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//
// Copyright (C) 2008 - 2016 by the deal.II authors
//
// This file is part of the deal.II library.
//
// The deal.II library is free software; you can use it, redistribute
// it, and/or modify it under the terms of the GNU Lesser General
// Public License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
// The full text of the license can be found in the file LICENSE at
// the top level of the deal.II distribution.
//
// ---------------------------------------------------------------------
#ifndef dealii__distributed_tria_h
#define dealii__distributed_tria_h
#include <deal.II/base/config.h>
#include <deal.II/base/subscriptor.h>
#include <deal.II/base/smartpointer.h>
#include <deal.II/base/template_constraints.h>
#include <deal.II/grid/tria.h>
#include <deal.II/base/std_cxx11/function.h>
#include <deal.II/base/std_cxx11/tuple.h>
#include <deal.II/distributed/tria_base.h>
#include <set>
#include <vector>
#include <list>
#include <utility>
#ifdef DEAL_II_WITH_MPI
# include <mpi.h>
#endif
#ifdef DEAL_II_WITH_P4EST
#include <p4est_connectivity.h>
#include <p4est.h>
#include <p4est_ghost.h>
#include <p8est_connectivity.h>
#include <p8est.h>
#include <p8est_ghost.h>
#endif
DEAL_II_NAMESPACE_OPEN
template <int, int> class Triangulation;
#ifdef DEAL_II_WITH_P4EST
namespace internal
{
namespace DoFHandler
{
namespace Policy
{
template <int, int> class ParallelDistributed;
}
}
}
namespace internal
{
namespace p4est
{
/**
* A structure whose explicit specializations contain typedefs to the
* relevant p4est_* and p8est_* types. Using this structure, for example
* by saying <tt>types<dim>::connectivity</tt> we can write code in a
* dimension independent way, either referring to p4est_connectivity_t or
* p8est_connectivity_t, depending on template argument.
*/
template <int> struct types;
template <>
struct types<2>
{
typedef p4est_connectivity_t connectivity;
typedef p4est_t forest;
typedef p4est_tree_t tree;
typedef p4est_quadrant_t quadrant;
typedef p4est_topidx_t topidx;
typedef p4est_locidx_t locidx;
#if DEAL_II_P4EST_VERSION_GTE(0,3,4,3)
typedef p4est_connect_type_t balance_type;
#else
typedef p4est_balance_type_t balance_type;
#endif
typedef p4est_ghost_t ghost;
};
template <>
struct types<3>
{
typedef p8est_connectivity_t connectivity;
typedef p8est_t forest;
typedef p8est_tree_t tree;
typedef p8est_quadrant_t quadrant;
typedef p4est_topidx_t topidx;
typedef p4est_locidx_t locidx;
#if DEAL_II_P4EST_VERSION_GTE(0,3,4,3)
typedef p8est_connect_type_t balance_type;
#else
typedef p8est_balance_type_t balance_type;
#endif
typedef p8est_ghost_t ghost;
};
/**
* Initialize the GeometryInfo<dim>::max_children_per_cell children of the
* cell p4est_cell.
*/
template <int dim>
void
init_quadrant_children
(const typename types<dim>::quadrant &p4est_cell,
typename types<dim>::quadrant (&p4est_children)[GeometryInfo<dim>::max_children_per_cell]);
/**
* Initialize quadrant to represent a coarse cell.
*/
template <int dim>
void
init_coarse_quadrant(typename types<dim>::quadrant &quad);
/**
* Returns whether q1 and q2 are equal
*/
template <int dim>
bool
quadrant_is_equal (const typename types<dim>::quadrant &q1,
const typename types<dim>::quadrant &q2);
//TODO: remove these functions from
//public interface somehow? [TH]
/**
* returns whether q1 is an ancestor of q2
*/
template <int dim>
bool
quadrant_is_ancestor (const typename types<dim>::quadrant &q1,
const typename types<dim>::quadrant &q2);
}
}
//forward declaration of the data type for periodic face pairs
namespace GridTools
{
template <typename CellIterator> struct PeriodicFacePair;
}
namespace parallel
{
namespace distributed
{
/**
* This class acts like the dealii::Triangulation class, but it
* distributes the mesh across a number of different processors when using
* MPI. The class's interface does not add a lot to the
* dealii::Triangulation class but there are a number of difficult
* algorithms under the hood that ensure we always have a load-balanced,
* fully distributed mesh. Use of this class is explained in step-40,
* step-32, the
* @ref distributed
* documentation module, as well as the
* @ref distributed_paper.
