#include <partitioner.h>

Inheritance diagram for libMesh::Partitioner:

Public Member Functions
	Partitioner ()
virtual	~Partitioner ()
virtual UniquePtr< Partitioner >	clone () const =0
void	partition (MeshBase &mesh, const unsigned int n)
void	partition (MeshBase &mesh)
void	repartition (MeshBase &mesh, const unsigned int n)
void	repartition (MeshBase &mesh)
virtual void	attach_weights (ErrorVector *)
Static Public Member Functions
static void	partition_unpartitioned_elements (MeshBase &mesh)
static void	partition_unpartitioned_elements (MeshBase &mesh, const unsigned int n)
static void	set_parent_processor_ids (MeshBase &mesh)
static void	set_node_processor_ids (MeshBase &mesh)
Protected Member Functions
void	single_partition (MeshBase &mesh)
virtual void	_do_partition (MeshBase &mesh, const unsigned int n)=0
virtual void	_do_repartition (MeshBase &mesh, const unsigned int n)
Protected Attributes
ErrorVector *	_weights
Static Protected Attributes
static const dof_id_type	communication_blocksize = 1000000

Detailed Description

The Partitioner class provides a uniform interface for partitioning algorithms. It takes a reference to a MeshBase object as input, which it will partition into a number of subdomains.

Definition at line 48 of file partitioner.h.

Constructor & Destructor Documentation

libMesh::Partitioner::Partitioner ( ) [inline]

Constructor.

Definition at line 55 of file partitioner.h.

:_weights(NULL) {}

virtual libMesh::Partitioner::~Partitioner ( ) [inline, virtual]

Destructor. Virtual so that we can derive from this class.

Definition at line 60 of file partitioner.h.

{}

Member Function Documentation

virtual void libMesh::Partitioner::_do_partition	(	MeshBase &	mesh,
		const unsigned int	n
	)		`[protected, pure virtual]`

This is the actual partitioning method which must be overloaded in derived classes. It is called via the public partition() method above by the user.

Implemented in libMesh::CentroidPartitioner, libMesh::ParmetisPartitioner, libMesh::SFCPartitioner, libMesh::HilbertSFCPartitioner, libMesh::MetisPartitioner, libMesh::MortonSFCPartitioner, and libMesh::LinearPartitioner.

Referenced by _do_repartition(), and partition().

virtual void libMesh::Partitioner::_do_repartition	(	MeshBase &	mesh,
		const unsigned int	n
	)		`[inline, protected, virtual]`

This is the actual re-partitioning method which can be overloaded in derived classes. Note that the default behavior is to simply call the partition function.

Reimplemented in libMesh::ParmetisPartitioner.

Definition at line 156 of file partitioner.h.

References _do_partition().

Referenced by repartition().

                                                      { this->_do_partition (mesh, n); }

virtual void libMesh::Partitioner::attach_weights ( ErrorVector * ) [inline, virtual]

Attach weights that can be used for partitioning. This ErrorVector should be _exactly_ the same on every processor and should have mesh->max_elem_id() entries.

Reimplemented in libMesh::MetisPartitioner.

Definition at line 131 of file partitioner.h.

{ libmesh_not_implemented(); }

virtual UniquePtr<Partitioner> libMesh::Partitioner::clone ( ) const [pure virtual]

Creates a new partitioner of this type and returns it in an UniquePtr. This is used when copying meshes, and must be overloaded in the derived classes.

Implemented in libMesh::CentroidPartitioner, libMesh::ParmetisPartitioner, libMesh::SFCPartitioner, libMesh::HilbertSFCPartitioner, libMesh::MortonSFCPartitioner, libMesh::LinearPartitioner, and libMesh::MetisPartitioner.

void libMesh::Partitioner::partition	(	MeshBase &	mesh,
		const unsigned int	n
	)

Partition the MeshBase into n parts. The partitioner currently does not modify the subdomain_id of each element. This number is reserved for things like material properties, etc.

Definition at line 55 of file partitioner.C.

