I am trying to run lammps in parallel on windows and installed microsoft mpi on my pc. BUt when I run the command mpiexec -np 4 lmp_mpi -in input, I get mpich2mpi.dll is missing. Please advise. I am using lammps version LAMMPS 64-bit 1Sep2017-MPI.
Have you tried to use the MPICH (installer link is available in LAMMPS website http://rpm.lammps.org/windows.html) instead of microsoft MPI?
In my case MPICH works well.
For 32-bit mpich2-1.4.1p1-win-ia32.msi
For 64-bit mpich2-1.4.1p1-win-x86-64.msi
Thank for your response. Actually I did try with as you suggest, but mpi fails to launch lammps.
Did you uninstall the microsoft mpi before executing lammps?
In my experience I need to remove microsoft mpi first, so that MPICH can be run properly.