Teuchos_MpiReductionOpSetter.cpp

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00003 // 
00004 //                    Teuchos: Common Tools Package
00005 //                 Copyright (2004) Sandia Corporation
00006 // 
00007 // Under terms of Contract DE-AC04-94AL85000, there is a non-exclusive
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00011 // it under the terms of the GNU Lesser General Public License as
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00020 // You should have received a copy of the GNU Lesser General Public
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00024 // Questions? Contact Michael A. Heroux (maherou@sandia.gov) 
00025 // 
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00027 // @HEADER
00028 
00029 #include "Teuchos_MpiReductionOpSetter.hpp"
00030 #include "Teuchos_OpaqueWrapper.hpp"
00031 #include "Teuchos_GlobalMPISession.hpp"
00032 
00033 //
00034 // This implementation of handling the reduction operator
00035 // will work just fine in a single threaded program.
00036 // For multi-threaded program this has to be reworked!
00037 //
00038 
00039 //
00040 // The callback that an MPI implementation will actually call
00041 //
00042 
00043 extern "C" {
00044 
00045 void Teuchos_MPI_reduction_op(
00046   void              *invec
00047   ,void             *inoutvec
00048   ,int              *len
00049   ,MPI_Datatype     *datatype
00050   );
00051 
00052 void Teuchos_MPI_Op_free( MPI_Op *op )
00053 {
00054   //if(Teuchos::GlobalMPISession::mpiIsInitialized())
00055   //  MPI_Op_free(op);
00056   //else
00057   //  *op = MPI_OP_NULL;
00058   //
00059   // RAB: I have commented this out because this is getting called after
00060   // MPI_Finalize() is called when the Teuchos::GlobalMPISession class is not
00061   // being used..  On some systems, like MPICH, this was not problem.
00062   // However, there are some systems that complain when you do this.
00063   // Therefore, since I don't really know how to fix this problem, I am just
00064   // going to punt and just not delete this MPI_Op object.  I suspect that
00065   // many people do not clean up their MPI objects correctly so I would guess
00066   // that almost every MPI implementation allows you to not free objects and
00067   // end just fine.
00068 }
00069 
00070 } // extern "C"
00071 
00072 //
00073 // Manage the reduction operation as static data.  I have used access
00074 // functions here to allow more insulation for other implementations other
00075 // other than just single threaded programs.
00076 //
00077 
00078 namespace {
00079 
00080 Teuchos::RCP<const Teuchos::MpiReductionOpBase> the_reduct_op = Teuchos::null;
00081 
00082 Teuchos::RCP<const Teuchos::OpaqueWrapper<MPI_Op> > the_mpi_op = Teuchos::null;
00083 
00084 Teuchos::RCP<const Teuchos::MpiReductionOpBase> get_reduct_op()
00085 {
00086   return the_reduct_op;
00087 }
00088 
00089 void set_reduct_op( const Teuchos::RCP<const Teuchos::MpiReductionOpBase>& reduct_op )
00090 {
00091   using Teuchos::null;
00092 #ifdef TEUCHOS_DEBUG
00093   TEST_FOR_EXCEPT( get_reduct_op() != null && reduct_op != null  );
00094 #endif
00095   if(!the_mpi_op.get()) {
00096     MPI_Op mpi_op = MPI_OP_NULL;
00097     TEST_FOR_EXCEPT(
00098       0!=MPI_Op_create( &Teuchos_MPI_reduction_op ,1 ,&mpi_op ) // Assume op is commutative?
00099       );
00100     the_mpi_op = Teuchos::opaqueWrapper(mpi_op,Teuchos_MPI_Op_free);
00101   }
00102   the_reduct_op = reduct_op;
00103 }
00104 
00105 } // namespace
00106 
00107 extern "C" {
00108 
00109 void Teuchos_MPI_reduction_op(
00110   void              *invec
00111   ,void             *inoutvec
00112   ,int              *len
00113   ,MPI_Datatype     *datatype
00114   )
00115 {
00116   get_reduct_op()->reduce(invec,inoutvec,len,datatype);
00117 }
00118 
00119 } // extern "C"
00120 
00121 namespace Teuchos {
00122 
00123 MpiReductionOpSetter::MpiReductionOpSetter(
00124   const Teuchos::RCP<const MpiReductionOpBase>& reduct_op
00125   )
00126 {
00127 #ifdef TEUCHOS_DEBUG
00128   TEST_FOR_EXCEPT(!reduct_op.get())
00129 #endif
00130   set_reduct_op(reduct_op);
00131 }
00132 
00133 MpiReductionOpSetter::~MpiReductionOpSetter()
00134 {
00135   set_reduct_op( null );
00136 }
00137 
00138 MPI_Op MpiReductionOpSetter::mpi_op() const
00139 {
00140   return (*the_mpi_op)();
00141 }
00142 
00143 } // namespace Teuchos

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