References _do_partition(), libMesh::ParallelObject::comm(), libMesh::MeshTools::libmesh_assert_valid_procids< Elem >(), libMesh::MeshTools::libmesh_assert_valid_remote_elems(), mesh, std::min(), libMesh::MeshBase::n_active_elem(), partition_unpartitioned_elements(), libMesh::MeshBase::redistribute(), libMesh::MeshBase::set_n_partitions(), set_node_processor_ids(), set_parent_processor_ids(), single_partition(), and libMesh::MeshBase::update_post_partitioning().

Referenced by libMesh::MetisPartitioner::_do_partition(), libMesh::SFCPartitioner::_do_partition(), libMesh::ParmetisPartitioner::_do_repartition(), and partition().

{
  libmesh_parallel_only(mesh.comm());

  // BSK - temporary fix while redistribution is integrated 6/26/2008
  // Uncomment this to not repartition in parallel
  //   if (!mesh.is_serial())
  //     return;

  // we cannot partition into more pieces than we have
  // active elements!
  const unsigned int n_parts =
    static_cast<unsigned int>
    (std::min(mesh.n_active_elem(), static_cast<dof_id_type>(n)));

  // Set the number of partitions in the mesh
  mesh.set_n_partitions()=n_parts;

  if (n_parts == 1)
    {
      this->single_partition (mesh);
      return;
    }

  // First assign a temporary partitioning to any unpartitioned elements
  Partitioner::partition_unpartitioned_elements(mesh, n_parts);

  // Call the partitioning function
  this->_do_partition(mesh,n_parts);

  // Set the parent's processor ids
  Partitioner::set_parent_processor_ids(mesh);

  // Redistribute elements if necessary, before setting node processor
  // ids, to make sure those will be set consistently
  mesh.redistribute();

#ifdef DEBUG
  MeshTools::libmesh_assert_valid_remote_elems(mesh);

  // Messed up elem processor_id()s can leave us without the child
  // elements we need to restrict vectors on a distributed mesh
  MeshTools::libmesh_assert_valid_procids<Elem>(mesh);
#endif

  // Set the node's processor ids
  Partitioner::set_node_processor_ids(mesh);

#ifdef DEBUG
  MeshTools::libmesh_assert_valid_procids<Elem>(mesh);
#endif

  // Give derived Mesh classes a chance to update any cached data to
  // reflect the new partitioning
  mesh.update_post_partitioning();
}

void libMesh::Partitioner::partition ( MeshBase & mesh )

Partition the MeshBase into mesh.n_processors() parts. The partitioner currently does not modify the subdomain_id of each element. This number is reserved for things like material properties, etc.

Definition at line 48 of file partitioner.C.

References libMesh::ParallelObject::n_processors(), and partition().

{
  this->partition(mesh,mesh.n_processors());
}

void libMesh::Partitioner::partition_unpartitioned_elements ( MeshBase & mesh ) [static]

This function

Definition at line 180 of file partitioner.C.

References libMesh::ParallelObject::n_processors().

Referenced by partition(), and repartition().

{
  Partitioner::partition_unpartitioned_elements(mesh, mesh.n_processors());
}

void libMesh::Partitioner::partition_unpartitioned_elements	(	MeshBase &	mesh,
		const unsigned int	n
	)		`[static]`

Definition at line 187 of file partitioner.C.

References libMesh::MeshTools::bounding_box(), libMesh::ParallelObject::comm(), end, libMesh::MeshCommunication::find_global_indices(), libMesh::MeshTools::n_elem(), libMesh::ParallelObject::n_processors(), libMesh::DofObject::processor_id(), libMesh::MeshBase::unpartitioned_elements_begin(), and libMesh::MeshBase::unpartitioned_elements_end().

