Provide the ability to query the communicator from PETSc precondiditioners.

diff --git a/include/deal.II/lac/petsc_precondition.h b/include/deal.II/lac/petsc_precondition.h
index 5304d0b0ec505ede9183ab2a1d5c979bf46e49c0..c5fb9d702d992d071b4fe68a50100d381a820952 100644 (file)
--- a/include/deal.II/lac/petsc_precondition.h
+++ b/include/deal.II/lac/petsc_precondition.h
@@ -62,7 +62,7 @@ namespace PETScWrappers
     /**
      * Constructor.
      */
-    PreconditionBase();
+    PreconditionBase(const MPI_Comm &mpi_communicator = MPI_COMM_NULL);
 
     /**
      * Destructor.
@@ -95,9 +95,20 @@ namespace PETScWrappers
     const PC &
     get_pc() const;
 
+    /**
+     * Return the MPI communicator object used by this preconditioner.
+     */
+    MPI_Comm
+    get_mpi_communicator() const;
+
   protected:
     /**
-     * the PETSc preconditioner object
+     * The communicator to be used for this preconditioner.
+     */
+    MPI_Comm mpi_communicator;
+
+    /**
+     * The PETSc preconditioner object
      */
     PC pc;
 

diff --git a/source/lac/petsc_precondition.cc b/source/lac/petsc_precondition.cc
index eb5e5c80ba27a4d034ac21f3a0d09ba6930d0fb0..6f145d31de4146550c6c4a1ad22256a017dc6754 100644 (file)
--- a/source/lac/petsc_precondition.cc
+++ b/source/lac/petsc_precondition.cc
@@ -33,11 +33,14 @@ DEAL_II_NAMESPACE_OPEN
 
 namespace PETScWrappers
 {
-  PreconditionBase::PreconditionBase()
-    : pc(nullptr)
+  PreconditionBase::PreconditionBase(const MPI_Comm &comm)
+    : mpi_communicator(comm)
+    , pc(nullptr)
     , matrix(nullptr)
   {}
 
+
+
   PreconditionBase::~PreconditionBase()
   {
     try
@@ -48,9 +51,12 @@ namespace PETScWrappers
       {}
   }
 
+
   void
   PreconditionBase::clear()
   {
+    mpi_communicator = MPI_COMM_NULL;
+
     matrix = nullptr;
 
     if (pc != nullptr)
@@ -72,6 +78,7 @@ namespace PETScWrappers
   }
 
 
+
   void
   PreconditionBase::Tvmult(VectorBase &dst, const VectorBase &src) const
   {
@@ -82,6 +89,15 @@ namespace PETScWrappers
   }
 
 
+
+  MPI_Comm
+  PreconditionBase::get_mpi_communicator() const
+  {
+    return mpi_communicator;
+  }
+
+
+
   void
   PreconditionBase::create_pc()
   {
@@ -89,15 +105,9 @@ namespace PETScWrappers
     // preconditioner once
     AssertThrow(pc == nullptr, StandardExceptions::ExcInvalidState());
 
-    MPI_Comm comm;
-    // this ugly cast is necessary because the
-    // type Mat and PETScObject are
-    // unrelated.
-    PetscErrorCode ierr =
-      PetscObjectGetComm(reinterpret_cast<PetscObject>(matrix), &comm);
-    AssertThrow(ierr == 0, ExcPETScError(ierr));
+    MPI_Comm comm = get_mpi_communicator();
 
-    ierr = PCCreate(comm, &pc);
+    PetscErrorCode ierr = PCCreate(comm, &pc);
     AssertThrow(ierr == 0, ExcPETScError(ierr));
 
 #  if DEAL_II_PETSC_VERSION_LT(3, 5, 0)
@@ -125,6 +135,7 @@ namespace PETScWrappers
   /* ----------------- PreconditionJacobi -------------------- */
   PreconditionJacobi::PreconditionJacobi(const MPI_Comm &      comm,
                                          const AdditionalData &additional_data_)
+    : PreconditionBase(comm)
   {
     additional_data = additional_data_;
 
@@ -138,10 +149,13 @@ namespace PETScWrappers
 
   PreconditionJacobi::PreconditionJacobi(const MatrixBase &    matrix,
                                          const AdditionalData &additional_data)
+    : PreconditionBase(matrix.get_mpi_communicator())
   {
     initialize(matrix, additional_data);
   }
 
