I am building lammps on a new HPC with PKG_OMP=ON using Cmake.
It says OpenMP has been found and configured, and after running CMAKE, it says -- Enabled packages: CLASS2;DIPOLE;KSPACE;MOLECULE;OPENMP
When run make and install, no flags are produced, and I can see it building some omp enabled pair styles like pair_lj_long_coul_long_omp.
But then when I check the executable with lmp -h, most (but not all) of the omp pair styles like lj/class2/coul/long/omp are missing, and the
“Installed Packages” section does NOT have OPENMP in it, and LAMMPS gives me errors that say “ERROR: Package omp command without OPENMP package installed (src/input.cpp:1721)”
Impossible to say for certain without knowing more details and essentially being able to look over your shoulder.
The most common issue would be that you have a different LAMMPS executable somewhere in your path and either the installed directory is missing or somewhere later in your path. You can do two things to check this:
try typing: which lmp or type lmp. Does it point to the expected folder where you installed LAMMPS?
try typing in the build folder: ./lmp -h. Does it show the expected output?
Also: if you type lmp -h, does it show the expected version of LAMMPS?