{
  MeshBase::element_iterator       it  = mesh.unpartitioned_elements_begin();
  const MeshBase::element_iterator end = mesh.unpartitioned_elements_end();

  const dof_id_type n_unpartitioned_elements = MeshTools::n_elem (it, end);

  // the unpartitioned elements must exist on all processors. If the range is empty on one
  // it is empty on all, and we can quit right here.
  if (!n_unpartitioned_elements) return;

  // find the target subdomain sizes
  std::vector<dof_id_type> subdomain_bounds(mesh.n_processors());

  for (processor_id_type pid=0; pid<mesh.n_processors(); pid++)
    {
      dof_id_type tgt_subdomain_size = 0;

      // watch out for the case that n_subdomains < n_processors
      if (pid < n_subdomains)
        {
          tgt_subdomain_size = n_unpartitioned_elements/n_subdomains;

          if (pid < n_unpartitioned_elements%n_subdomains)
            tgt_subdomain_size++;

        }

      //libMesh::out << "pid, #= " << pid << ", " << tgt_subdomain_size << std::endl;
      if (pid == 0)
        subdomain_bounds[0] = tgt_subdomain_size;
      else
        subdomain_bounds[pid] = subdomain_bounds[pid-1] + tgt_subdomain_size;
    }

  libmesh_assert_equal_to (subdomain_bounds.back(), n_unpartitioned_elements);

  // create the unique mapping for all unpartitioned elements independent of partitioning
  // determine the global indexing for all the unpartitoned elements
  std::vector<dof_id_type> global_indices;

  // Calling this on all processors a unique range in [0,n_unpartitioned_elements) is constructed.
  // Only the indices for the elements we pass in are returned in the array.
  MeshCommunication().find_global_indices (mesh.comm(),
                                           MeshTools::bounding_box(mesh), it, end,
                                           global_indices);

  for (dof_id_type cnt=0; it != end; ++it)
    {
      Elem *elem = *it;

      libmesh_assert_less (cnt, global_indices.size());
      const dof_id_type global_index =
        global_indices[cnt++];

      libmesh_assert_less (global_index, subdomain_bounds.back());
      libmesh_assert_less (global_index, n_unpartitioned_elements);

      const processor_id_type subdomain_id =
        cast_int<processor_id_type>
        (std::distance(subdomain_bounds.begin(),
                       std::upper_bound(subdomain_bounds.begin(),
                                        subdomain_bounds.end(),
                                        global_index)));
      libmesh_assert_less (subdomain_id, n_subdomains);

      elem->processor_id() = subdomain_id;
      //libMesh::out << "assigning " << global_index << " to " << subdomain_id << std::endl;
    }
}

void libMesh::Partitioner::repartition	(	MeshBase &	mesh,
		const unsigned int	n
	)

Repartitions the MeshBase into n parts. This is required since some partitoning algorithms can repartition more efficiently than computing a new partitioning from scratch. The default behavior is to simply call this->partition(mesh,n)

Definition at line 122 of file partitioner.C.

References _do_repartition(), std::min(), libMesh::MeshBase::n_active_elem(), partition_unpartitioned_elements(), libMesh::MeshBase::set_n_partitions(), set_node_processor_ids(), set_parent_processor_ids(), and single_partition().

Referenced by repartition().

{
  // we cannot partition into more pieces than we have
  // active elements!
  const unsigned int n_parts =
    static_cast<unsigned int>
    (std::min(mesh.n_active_elem(), static_cast<dof_id_type>(n)));

  // Set the number of partitions in the mesh
  mesh.set_n_partitions()=n_parts;

  if (n_parts == 1)
    {
      this->single_partition (mesh);
      return;
    }

  // First assign a temporary partitioning to any unpartitioned elements
  Partitioner::partition_unpartitioned_elements(mesh, n_parts);

  // Call the partitioning function
  this->_do_repartition(mesh,n_parts);

  // Set the parent's processor ids
  Partitioner::set_parent_processor_ids(mesh);

  // Set the node's processor ids
  Partitioner::set_node_processor_ids(mesh);
}

void libMesh::Partitioner::repartition ( MeshBase & mesh )

Repartitions the MeshBase into mesh.n_processors() parts. This is required since some partitoning algorithms can repartition more efficiently than computing a new partitioning from scratch.

Definition at line 115 of file partitioner.C.

References libMesh::ParallelObject::n_processors(), and repartition().

{
  this->repartition(mesh,mesh.n_processors());
}

void libMesh::Partitioner::set_node_processor_ids ( MeshBase & mesh ) [static]

This function is called after partitioning to set the processor IDs for the nodes. By definition, a Node's processor ID is the minimum processor ID for all of the elements which share the node.

Definition at line 439 of file partitioner.C.