+
+
   void
   PreconditionJacobi::initialize()
   {
@@ -154,12 +168,16 @@ namespace PETScWrappers
     AssertThrow(ierr == 0, ExcPETScError(ierr));
   }
 
+
+
   void
   PreconditionJacobi::initialize(const MatrixBase &    matrix_,
                                  const AdditionalData &additional_data_)
   {
     clear();
 
+    mpi_communicator = matrix_.get_mpi_communicator();
+
     matrix          = static_cast<Mat>(matrix_);
     additional_data = additional_data_;
 
@@ -172,9 +190,12 @@ namespace PETScWrappers
 
 
   /* ----------------- PreconditionBlockJacobi -------------------- */
+
+
   PreconditionBlockJacobi::PreconditionBlockJacobi(
     const MPI_Comm &      comm,
     const AdditionalData &additional_data_)
+    : PreconditionBase(comm)
   {
     additional_data = additional_data_;
 
@@ -189,10 +210,13 @@ namespace PETScWrappers
   PreconditionBlockJacobi::PreconditionBlockJacobi(
     const MatrixBase &    matrix,
     const AdditionalData &additional_data)
+    : PreconditionBase(matrix.get_mpi_communicator())
   {
     initialize(matrix, additional_data);
   }
 
+
+
   void
   PreconditionBlockJacobi::initialize()
   {
@@ -204,12 +228,15 @@ namespace PETScWrappers
   }
 
 
+
   void
   PreconditionBlockJacobi::initialize(const MatrixBase &    matrix_,
                                       const AdditionalData &additional_data_)
   {
     clear();
 
+    mpi_communicator = matrix_.get_mpi_communicator();
+
     matrix          = static_cast<Mat>(matrix_);
     additional_data = additional_data_;
 
@@ -231,6 +258,7 @@ namespace PETScWrappers
 
   PreconditionSOR::PreconditionSOR(const MatrixBase &    matrix,
                                    const AdditionalData &additional_data)
+    : PreconditionBase(matrix.get_mpi_communicator())
   {
     initialize(matrix, additional_data);
   }
@@ -242,6 +270,8 @@ namespace PETScWrappers
   {
     clear();
 
+    mpi_communicator = matrix_.get_mpi_communicator();
+
     matrix          = static_cast<Mat>(matrix_);
     additional_data = additional_data_;
 
@@ -272,6 +302,7 @@ namespace PETScWrappers
 
   PreconditionSSOR::PreconditionSSOR(const MatrixBase &    matrix,
                                      const AdditionalData &additional_data)
+    : PreconditionBase(matrix.get_mpi_communicator())
   {
     initialize(matrix, additional_data);
   }
@@ -283,6 +314,8 @@ namespace PETScWrappers
   {
     clear();
 
+    mpi_communicator = matrix_.get_mpi_communicator();
+
     matrix          = static_cast<Mat>(matrix_);
     additional_data = additional_data_;
 
@@ -318,6 +351,7 @@ namespace PETScWrappers
 
   PreconditionICC::PreconditionICC(const MatrixBase &    matrix,
                                    const AdditionalData &additional_data)
+    : PreconditionBase(matrix.get_mpi_communicator())
   {
     initialize(matrix, additional_data);
   }
@@ -329,6 +363,8 @@ namespace PETScWrappers
   {
     clear();
 
+    mpi_communicator = matrix_.get_mpi_communicator();
+
     matrix          = static_cast<Mat>(matrix_);
     additional_data = additional_data_;
 
@@ -359,6 +395,7 @@ namespace PETScWrappers
 
   PreconditionILU::PreconditionILU(const MatrixBase &    matrix,
                                    const AdditionalData &additional_data)
+    : PreconditionBase(matrix.get_mpi_communicator())
   {
     initialize(matrix, additional_data);
   }
@@ -370,6 +407,8 @@ namespace PETScWrappers
   {
     clear();
 
+    mpi_communicator = matrix_.get_mpi_communicator();
+
     matrix          = static_cast<Mat>(matrix_);
     additional_data = additional_data_;
 
