# Runtime error about 2d euler vortex example **URL:** \ **Category:** General\ **Created:** [5 July 2022 05:47 UTC](https://pyfr.discourse.group/t/runtime-error-about-2d-euler-vortex-example/636 "2022-07-05T05:47:23Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![YoonSuKyung](https://avatars.discourse-cdn.com/v4/letter/y/5e9695/32.png) [@YoonSuKyung](https://pyfr.discourse.group/u/YoonSuKyung)\ **Post date:** [5 July 2022 05:47 UTC](https://pyfr.discourse.group/t/runtime-error-about-2d-euler-vortex-example/636/1 "2022-07-05T05:47:23Z")
A few days ago, i update pyfr version (1.13 → 1.14.0) Thereafter the 2D euler vortex example is not executed. ----------------------------error message-------------------- ## (pyfr\_14) sk@sk:~/pyfr/pyfr\_14/PyFR-1.14.0/examples/euler\_vortex\_2d$ mpiexec -n 2 pyfr run -b cuda -p euler\_vortex\_2d.pyfrm euler\_vortex\_2d.ini Traceback (most recent call last): File “/home/sk/pyfr/pyfr\_14/bin/pyfr”, line 33, in sys.exit(load\_entry\_point(‘pyfr==1.14.0’, ‘console\_scripts’, ‘pyfr’)()) File “/home/sk/pyfr/pyfr\_14/lib/python3.9/site-packages/pyfr-1.14.0-py3.9.egg/pyfr/ **main**.py”, line 115, in main File “/home/sk/pyfr/pyfr\_14/lib/python3.9/site-packages/pyfr-1.14.0-py3.9.egg/pyfr/ **main**.py”, line 248, in process\_run File “/home/sk/pyfr/pyfr\_14/lib/python3.9/site-packages/pyfr-1.14.0-py3.9.egg/pyfr/ **main**.py”, line 230, in \_process\_common File “/home/sk/pyfr/pyfr\_14/lib/python3.9/site-packages/pyfr-1.14.0-py3.9.egg/pyfr/rank\_allocator.py”, line 14, in get\_rank\_allocation File “/home/sk/pyfr/pyfr\_14/lib/python3.9/site-packages/pyfr-1.14.0-py3.9.egg/pyfr/rank\_allocator.py”, line 31, in **init** RuntimeError: Mesh has 2 partitions but running with 1 MPI ranks Traceback (most recent call last): File “/home/sk/pyfr/pyfr\_14/bin/pyfr”, line 33, in sys.exit(load\_entry\_point(‘pyfr==1.14.0’, ‘console\_scripts’, ‘pyfr’)()) File “/home/sk/pyfr/pyfr\_14/lib/python3.9/site-packages/pyfr-1.14.0-py3.9.egg/pyfr/ **main**.py”, line 115, in main File “/home/sk/pyfr/pyfr\_14/lib/python3.9/site-packages/pyfr-1.14.0-py3.9.egg/pyfr/ **main**.py”, line 248, in process\_run File “/home/sk/pyfr/pyfr\_14/lib/python3.9/site-packages/pyfr-1.14.0-py3.9.egg/pyfr/ **main**.py”, line 230, in \_process\_common File “/home/sk/pyfr/pyfr\_14/lib/python3.9/site-packages/pyfr-1.14.0-py3.9.egg/pyfr/rank\_allocator.py”, line 14, in get\_rank\_allocation File “/home/sk/pyfr/pyfr\_14/lib/python3.9/site-packages/pyfr-1.14.0-py3.9.egg/pyfr/rank\_allocator.py”, line 31, in **init** RuntimeError: Mesh has 2 partitions but running with 1 MPI ranks I think it is an error related to MPI parallelization What is the cause of the error and how can it be resolved? ---
**Author:** ![WillT](https://avatars.discourse-cdn.com/v4/letter/w/bc79bd/32.png) [@WillT](https://pyfr.discourse.group/u/WillT)\ **Post date:** [5 July 2022 10:25 UTC](https://pyfr.discourse.group/t/runtime-error-about-2d-euler-vortex-example/636/2 "2022-07-05T10:25:04Z")
If seems as though mpi is running the 2 instances of the pyfr command rather than pyfr using two mpi ranks. Did you also update mpi recently? If so you will need to rebuild mpi4py. ---
**Author:** ![YoonSuKyung](https://avatars.discourse-cdn.com/v4/letter/y/5e9695/32.png) [@YoonSuKyung](https://pyfr.discourse.group/u/YoonSuKyung)\ **Post date:** [12 July 2022 02:36 UTC](https://pyfr.discourse.group/t/runtime-error-about-2d-euler-vortex-example/636/3 "2022-07-12T02:36:50Z")
That problem was fixed. Thanks Will ! Additionally, I will build new computer to proceed GPU computing using 4 GPUs. Can i run PyFR in 1 CPU (8 cores) + 4 GPUs (Nvidia) ? ---
**Author:** ![WillT](https://avatars.discourse-cdn.com/v4/letter/w/bc79bd/32.png) [@WillT](https://pyfr.discourse.group/u/WillT)\ **Post date:** [12 July 2022 07:46 UTC](https://pyfr.discourse.group/t/runtime-error-about-2d-euler-vortex-example/636/4 "2022-07-12T07:46:01Z")
Yes, if you run PyFR with a command something like `mpiexec -n 4 pyfr run -b cuda ...` that should do the trick. If you haven’t already it’s probably worth compiling MPI with the CUDA aware flag, see here for more details: [Performance Tuning — Documentation](https://pyfr.readthedocs.io/en/latest/performance_tuning.html#cuda-backend)