Referenced by libMesh::UnstructuredMesh::all_first_order(), partition(), libMesh::MeshBase::partition(), libMesh::XdrIO::read(), repartition(), and libMesh::BoundaryInfo::sync().

{
  START_LOG("set_node_processor_ids()","Partitioner");

  // This function must be run on all processors at once
  libmesh_parallel_only(mesh.comm());

  // If we have any unpartitioned elements at this
  // stage there is a problem
  libmesh_assert (MeshTools::n_elem(mesh.unpartitioned_elements_begin(),
                                    mesh.unpartitioned_elements_end()) == 0);


  //   const dof_id_type orig_n_local_nodes = mesh.n_local_nodes();

  //   libMesh::err << "[" << mesh.processor_id() << "]: orig_n_local_nodes="
  //     << orig_n_local_nodes << std::endl;

  // Build up request sets.  Each node is currently owned by a processor because
  // it is connected to an element owned by that processor.  However, during the
  // repartitioning phase that element may have been assigned a new processor id, but
  // it is still resident on the original processor.  We need to know where to look
  // for new ids before assigning new ids, otherwise we may be asking the wrong processors
  // for the wrong information.
  //
  // The only remaining issue is what to do with unpartitioned nodes.  Since they are required
  // to live on all processors we can simply rely on ourselves to number them properly.
  std::vector<std::vector<dof_id_type> >
    requested_node_ids(mesh.n_processors());

  // Loop over all the nodes, count the ones on each processor.  We can skip ourself
  std::vector<dof_id_type> ghost_nodes_from_proc(mesh.n_processors(), 0);

  MeshBase::node_iterator       node_it  = mesh.nodes_begin();
  const MeshBase::node_iterator node_end = mesh.nodes_end();

  for (; node_it != node_end; ++node_it)
    {
      Node *node = *node_it;
      libmesh_assert(node);
      const processor_id_type current_pid = node->processor_id();
      if (current_pid != mesh.processor_id() &&
          current_pid != DofObject::invalid_processor_id)
        {
          libmesh_assert_less (current_pid, ghost_nodes_from_proc.size());
          ghost_nodes_from_proc[current_pid]++;
        }
    }

  // We know how many objects live on each processor, so reserve()
  // space for each.
  for (processor_id_type pid=0; pid != mesh.n_processors(); ++pid)
    requested_node_ids[pid].reserve(ghost_nodes_from_proc[pid]);

  // We need to get the new pid for each node from the processor
  // which *currently* owns the node.  We can safely skip ourself
  for (node_it = mesh.nodes_begin(); node_it != node_end; ++node_it)
    {
      Node *node = *node_it;
      libmesh_assert(node);
      const processor_id_type current_pid = node->processor_id();
      if (current_pid != mesh.processor_id() &&
          current_pid != DofObject::invalid_processor_id)
        {
          libmesh_assert_less (current_pid, requested_node_ids.size());
          libmesh_assert_less (requested_node_ids[current_pid].size(),
                               ghost_nodes_from_proc[current_pid]);
          requested_node_ids[current_pid].push_back(node->id());
        }

      // Unset any previously-set node processor ids
      node->invalidate_processor_id();
    }

  // Loop over all the active elements
  MeshBase::element_iterator       elem_it  = mesh.active_elements_begin();
  const MeshBase::element_iterator elem_end = mesh.active_elements_end();

  for ( ; elem_it != elem_end; ++elem_it)
    {
      Elem* elem = *elem_it;
      libmesh_assert(elem);

      libmesh_assert_not_equal_to (elem->processor_id(), DofObject::invalid_processor_id);

      // For each node, set the processor ID to the min of
      // its current value and this Element's processor id.
      //
      // TODO: we would probably get better parallel partitioning if
      // we did something like "min for even numbered nodes, max for
      // odd numbered".  We'd need to be careful about how that would
      // affect solution ordering for I/O, though.
      for (unsigned int n=0; n<elem->n_nodes(); ++n)
        elem->get_node(n)->processor_id() = std::min(elem->get_node(n)->processor_id(),
                                                     elem->processor_id());
    }

