Running a calculation in parallel
ORCA can run in multiple processors with the aid of OpenMPI (the recommended version for ORCA 5 is 4.1.1). After installing it and setting the PATH and LD_LIBRARY_PATH variables (what is that? Assigning PATH variables), you can simply run in parallel using the PAL keyword. For instance, a calculation using four processors requires:
!HF DEF2-SVP PAL4
For more than eight processors (!PAL8), the explicit %PAL option has to be used:
!HF DEF2-SVP %PAL NPROCS 16 END
When running calculations in parallel, always use the full path to ORCA:
Always install the OpenMPI version indicated in the Download section!