* See there for more information. This class satisfies the
* @ref ConceptMeshType "MeshType concept".
*
* @note This class does not support anisotropic refinement, because it
* relies on the p4est library that does not support this. Attempts to
* refine cells anisotropically will result in errors.
*
* @note There is currently no support for distributing 1d triangulations.
*
*
* <h3> Interaction with boundary description </h3>
*
* Refining and coarsening a distributed triangulation is a complicated
* process because cells may have to be migrated from one processor to
* another. On a single processor, materializing that part of the global
* mesh that we want to store here from what we have stored before
* therefore may involve several cycles of refining and coarsening the
* locally stored set of cells until we have finally gotten from the
* previous to the next triangulation. This process is described in more
* detail in the
* @ref distributed_paper.
* Unfortunately, in this process, some information can get lost relating
* to flags that are set by user code and that are inherited from mother
* to child cell but that are not moved along with a cell if that cell is
* migrated from one processor to another.
*
* An example are boundary indicators. Assume, for example, that you start
* with a single cell that is refined once globally, yielding four
* children. If you have four processors, each one owns one cell. Assume
* now that processor 1 sets the boundary indicators of the external
* boundaries of the cell it owns to 42. Since processor 0 does not own
* this cell, it doesn't set the boundary indicators of its ghost cell
* copy of this cell. Now, assume we do several mesh refinement cycles and
* end up with a configuration where this processor suddenly finds itself
* as the owner of this cell. If boundary indicator 42 means that we need
* to integrate Neumann boundary conditions along this boundary, then
* processor 0 will forget to do so because it has never set the boundary
* indicator along this cell's boundary to 42.
*
* The way to avoid this dilemma is to make sure that things like setting
* boundary indicators or material ids is done immediately every time a
* parallel triangulation is refined. This is not necessary for sequential
* triangulations because, there, these flags are inherited from mother to
* child cell and remain with a cell even if it is refined and the
* children are later coarsened again, but this does not hold for
* distributed triangulations. It is made even more difficult by the fact
* that in the process of refining a parallel distributed triangulation,
* the triangulation may call
* dealii::Triangulation::execute_coarsening_and_refinement multiple times
* and this function needs to know about boundaries. In other words, it is
* <i>not</i> enough to just set boundary indicators on newly created
* faces only <i>after</i> calling
* <tt>distributed::parallel::Triangulation::execute_coarsening_and_refinement</tt>:
* it actually has to happen while that function is still running.
*
* The way to do this is by writing a function that sets boundary
* indicators and that will be called by the dealii::Triangulation class.
* The triangulation does not provide a pointer to itself to the function
* being called, nor any other information, so the trick is to get this
* information into the function. C++ provides a nice mechanism for this
* that is best explained using an example:
* @code
* #include <deal.II/base/std_cxx11/bind.h>
*
* template <int dim>
* void set_boundary_ids (parallel::distributed::Triangulation<dim> &triangulation)
* {
* ... set boundary indicators on the triangulation object ...
* }
*
* template <int dim>
* void
* MyClass<dim>::
* create_coarse_mesh (parallel::distributed::Triangulation<dim> &coarse_grid) const
* {
* ... create the coarse mesh ...