  // And loop over the subactive elements, but don't reassign
  // nodes that are already active on another processor.
  MeshBase::element_iterator       sub_it  = mesh.subactive_elements_begin();
  const MeshBase::element_iterator sub_end = mesh.subactive_elements_end();

  for ( ; sub_it != sub_end; ++sub_it)
    {
      Elem* elem = *sub_it;
      libmesh_assert(elem);

      libmesh_assert_not_equal_to (elem->processor_id(), DofObject::invalid_processor_id);

      for (unsigned int n=0; n<elem->n_nodes(); ++n)
        if (elem->get_node(n)->processor_id() == DofObject::invalid_processor_id)
          elem->get_node(n)->processor_id() = elem->processor_id();
    }

  // Same for the inactive elements -- we will have already gotten most of these
  // nodes, *except* for the case of a parent with a subset of children which are
  // ghost elements.  In that case some of the parent nodes will not have been
  // properly handled yet
  MeshBase::element_iterator       not_it  = mesh.not_active_elements_begin();
  const MeshBase::element_iterator not_end = mesh.not_active_elements_end();

  for ( ; not_it != not_end; ++not_it)
    {
      Elem* elem = *not_it;
      libmesh_assert(elem);

      libmesh_assert_not_equal_to (elem->processor_id(), DofObject::invalid_processor_id);

      for (unsigned int n=0; n<elem->n_nodes(); ++n)
        if (elem->get_node(n)->processor_id() == DofObject::invalid_processor_id)
          elem->get_node(n)->processor_id() = elem->processor_id();
    }

  // We can't assert that all nodes are connected to elements, because
  // a ParallelMesh with NodeConstraints might have pulled in some
  // remote nodes solely for evaluating those constraints.
  // MeshTools::libmesh_assert_connected_nodes(mesh);

  // For such nodes, we'll do a sanity check later when making sure
  // that we successfully reset their processor ids to something
  // valid.

  // Next set node ids from other processors, excluding self
  for (processor_id_type p=1; p != mesh.n_processors(); ++p)
    {
      // Trade my requests with processor procup and procdown
      processor_id_type procup = cast_int<processor_id_type>
        ((mesh.processor_id() + p) % mesh.n_processors());
      processor_id_type procdown = cast_int<processor_id_type>
        ((mesh.n_processors() + mesh.processor_id() - p) %
         mesh.n_processors());
      std::vector<dof_id_type> request_to_fill;
      mesh.comm().send_receive(procup, requested_node_ids[procup],
                               procdown, request_to_fill);

      // Fill those requests in-place
      for (std::size_t i=0; i != request_to_fill.size(); ++i)
        {
          Node *node = mesh.node_ptr(request_to_fill[i]);
          libmesh_assert(node);
          const processor_id_type new_pid = node->processor_id();

// We may have an invalid processor_id() on nodes that have been
// "detatched" from coarsened-away elements but that have not yet
// themselves been removed.
//          libmesh_assert_not_equal_to (new_pid, DofObject::invalid_processor_id);
//          libmesh_assert_less (new_pid, mesh.n_partitions()); // this is the correct test --

          request_to_fill[i] = new_pid;           //  the number of partitions may
        }                                         //  not equal the number of processors

      // Trade back the results
      std::vector<dof_id_type> filled_request;
      mesh.comm().send_receive(procdown, request_to_fill,
                               procup,   filled_request);
      libmesh_assert_equal_to (filled_request.size(), requested_node_ids[procup].size());

      // And copy the id changes we've now been informed of
      for (std::size_t i=0; i != filled_request.size(); ++i)
        {
          Node *node = mesh.node_ptr(requested_node_ids[procup][i]);
          libmesh_assert(node);

          // this is the correct test -- the number of partitions may
          // not equal the number of processors

          // But: we may have an invalid processor_id() on nodes that
          // have been "detatched" from coarsened-away elements but
          // that have not yet themselves been removed.
          // libmesh_assert_less (filled_request[i], mesh.n_partitions());

          node->processor_id(cast_int<processor_id_type>(filled_request[i]));
        }
    }

#ifdef DEBUG
  MeshTools::libmesh_assert_valid_procids<Node>(mesh);
#endif

  STOP_LOG("set_node_processor_ids()","Partitioner");
}

void libMesh::Partitioner::set_parent_processor_ids ( MeshBase & mesh ) [static]

This function is called after partitioning to set the processor IDs for the inactive parent elements. A Parent's processor ID is the same as its first child.