@@ -501,6 +540,7 @@ namespace PETScWrappers
   PreconditionBoomerAMG::PreconditionBoomerAMG(
     const MPI_Comm &      comm,
     const AdditionalData &additional_data_)
+    : PreconditionBase(comm)
   {
     additional_data = additional_data_;
 
@@ -518,13 +558,17 @@ namespace PETScWrappers
   }
 
 
+
   PreconditionBoomerAMG::PreconditionBoomerAMG(
     const MatrixBase &    matrix,
     const AdditionalData &additional_data)
+    : PreconditionBase(matrix.get_mpi_communicator())
   {
     initialize(matrix, additional_data);
   }
 
+
+
   void
   PreconditionBoomerAMG::initialize()
   {
@@ -633,6 +677,8 @@ namespace PETScWrappers
 #  endif
   }
 
+
+
   void
   PreconditionBoomerAMG::initialize(const MatrixBase &    matrix_,
                                     const AdditionalData &additional_data_)
@@ -640,6 +686,8 @@ namespace PETScWrappers
 #  ifdef DEAL_II_PETSC_WITH_HYPRE
     clear();
 
+    mpi_communicator = matrix_.get_mpi_communicator();
+
     matrix          = static_cast<Mat>(matrix_);
     additional_data = additional_data_;
 
@@ -679,6 +727,7 @@ namespace PETScWrappers
   PreconditionParaSails::PreconditionParaSails(
     const MatrixBase &    matrix,
     const AdditionalData &additional_data)
+    : PreconditionBase(matrix.get_mpi_communicator())
   {
     initialize(matrix, additional_data);
   }
@@ -690,6 +739,8 @@ namespace PETScWrappers
   {
     clear();
 
+    mpi_communicator = matrix_.get_mpi_communicator();
+
     matrix          = static_cast<Mat>(matrix_);
     additional_data = additional_data_;
 
@@ -773,6 +824,7 @@ namespace PETScWrappers
 
   PreconditionNone::PreconditionNone(const MatrixBase &    matrix,
                                      const AdditionalData &additional_data)
+    : PreconditionBase(matrix.get_mpi_communicator())
   {
     initialize(matrix, additional_data);
   }
@@ -784,6 +836,8 @@ namespace PETScWrappers
   {
     clear();
 
+    mpi_communicator = matrix_.get_mpi_communicator();
+
     matrix          = static_cast<Mat>(matrix_);
     additional_data = additional_data_;
 
@@ -814,6 +868,7 @@ namespace PETScWrappers
 
   PreconditionLU::PreconditionLU(const MatrixBase &    matrix,
                                  const AdditionalData &additional_data)
+    : PreconditionBase(matrix.get_mpi_communicator())
   {
     initialize(matrix, additional_data);
   }
@@ -825,6 +880,8 @@ namespace PETScWrappers
   {
     clear();
 
+    mpi_communicator = matrix_.get_mpi_communicator();
+
     matrix          = static_cast<Mat>(matrix_);
     additional_data = additional_data_;
 
@@ -866,10 +923,13 @@ namespace PETScWrappers
     , coords(coords)
   {}
 
+
+
   template <int dim>
   PreconditionBDDC<dim>::PreconditionBDDC(
     const MPI_Comm        comm,
     const AdditionalData &additional_data_)
+    : PreconditionBase(comm)
   {
     additional_data = additional_data_;
 
@@ -879,14 +939,18 @@ namespace PETScWrappers
     initialize();
   }
 
+
+
   template <int dim>
   PreconditionBDDC<dim>::PreconditionBDDC(const MatrixBase &    matrix,
                                           const AdditionalData &additional_data)
+    : PreconditionBase(matrix.get_mpi_communicator())
   {
     initialize(matrix, additional_data);
   }
 
 
+
   template <int dim>
   void
   PreconditionBDDC<dim>::initialize()
@@ -960,6 +1024,8 @@ namespace PETScWrappers
 #  endif
   }
 
+
+
   template <int dim>
   void
   PreconditionBDDC<dim>::initialize(const MatrixBase &    matrix_,
@@ -967,6 +1033,8 @@ namespace PETScWrappers
   {
     clear();
 
+    mpi_communicator = matrix_.get_mpi_communicator();
+
     matrix          = static_cast<Mat>(matrix_);
     additional_data = additional_data_;