New to LBM and OpenLB? Attend our upcoming one-week hands-on Spring School in Marseille/France from 19.05.2025 – 23.05.2025. OpenLB – Open Source Lattice Boltzmann Code › Forums › on OpenLB › General Topics › Number of threads in MPI paralellization › Re: Number of threads in MPI paralellization July 19, 2012 at 7:49 am #2055 kulkaMember To use 4 cores you should run mpirun(or mpiexec) -np=4 ./cylinder3d