Definition at line 261 of file partitioner.C.

References libMesh::Elem::active_family_tree(), libMesh::Elem::child(), communication_blocksize, end, libMesh::DofObject::id(), libMesh::DofObject::invalid_processor_id, libMesh::DofObject::invalidate_processor_id(), libMesh::Elem::is_remote(), libMesh::libmesh_assert(), mesh, std::min(), libMesh::Elem::n_children(), libMesh::MeshTools::n_elem(), libMesh::Elem::parent(), libMesh::processor_id(), libMesh::DofObject::processor_id(), libMesh::START_LOG(), and libMesh::Elem::total_family_tree().

Referenced by partition(), and repartition().

{
  START_LOG("set_parent_processor_ids()","Partitioner");

#ifdef LIBMESH_ENABLE_AMR

  // If the mesh is serial we have access to all the elements,
  // in particular all the active ones.  We can therefore set
  // the parent processor ids indirecly through their children, and
  // set the subactive processor ids while examining their active
  // ancestors.
  // By convention a parent is assigned to the minimum processor
  // of all its children, and a subactive is assigned to the processor
  // of its active ancestor.
  if (mesh.is_serial())
    {
      // Loop over all the active elements in the mesh
      MeshBase::element_iterator       it  = mesh.active_elements_begin();
      const MeshBase::element_iterator end = mesh.active_elements_end();

      for ( ; it!=end; ++it)
        {
          Elem *child  = *it;

          // First set descendents

          std::vector<const Elem*> subactive_family;
          child->total_family_tree(subactive_family);
          for (unsigned int i = 0; i != subactive_family.size(); ++i)
            const_cast<Elem*>(subactive_family[i])->processor_id() = child->processor_id();

          // Then set ancestors

          Elem *parent = child->parent();

          while (parent)
            {
              // invalidate the parent id, otherwise the min below
              // will not work if the current parent id is less
              // than all the children!
              parent->invalidate_processor_id();

              for(unsigned int c=0; c<parent->n_children(); c++)
                {
                  child = parent->child(c);
                  libmesh_assert(child);
                  libmesh_assert(!child->is_remote());
                  libmesh_assert_not_equal_to (child->processor_id(), DofObject::invalid_processor_id);
                  parent->processor_id() = std::min(parent->processor_id(),
                                                    child->processor_id());
                }
              parent = parent->parent();
            }
        }
    }

  // When the mesh is parallel we cannot guarantee that parents have access to
  // all their children.
  else
    {
      // Setting subactive processor ids is easy: we can guarantee
      // that children have access to all their parents.

      // Loop over all the active elements in the mesh
      MeshBase::element_iterator       it  = mesh.active_elements_begin();
      const MeshBase::element_iterator end = mesh.active_elements_end();

      for ( ; it!=end; ++it)
        {
          Elem *child  = *it;

          std::vector<const Elem*> subactive_family;
          child->total_family_tree(subactive_family);
          for (unsigned int i = 0; i != subactive_family.size(); ++i)
            const_cast<Elem*>(subactive_family[i])->processor_id() = child->processor_id();
        }

      // When the mesh is parallel we cannot guarantee that parents have access to
      // all their children.

      // We will use a brute-force approach here.  Each processor finds its parent
      // elements and sets the parent pid to the minimum of its
      // semilocal descendants.
      // A global reduction is then performed to make sure the true minimum is found.
      // As noted, this is required because we cannot guarantee that a parent has
      // access to all its children on any single processor.
      libmesh_parallel_only(mesh.comm());
      libmesh_assert(MeshTools::n_elem(mesh.unpartitioned_elements_begin(),
                                       mesh.unpartitioned_elements_end()) == 0);

      const dof_id_type max_elem_id = mesh.max_elem_id();

      std::vector<processor_id_type>
        parent_processor_ids (std::min(communication_blocksize,
                                       max_elem_id));

      for (dof_id_type blk=0, last_elem_id=0; last_elem_id<max_elem_id; blk++)
        {
          last_elem_id =
            std::min(static_cast<dof_id_type>((blk+1)*communication_blocksize),
                     max_elem_id);
          const dof_id_type first_elem_id = blk*communication_blocksize;

          std::fill (parent_processor_ids.begin(),
                     parent_processor_ids.end(),
                     DofObject::invalid_processor_id);