*
* coarse_grid.signals.post_refinement.connect
* (std_cxx11::bind (&set_boundary_ids<dim>,
* std_cxx11::ref(coarse_grid)));
*
* }
* @endcode
*
* What the call to <code>std_cxx11::bind</code> does is to produce an
* object that can be called like a function with no arguments. It does so
* by taking the address of a function that does, in fact, take an
* argument but permanently fix this one argument to a reference to the
* coarse grid triangulation. After each refinement step, the
* triangulation will then call the object so created which will in turn
* call <code>set_boundary_ids<dim></code> with the reference to the
* coarse grid as argument.
*
* This approach can be generalized. In the example above, we have used a
* global function that will be called. However, sometimes it is necessary
* that this function is in fact a member function of the class that
* generates the mesh, for example because it needs to access run-time
* parameters. This can be achieved as follows: assuming the
* <code>set_boundary_ids()</code> function has been declared as a (non-
* static, but possibly private) member function of the
* <code>MyClass</code> class, then the following will work:
* @code
* #include <deal.II/base/std_cxx11/bind.h>
*
* template <int dim>
* void
* MyClass<dim>::
* set_boundary_ids (parallel::distributed::Triangulation<dim> &triangulation) const
* {
* ... set boundary indicators on the triangulation object ...
* }
*
* template <int dim>
* void
* MyClass<dim>::
* create_coarse_mesh (parallel::distributed::Triangulation<dim> &coarse_grid) const
* {
* ... create the coarse mesh ...
*
* coarse_grid.signals.post_refinement.connect
* (std_cxx11::bind (&MyGeometry<dim>::set_boundary_ids,
* std_cxx11::cref(*this),
* std_cxx11::ref(coarse_grid)));
* }
* @endcode
* Here, like any other member function, <code>set_boundary_ids</code>
* implicitly takes a pointer or reference to the object it belongs to as
* first argument. <code>std::bind</code> again creates an object that can
* be called like a global function with no arguments, and this object in
* turn calls <code>set_boundary_ids</code> with a pointer to the current
* object and a reference to the triangulation to work on. Note that
* because the <code>create_coarse_mesh</code> function is declared as
* <code>const</code>, it is necessary that the
* <code>set_boundary_ids</code> function is also declared
* <code>const</code>.
*
* <b>Note:</b>For reasons that have to do with the way the
* parallel::distributed::Triangulation is implemented, functions that
* have been attached to the post-refinement signal of the triangulation
* are called more than once, sometimes several times, every time the
* triangulation is actually refined.
*
*
* @author Wolfgang Bangerth, Timo Heister 2008, 2009, 2010, 2011
* @ingroup distributed
*/
template <int dim, int spacedim = dim>
class Triangulation : public dealii::parallel::Triangulation<dim,spacedim>
{
public:
/**
* A typedef that is used to to identify cell iterators. The concept of
* iterators is discussed at length in the
* @ref Iterators "iterators documentation module".
*
* The current typedef identifies cells in a triangulation. You can find
* the exact type it refers to in the base class's own typedef, but it
* should be TriaIterator<CellAccessor<dim,spacedim> >. The TriaIterator
* class works like a pointer that when you dereference it yields an
* object of type CellAccessor. CellAccessor is a class that identifies
* properties that are specific to cells in a triangulation, but it is
* derived (and consequently inherits) from TriaAccessor that describes
* what you can ask of more general objects (lines, faces, as well as
* cells) in a triangulation.
*
* @ingroup Iterators
*/
typedef typename dealii::Triangulation<dim,spacedim>::cell_iterator cell_iterator;
/**
* A typedef that is used to to identify
* @ref GlossActive "active cell iterators".
* The concept of iterators is discussed at length in the
* @ref Iterators "iterators documentation module".
*
* The current typedef identifies active cells in a triangulation. You
* can find the exact type it refers to in the base class's own typedef,
* but it should be TriaActiveIterator<CellAccessor<dim,spacedim> >. The
* TriaActiveIterator class works like a pointer to active objects that
* when you dereference it yields an object of type CellAccessor.
