MPI GPU compilation fails

[Mulgish]

I am trying to follow the steps for compiling this add-on for CUDA and it looks like it does not compile due to missing enums.

Is CUDA implementation complete at all?

I am getting below error after running make -j mpi_gpu:

Compiling LAMMPS for machine mpi_gpu
make[1]: Entering directory '/home/docker/lammps/src/Obj_mpi_gpu'
make[1]: Leaving directory '/home/docker/lammps/src/Obj_mpi_gpu'
make[1]: Entering directory '/home/docker/lammps/src/Obj_mpi_gpu'
mpicxx -g -O3 -std=c++11 -DFIX_EPH_GPU  -DLAMMPS_GZIP -DLAMMPS_MEMALIGN=64   -DLMP_GPU  -DMPICH_SKIP_MPICXX -DOMPI_SKIP_MPICXX=1      -c ../fix_eph_gpu.cpp
../fix_eph_gpu.cpp: In member function ‘virtual void LAMMPS_NS::FixEPHGPU::post_force(int)’:
../fix_eph_gpu.cpp:137:23: error: ‘XIX’ is not a member of ‘LAMMPS_NS::FixEPH::FixState’; did you mean ‘XI’?
  137 |     state = FixState::XIX;
      |                       ^~~
      |                       XI
../fix_eph_gpu.cpp:138:11: error: ‘class LAMMPS_NS::Comm’ has no member named ‘forward_comm_fix’; did you mean ‘forward_comm’?
  138 |     comm->forward_comm_fix(this);
      |           ^~~~~~~~~~~~~~~~
      |           forward_comm
../fix_eph_gpu.cpp:139:23: error: ‘XIY’ is not a member of ‘LAMMPS_NS::FixEPH::FixState’; did you mean ‘XI’?
  139 |     state = FixState::XIY;
      |                       ^~~
      |                       XI
../fix_eph_gpu.cpp:140:11: error: ‘class LAMMPS_NS::Comm’ has no member named ‘forward_comm_fix’; did you mean ‘forward_comm’?
  140 |     comm->forward_comm_fix(this);
      |           ^~~~~~~~~~~~~~~~
      |           forward_comm
../fix_eph_gpu.cpp:141:23: error: ‘XIZ’ is not a member of ‘LAMMPS_NS::FixEPH::FixState’; did you mean ‘XI’?
  141 |     state = FixState::XIZ;
      |                       ^~~
      |                       XI
../fix_eph_gpu.cpp:142:11: error: ‘class LAMMPS_NS::Comm’ has no member named ‘forward_comm_fix’; did you mean ‘forward_comm’?
  142 |     comm->forward_comm_fix(this);
      |           ^~~~~~~~~~~~~~~~
      |           forward_comm
../fix_eph_gpu.cpp:153:9: error: ‘class LAMMPS_NS::Comm’ has no member named ‘forward_comm_fix’; did you mean ‘forward_comm’?
  153 |   comm->forward_comm_fix(this);
      |         ^~~~~~~~~~~~~~~~
      |         forward_comm
../fix_eph_gpu.cpp: In member function ‘void LAMMPS_NS::FixEPHGPU::force_prl()’:
../fix_eph_gpu.cpp:227:21: error: ‘WX’ is not a member of ‘LAMMPS_NS::FixEPH::FixState’; did you mean ‘WI’?
  227 |   state = FixState::WX;
      |                     ^~
      |                     WI
../fix_eph_gpu.cpp:228:9: error: ‘class LAMMPS_NS::Comm’ has no member named ‘forward_comm_fix’; did you mean ‘forward_comm’?
  228 |   comm->forward_comm_fix(this);
      |         ^~~~~~~~~~~~~~~~
      |         forward_comm
../fix_eph_gpu.cpp:229:21: error: ‘WY’ is not a member of ‘LAMMPS_NS::FixEPH::FixState’; did you mean ‘WI’?
  229 |   state = FixState::WY;
      |                     ^~
      |                     WI
../fix_eph_gpu.cpp:230:9: error: ‘class LAMMPS_NS::Comm’ has no member named ‘forward_comm_fix’; did you mean ‘forward_comm’?
  230 |   comm->forward_comm_fix(this);
      |         ^~~~~~~~~~~~~~~~
      |         forward_comm
../fix_eph_gpu.cpp:231:21: error: ‘WZ’ is not a member of ‘LAMMPS_NS::FixEPH::FixState’; did you mean ‘WI’?
  231 |   state = FixState::WZ;
      |                     ^~
      |                     WI
../fix_eph_gpu.cpp:232:9: error: ‘class LAMMPS_NS::Comm’ has no member named ‘forward_comm_fix’; did you mean ‘forward_comm’?
  232 |   comm->forward_comm_fix(this);
      |         ^~~~~~~~~~~~~~~~
      |         forward_comm
make[1]: *** [Makefile:125: fix_eph_gpu.o] Error 1

[artuuuro]

I know what the issue is and it should be quite easily fixable. I changed the logic a bit in the cpu only code and did not verify that gpu is not affected. I will try to solve this as soon as possible.

[Ruoyan0103]

Hi, I encountered the same issue.

[artuuuro]

It would be much more useful if somebody would contribute a KOKKOS version of the fix EPH (rebranding in progress). The approach I took is discouraged by the LAMMPS developers and with KOKKOS it would be possible to target other platforms as well (I doubt it would be as performant as writing native code).

[Mulgish]

I think it is still useful to fix the compilation error in the GPU code.
This code can then be reused in KOKKOS as a next step.