roshan\_Tayde](https://pyfr.discourse.group/u/Roshan_Tayde)\
**Post date:** [6 July 2015 08:27 UTC](https://pyfr.discourse.group/t/how-to-run-pyfr-on-cpu-multicores-only-without-cuda-opencl/81/1 "2015-07-06T08:27:55Z")

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Hi everyone,

I installed PyFR successfully for bench-marking purpose. First I installed it with all its dependencies including CUDA and OPENCL.  
When I run it , it was started executing on CPU + GPU , and it ran successfully.  
But now I want to run it on CPU only, so I installed it on a multi-cores machine which is not having any GPU card, without OPENCL and CUDA dependencies.

When I am trying to run it, with " mpirun -n 4 pyfr run couette\_flow\_2d.pyfrm couette\_flow\_2d.ini" command  
it gives following error :

ImportError: No module named ‘pycuda’

So I want to know , how to run it on multi-cores with MPI.

Regards,  
Roshan

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**Author:** ![fdw](https://avatars.discourse-cdn.com/v4/letter/f/a587f6/32.png) [@fdw](https://pyfr.discourse.group/u/fdw)\
**Post date:** [6 July 2015 09:58 UTC](https://pyfr.discourse.group/t/how-to-run-pyfr-on-cpu-multicores-only-without-cuda-opencl/81/2 "2015-07-06T09:58:11Z")

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Hi Roshan,

As per the documentation to run PyFR on a CPU using the OpenMP backend  
you need to pass -b openmp to $ pyfr. Otherwise, PyFR will run using  
the CUDA backend on an NVIDIA GPU.

Regards, Freddie.

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**Author:** ![Roshan\_Tayde](https://avatars.discourse-cdn.com/v4/letter/r/e79b87/32.png) [@Roshan\_Tayde](https://pyfr.discourse.group/u/Roshan_Tayde)\
**Post date:** [6 July 2015 13:41 UTC](https://pyfr.discourse.group/t/how-to-run-pyfr-on-cpu-multicores-only-without-cuda-opencl/81/3 "2015-07-06T13:41:46Z")

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Thank you Freddie,  
It worked, thanks for your suggestion.  
I am trying to benchmark PyFR , please suggest some datatsets or provide me the link for that, so I can take benchmark of PyFR.  
waiting for your reply.

Regards,  
Roshan

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**Author:** ![fdw](https://avatars.discourse-cdn.com/v4/letter/f/a587f6/32.png) [@fdw](https://pyfr.discourse.group/u/fdw)\
**Post date:** [6 July 2015 13:54 UTC](https://pyfr.discourse.group/t/how-to-run-pyfr-on-cpu-multicores-only-without-cuda-opencl/81/4 "2015-07-06T13:54:03Z")

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Hi Roshan,

Suitable sample data sets and configuration files can be found in the  
following series of posts on the mailing list:

[example datasets](https://pyfr.discourse.group/t/example-datasets/57/2)

(Look for the post by Jin Seok.)

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**Author:** ![Roshan\_Tayde](https://avatars.discourse-cdn.com/v4/letter/r/e79b87/32.png) [@Roshan\_Tayde](https://pyfr.discourse.group/u/Roshan_Tayde)\
**Post date:** [8 July 2015 09:04 UTC](https://pyfr.discourse.group/t/how-to-run-pyfr-on-cpu-multicores-only-without-cuda-opencl/81/5 "2015-07-08T09:04:45Z")

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Thank you Freddie !!! once again …

Regards,  
Roshan