* CellAccessor is a class that identifies properties that are specific
* to cells in a triangulation, but it is derived (and consequently
* inherits) from TriaAccessor that describes what you can ask of more
* general objects (lines, faces, as well as cells) in a triangulation.
*
* @ingroup Iterators
*/
typedef typename dealii::Triangulation<dim,spacedim>::active_cell_iterator active_cell_iterator;
typedef typename dealii::Triangulation<dim,spacedim>::CellStatus CellStatus;
/**
* Configuration flags for distributed Triangulations to be set in the
* constructor. Settings can be combined using bitwise OR.
*/
enum Settings
{
/**
* Default settings, other options are disabled.
*/
default_setting = 0x0,
/**
* If set, the deal.II mesh will be reconstructed from the coarse mesh
* every time a repartioning in p4est happens. This can be a bit more
* expensive, but guarantees the same memory layout and therefore cell
* ordering in the deal.II mesh. As assembly is done in the deal.II
* cell ordering, this flag is required to get reproducible behaviour
* after snapshot/resume.
*/
mesh_reconstruction_after_repartitioning = 0x1,
/**
* This flags needs to be set to use the geometric multigrid
* functionality. This option requires additional computation and
* communication. Note: geometric multigrid is still a work in
* progress.
*/
construct_multigrid_hierarchy = 0x2,
/**
* Setting this flag will disable automatic repartioning of the cells
* after a refinement cycle. It can be executed manually by calling
* repartition().
*/
no_automatic_repartitioning = 0x4
};
/**
* Constructor.
*
* @param mpi_communicator denotes the MPI communicator to be used for
* the triangulation.
*
* @param smooth_grid Degree and kind of mesh smoothing to be applied to
* the mesh. See the dealii::Triangulation class for a description of
* the kinds of smoothing operations that can be applied.
*
* @param settings See the description of the Settings enumerator.
*
* @note This class does not currently support the
* <code>check_for_distorted_cells</code> argument provided by the base
* class.
*
* @note While it is possible to pass all of the mesh smoothing flags
* listed in the base class to objects of this type, it is not always
* possible to honor all of these smoothing options if they would
* require knowledge of refinement/coarsening flags on cells not locally
* owned by this processor. As a consequence, for some of these flags,
* the ultimate number of cells of the parallel triangulation may depend
* on the number of processors into which it is partitioned. On the
* other hand, if no smoothing flags are passed, if you always mark the
* same cells of the mesh, you will always get the exact same refined
* mesh independent of the number of processors into which the
* triangulation is partitioned.
*/
Triangulation (MPI_Comm mpi_communicator,
const typename dealii::Triangulation<dim,spacedim>::MeshSmoothing
smooth_grid = (dealii::Triangulation<dim,spacedim>::none),
const Settings settings = default_setting);
/**
* Destructor.
*/
virtual ~Triangulation ();
/**
* Reset this triangulation into a virgin state by deleting all data.
*
* Note that this operation is only allowed if no subscriptions to this
* object exist any more, such as DoFHandler objects using it.
*/
virtual void clear ();
/**
* Implementation of the same function as in the base class.
*/
virtual void copy_triangulation (const dealii::Triangulation<dim, spacedim> &old_tria);
/**
* Create a triangulation as documented in the base class.
*
* This function also sets up the various data structures necessary to
* distribute a mesh across a number of processors. This will be
* necessary once the mesh is being refined, though we will always keep
* the entire coarse mesh that is generated by this function on all
* processors.
*/
virtual void create_triangulation (const std::vector<Point<spacedim> > &vertices,
const std::vector<CellData<dim> > &cells,
const SubCellData &subcelldata);
/**
* Coarsen and refine the mesh according to refinement and coarsening
* flags set.
*
* Since the current processor only has control over those cells it owns
* (i.e. the ones for which <code>cell-@>subdomain_id() ==
* this-@>locally_owned_subdomain()</code>), refinement and coarsening
* flags are only respected for those locally owned cells. Flags may be
* set on other cells as well (and may often, in fact, if you call
* dealii::Triangulation::prepare_coarsening_and_refinement()) but will
* be largely ignored: the decision to refine the global mesh will only
* be affected by flags set on locally owned cells.