          // first build up local contributions to parent_processor_ids
          MeshBase::element_iterator       not_it  = mesh.ancestor_elements_begin();
          const MeshBase::element_iterator not_end = mesh.ancestor_elements_end();

          bool have_parent_in_block = false;

          for ( ; not_it != not_end; ++not_it)
            {
              Elem *parent = *not_it;

              const dof_id_type parent_idx = parent->id();
              libmesh_assert_less (parent_idx, max_elem_id);

              if ((parent_idx >= first_elem_id) &&
                  (parent_idx <  last_elem_id))
                {
                  have_parent_in_block = true;
                  processor_id_type parent_pid = DofObject::invalid_processor_id;

                  std::vector<const Elem*> active_family;
                  parent->active_family_tree(active_family);
                  for (unsigned int i = 0; i != active_family.size(); ++i)
                    parent_pid = std::min (parent_pid, active_family[i]->processor_id());

                  const dof_id_type packed_idx = parent_idx - first_elem_id;
                  libmesh_assert_less (packed_idx, parent_processor_ids.size());

                  parent_processor_ids[packed_idx] = parent_pid;
                }
            }

          // then find the global minimum
          mesh.comm().min (parent_processor_ids);

          // and assign the ids, if we have a parent in this block.
          if (have_parent_in_block)
            for (not_it = mesh.ancestor_elements_begin();
                 not_it != not_end; ++not_it)
              {
                Elem *parent = *not_it;

                const dof_id_type parent_idx = parent->id();

                if ((parent_idx >= first_elem_id) &&
                    (parent_idx <  last_elem_id))
                  {
                    const dof_id_type packed_idx = parent_idx - first_elem_id;
                    libmesh_assert_less (packed_idx, parent_processor_ids.size());

                    const processor_id_type parent_pid =
                      parent_processor_ids[packed_idx];

                    libmesh_assert_not_equal_to (parent_pid, DofObject::invalid_processor_id);

                    parent->processor_id() = parent_pid;
                  }
              }
        }
    }

#endif // LIBMESH_ENABLE_AMR

  STOP_LOG("set_parent_processor_ids()","Partitioner");
}

void libMesh::Partitioner::single_partition ( MeshBase & mesh ) [protected]

Trivially "partitions" the mesh for one processor. Simply loops through the elements and assigns all of them to processor 0. Is is provided as a separate function so that derived classes may use it without reimplementing it.

Definition at line 157 of file partitioner.C.

References libMesh::MeshBase::elements_begin(), libMesh::MeshBase::elements_end(), libMesh::MeshBase::nodes_begin(), libMesh::MeshBase::nodes_end(), and libMesh::START_LOG().

Referenced by libMesh::LinearPartitioner::_do_partition(), libMesh::MetisPartitioner::_do_partition(), libMesh::SFCPartitioner::_do_partition(), libMesh::CentroidPartitioner::_do_partition(), libMesh::ParmetisPartitioner::_do_repartition(), partition(), and repartition().

{
  START_LOG("single_partition()","Partitioner");

  // Loop over all the elements and assign them to processor 0.
  MeshBase::element_iterator       elem_it  = mesh.elements_begin();
  const MeshBase::element_iterator elem_end = mesh.elements_end();

  for ( ; elem_it != elem_end; ++elem_it)
    (*elem_it)->processor_id() = 0;

  // For a single partition, all the nodes are on processor 0
  MeshBase::node_iterator       node_it  = mesh.nodes_begin();
  const MeshBase::node_iterator node_end = mesh.nodes_end();

  for ( ; node_it != node_end; ++node_it)
    (*node_it)->processor_id() = 0;

  STOP_LOG("single_partition()","Partitioner");
}