Dear user I hope you are doing well. I am having troubles when using parallel distribution to run my python script using kwant. I went through kwant discuss mailing list and tried to read about similar issues. I have red for instance the comment made by hristoph Groth Mon, 08 *Aug 2016 08:12:46 -0700.* *add "from mpi4py import MPI" in the preamble,• substitute kwant.smatrix(…) -> kwant.smatrix(…, comm=MPI.COMM_WORLD), • execute the script using "mpiexec", * I have got an error while using kwant.smatrix(comm=MPI.COMM_WORLD). kwant does not recognize comm TypeError: got an unexpected keyword argument 'comm' I have also tried without comm but with the following command OMP_NUM_THREADS=1 mpiexec -n 4 python file.py or mpirun.openmpi -n 4 -x OMP_NUM_THREADS=1 python file.py but I got the result 4 times Regards BELAYADI