*
* @note This function by default partitions the mesh in such a way that
* the number of cells on all processors is roughly equal. If you want
* to set weights for partitioning, e.g. because some cells are more
* expensive to compute than others, you can use the signal cell_weight
* as documented in the dealii::Triangulation class. This function will
* check whether a function is connected to the signal and if so use it.
* If you prefer to repartition the mesh yourself at user-defined
* intervals only, you can create your triangulation object by passing
* the parallel::distributed::Triangulation::no_automatic_repartitioning
* flag to the constructor, which ensures that calling the current
* function only refines and coarsens the triangulation, but doesn't
* partition it. You can then call the repartition() function manually.
* The usage of the cell_weights signal is identical in both cases, if a
* function is connected to the signal it will be used to balance the
* calculated weights, otherwise the number of cells is balanced.
*/
virtual void execute_coarsening_and_refinement ();
/**
* Override the implementation of prepare_coarsening_and_refinement from
* the base class. This is necessary if periodic boundaries are enabled
* and the level difference over vertices over the periodic boundary
* must be not more than 2:1.
*/
virtual bool prepare_coarsening_and_refinement ();
/**
* Manually repartition the active cells between processors. Normally
* this repartitioning will happen automatically when calling
* execute_coarsening_and_refinement() (or refine_global()) unless the
* @p no_automatic_repartitioning is set in the constructor. Setting the
* flag and then calling repartition() gives the same result.
*
* If you want to transfer data (using SolutionTransfer or manually with
* register_data_attach() and notify_ready_to_unpack()), you need to set
* it up twice: once when calling execute_coarsening_and_refinement(),
* which will handle coarsening and refinement but obviously won't ship
* any data between processors, and a second time when calling
* repartition(). Here, no coarsening and refinement will be done but
* information will be packed and shipped to different processors. In
* other words, you probably want to treat a call to repartition() in
* the same way as execute_coarsening_and_refinement() with respect to
* dealing with data movement (SolutionTransfer, etc.).
*
* @note If no function is connected to the cell_weight signal described
* in the dealii::Triangulation class, this function will balance the
* number of cells on each processor. If one or more functions are
* connected, it will calculate the sum of the weights and balance the
* weights across processors. The only requirement on the weights is
* that every cell's weight is positive and that the sum over all
* weights on all processors can be formed using a 64-bit integer.
* Beyond that, it is your choice how you want to interpret the weights.
* A common approach is to consider the weights proportional to the cost
* of doing computations on a cell, e.g., by summing the time for
* assembly and solving. In practice, determining this cost is of course
* not trivial since we don't solve on isolated cells, but on the entire
* mesh. In such cases, one could, for example, choose the weight equal
* to the number of unknowns per cell (in the context of hp finite
* element methods), or using a heuristic that estimates the cost on
* each cell depending on whether, for example, one has to run some
* expensive algorithm on some cells but not others (such as forming
* boundary integrals during the assembly only on cells that are
* actually at the boundary, or computing expensive nonlinear terms only
* on some cells but not others, e.g., in the elasto-plastic problem in
* step-42).
*/
void repartition ();
/**
* When vertices have been moved locally, for example using code like
* @code
* cell->vertex(0) = new_location;
* @endcode
* then this function can be used to update the location of vertices
* between MPI processes.
*
* All the vertices that have been moved and might be in the ghost layer
* of a process have to be reported in the @p vertex_locally_moved
* argument. This ensures that that part of the information that has to
* be send between processes is actually sent. Additionally, it is quite
* important that vertices on the boundary between processes are
* reported on exactly one process (e.g. the one with the highest id).
