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37 * Implements functions from init.h.
39 * \author Teemu Murtola <teemu.murtola@gmail.com>
40 * \ingroup module_utility
42 #include "gromacs/utility/init.h"
48 #include "gromacs/legacyheaders/gmx_fatal.h"
51 #include "gromacs/utility/gmxmpi.h"
54 #include "gromacs/utility/common.h"
55 #include "gromacs/utility/gmxassert.h"
63 //! Maintains global counter of attempts to initialize MPI
64 int g_initializationCounter = 0;
68 void init(int *argc, char ***argv)
71 int isInitialized = 0, isFinalized = 0;
72 MPI_Finalized(&isFinalized);
73 GMX_RELEASE_ASSERT(!isFinalized, "Invalid attempt to initialize MPI after finalization");
74 MPI_Initialized(&isInitialized);
77 if (0 == g_initializationCounter)
79 // Some other code has already initialized MPI, so bump the counter so that
80 // we know not to finalize MPI ourselves later.
81 g_initializationCounter++;
87 fah_MPI_Init(argc, argv);
90 /* Formally we need to use MPI_Init_thread and ask for MPI_THREAD_FUNNELED
91 * level of thread support when using OpenMP. However, in practice we
92 * have never seen any problems with just using MPI_Init(), and some MPI
93 * versions that only return MPI_THREAD_SINGLE as their support level
94 * still return an OK initialization code when we request MPI_THREAD_FUNNELED.
96 * To avoid requiring users to recompile and install new libraries for something
97 * that probably isn't a problem, we don't make a fuss about it (no warning)
98 * if MPI_Init_thread() returns ok. If it does not return OK we
99 * call a second init call without thread support, but since the library
100 * apparently tried to prevent this we do issue a warning in this case.
102 * support, and if that doesn't work we simply use the simple MPI_Init().
103 * Note that MPICH does not allow us to call MPI_Query_thread() before
104 * we have initialized the library, and calling MPI_Init twice could
105 * be a bit fragile. However, some implementations also advice against
106 * doing anything else after calling MPI_Finalize, so at the end of the
107 * day we'll have to cross our fingers...
110 rc = MPI_Init_thread(argc, argv, MPI_THREAD_FUNNELED, &provided);
111 if (rc != 0 && provided < MPI_THREAD_FUNNELED)
113 gmx_warning("GROMACS was compiled with OpenMP support, but there is no thread support in the MPI library. Keep your fingers crossed.");
114 MPI_Init(argc, argv);
117 MPI_Init(argc, argv);
121 // Bump the counter to record this initialization event
122 g_initializationCounter++;
125 GMX_UNUSED_VALUE(argc);
126 GMX_UNUSED_VALUE(argv);
133 GMX_RELEASE_ASSERT(0 < g_initializationCounter, "Excess attempt to finalize MPI");
134 // Bump the counter to record this finalization event
135 g_initializationCounter--;
137 if (0 == g_initializationCounter)
139 /* We sync the processes here to try to avoid problems
140 * with buggy MPI implementations that could cause
141 * unfinished processes to terminate.
143 MPI_Barrier(MPI_COMM_WORLD);
145 /* Apparently certain mpich implementations cause problems
146 * with MPI_Finalize. In that case comment out MPI_Finalize.