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# Manage the OpenMP setup. This wrapper file checks for some known-bad compiler
# versions before trying to detect OpenMP with the standard find-package-module,
# and then does some additional tests for flags afterwards.

if(GMX_OPENMP)
    # We should do OpenMP detection if we get here
    # OpenMP check must come before other CFLAGS!
    find_package(OpenMP)
    if(NOT OPENMP_FOUND)
        if(CMAKE_CXX_COMPILER MATCHES "dpcpp")
            message(WARNING "The Intel dpcpp compiler does not support OpenMP; consider using the icx (C) & icpx (C++) compilers from the Intel HPC toolkit instead. For now, we are turning off OpenMP.")
        else()
            message(WARNING "The compiler you are using does not support OpenMP parallelism. This might hurt your performance a lot, in particular with GPUs. Try using a more recent version, or a different compiler. For now, we are proceeding by turning off OpenMP.")
        endif()
        set(GMX_OPENMP OFF CACHE STRING "Whether GROMACS will use OpenMP parallelism." FORCE)
    endif()
endif()
gmx_dependent_cache_variable(GMX_OPENMP_MAX_THREADS
    "Maximum number of OpenMP Threads supported. Has to be 32 or a multiple of 64."
    STRING 128 GMX_OPENMP)
mark_as_advanced(GMX_OPENMP_MAX_THREADS)
math(EXPR MAX_THREAD_MOD "${GMX_OPENMP_MAX_THREADS} % 64")
if (NOT GMX_OPENMP_MAX_THREADS EQUAL 32 AND NOT ${MAX_THREAD_MOD} EQUAL 0)
    message(FATAL_ERROR "Only 32 or multiples of 64 supported for GMX_OPENMP_MAX_THREADS.")
endif()