* Otherwise we could expect undesirable results if multiple processes
* move a vertex differently. A typical strategy is to let processor $i$
* move those vertices that are adjacent to cells whose owners include
* processor $i$ but no other processor $j$ with $j<i$; in other words,
* for vertices at the boundary of a subdomain, the processor with the
* lowest subdomain id "owns" a vertex.
*
* @note It only makes sense to move vertices that are either located on
* locally owned cells or on cells in the ghost layer. This is because
* you can be sure that these vertices indeed exist on the finest mesh
* aggregated over all processors, whereas vertices on artificial cells
* but not at least in the ghost layer may or may not exist on the
* globally finest mesh. Consequently, the @p vertex_locally_moved
* argument may not contain vertices that aren't at least on ghost
* cells.
*
* @note This function moves vertices in such a way that on every
* processor, the vertices of every locally owned and ghost cell is
* consistent with the corresponding location of these cells on other
* processors. On the other hand, the locations of artificial cells will
* in general be wrong since artificial cells may or may not exist on
* other processors and consequently it is not possible to determine
* their location in any way. This is not usually a problem since one
* never does anything on artificial cells. However, it may lead to
* problems if the mesh with moved vertices is refined in a later step.
* If that's what you want to do, the right way to do it is to save the
* offset applied to every vertex, call this function, and before
* refining or coarsening the mesh apply the opposite offset and call
* this function again.
*
* @param vertex_locally_moved A bitmap indicating which vertices have
* been moved. The size of this array must be equal to
* Triangulation::n_vertices() and must be a subset of those vertices
* flagged by GridTools::get_locally_owned_vertices().
*
* @see This function is used, for example, in
* GridTools::distort_random().
*/
void
communicate_locally_moved_vertices (const std::vector<bool> &vertex_locally_moved);
/**
* Returns true if the triangulation has hanging nodes.
*
* In the context of parallel distributed triangulations, every
* processor stores only that part of the triangulation it locally owns.
* However, it also stores the entire coarse mesh, and to guarantee the
* 2:1 relationship between cells, this may mean that there are hanging
* nodes between cells that are not locally owned or ghost cells (i.e.,
* between ghost cells and artificial cells, or between artificial and
* artificial cells; see
* @ref GlossArtificialCell "the glossary").
* One is not typically interested in this case, so the function returns
* whether there are hanging nodes between any two cells of the "global"
* mesh, i.e., the union of locally owned cells on all processors.
*/
virtual
bool has_hanging_nodes() const;
/**
* Return the local memory consumption in bytes.
*/
virtual std::size_t memory_consumption () const;
/**
* Return the local memory consumption contained in the p4est data
* structures alone. This is already contained in memory_consumption()
* but made available separately for debugging purposes.
*/
virtual std::size_t memory_consumption_p4est () const;
/**
* A collective operation that produces a sequence of output files with
* the given file base name that contain the mesh in VTK format.
*
* More than anything else, this function is useful for debugging the
* interface between deal.II and p4est.
*/
void write_mesh_vtk (const char *file_basename) const;
/**
* Produce a check sum of the triangulation. This is a collective
* operation and is mostly useful for debugging purposes.
*/
unsigned int get_checksum () const;
/**
* Save the refinement information from the coarse mesh into the given
* file. This file needs to be reachable from all nodes in the
* computation on a shared network file system. See the SolutionTransfer
* class on how to store solution vectors into this file. Additional
* cell-based data can be saved using register_data_attach().
*/
void save(const char *filename) const;
/**
* Load the refinement information saved with save() back in. The mesh
* must contain the same coarse mesh that was used in save() before
* calling this function.
*
* You do not need to load with the same number of MPI processes that
* you saved with. Rather, if a mesh is loaded with a different number
* of MPI processes than used at the time of saving, the mesh is
* repartitioned appropriately. Cell-based data that was saved with
* register_data_attach() can be read in with notify_ready_to_unpack()
* after calling load().
*
* If you use p4est version > 0.3.4.2 the @p autopartition flag tells
* p4est to ignore the partitioning that the triangulation had when it
* was saved and make it uniform upon loading. If @p autopartition is
* set to false, the triangulation is only repartitioned if needed (i.e.
