# Note: Currently BOUT++ always needs MPI. This option just determines
# whether the find_* routines are used
option(BOUT_ENABLE_MPI "Enable MPI support" ON)
if(BOUT_ENABLE_MPI)
   # This might not be entirely sensible, but helps CMake to find the
   # correct MPI, workaround for https://gitlab.kitware.com/cmake/cmake/issues/18895
   find_program(MPIEXEC_EXECUTABLE NAMES mpiexec mpirun)
   find_package(MPI REQUIRED)
endif ()
set(BOUT_USE_MPI ${BOUT_ENABLE_MPI})

option(BOUT_ENABLE_OPENMP "Enable OpenMP support" OFF)
set(BOUT_OPENMP_SCHEDULE static CACHE STRING "Set OpenMP schedule")
set_property(CACHE BOUT_OPENMP_SCHEDULE PROPERTY STRINGS static dynamic guided auto)
if (BOUT_ENABLE_OPENMP)
  find_package(OpenMP REQUIRED)
  set(possible_openmp_schedules static dynamic guided auto)
  if (NOT BOUT_OPENMP_SCHEDULE IN_LIST possible_openmp_schedules)
    message(FATAL_ERROR "BOUT_OPENMP_SCHEDULE must be one of ${possible_openmp_schedules}; got ${BOUT_OPENMP_SCHEDULE}")
  endif()
  message(STATUS "OpenMP schedule: ${BOUT_OPENMP_SCHEDULE}")
endif ()
set(BOUT_USE_OPENMP ${BOUT_ENABLE_OPENMP})
message(STATUS "Enable OpenMP: ${BOUT_ENABLE_OPENMP}")

option(BOUT_ENABLE_CUDA "Enable CUDA support" OFF)
set(CUDA_ARCH "compute_70,code=sm_70" CACHE STRING "CUDA architecture")
if(BOUT_ENABLE_CUDA)
   # Set specific options for CUDA if enabled
   enable_language(CUDA)
   set(CMAKE_CUDA_FLAGS "${CMAKE_CUDA_FLAGS} -gencode arch=${CUDA_ARCH} -ccbin ${CMAKE_CXX_COMPILER}")
   if (BOUT_ENABLE_RAJA)
      # RAJA uses lambda expressions
      set(CMAKE_CUDA_FLAGS "${CMAKE_CUDA_FLAGS} --expt-extended-lambda --expt-relaxed-constexpr")
   endif ()

# TODO Ensure openmp flags are not enabled twice!
   if (BOUT_ENABLE_OPENMP)
      # CMAKE_CUDA_FLAGS does not pass OpenMP_CXX_FLAGS to the host compiler by default
      set(CMAKE_CUDA_FLAGS "${CMAKE_CUDA_FLAGS} -Xcompiler ${OpenMP_CXX_FLAGS}")
   endif ()
endif()
set(BOUT_HAS_CUDA ${BOUT_ENABLE_CUDA})