* if a different number of MPI processes is encountered).
*/
void load(const char *filename,
const bool autopartition = true);
/**
* Register a function with the current Triangulation object that will
* be used to attach data to active cells before
* execute_coarsening_and_refinement(). In
* execute_coarsening_and_refinement() the Triangulation will call the
* given function pointer and provide @p size bytes to store data. If
* necessary, this data will be transferred to the new owner of that
* cell during repartitioning the tree. See notify_ready_to_unpack() on
* how to retrieve the data.
*
* Callers need to store the return value. It specifies an offset of
* the position at which data can later be retrieved during a call to
* notify_ready_to_unpack().
*
* The CellStatus argument in the callback function will tell you if the
* given cell will be coarsened, refined, or will persist as is (this
* can be different than the coarsen and refine flags set by you). If it
* is
*
* - CELL_PERIST: the cell won't be refined/coarsened, but might be
* moved to a different processor - CELL_REFINE: this cell will be
* refined into 4/8 cells, you can not access the children (because they
* don't exist yet) - CELL_COARSEN: the children of this cell will be
* coarsened into the given cell (you can access the active children!)
*
* When unpacking the data with notify_ready_to_unpack() you can access
* the children of the cell if the status is CELL_REFINE but not for
* CELL_COARSEN. As a consequence you need to handle coarsening while
* packing and refinement during unpacking.
*
* @note The two functions can also be used for serialization of data
* using save() and load() in the same way. Then the status will always
* be CELL_PERSIST.
*/
unsigned int
register_data_attach (const std::size_t size,
const std_cxx11::function<void (const cell_iterator &,
const CellStatus,
void *)> &pack_callback);
/**
* The supplied callback function is called for each newly locally owned
* cell and corresponding data saved with register_data_attach(). This
* function needs to be called after execute_coarsening_and_refinement()
* with the offset returned by register_data_attach().
*
* The CellStatus will indicate if the cell was refined, coarsened, or
* persisted unchanged. The cell_iterator will either by an active,
* locally owned cell (if the cell was not refined), or the immediate
* parent if it was refined during execute_coarsening_and_refinement().
* Therefore, contrary to during register_data_attach(), you can now
* access the children if the status is CELL_REFINE but no longer for
* callbacks with status CELL_COARSEN.
*/
void
notify_ready_to_unpack (const unsigned int offset,
const std_cxx11::function<void (const cell_iterator &,
const CellStatus,
const void *)> &unpack_callback);
/**
* Return a permutation vector for the order the coarse cells are handed
* off to p4est. For example the value of the $i$th element in this
* vector is the index of the deal.II coarse cell (counting from
* begin(0)) that corresponds to the $i$th tree managed by p4est.
*/
const std::vector<types::global_dof_index> &
get_p4est_tree_to_coarse_cell_permutation() const;
/**
* Return a permutation vector for the mapping from the coarse deal
* cells to the p4est trees. This is the inverse of
* get_p4est_tree_to_coarse_cell_permutation.
*/
const std::vector<types::global_dof_index> &
get_coarse_cell_to_p4est_tree_permutation() const;
/**
* Join faces in the p4est forest for periodic boundary conditions. As a
* result, each pair of faces will differ by at most one refinement
* level and ghost neighbors will be available across these faces.
*
* The vector can be filled by the function
* GridTools::collect_periodic_faces.
*
* For more information on periodic boundary conditions see
* GridTools::collect_periodic_faces,
* DoFTools::make_periodicity_constraints and step-45.
*
* @note Before this function can be used the Triangulation has to be
* initialized and must not be refined. Calling this function more than
* once is possible, but not recommended: The function destroys and
* rebuilds the p4est forest each time it is called.
*/
void
add_periodicity
(const std::vector<GridTools::PeriodicFacePair<cell_iterator> > &);
private:
/**
* Override the function to update the number cache so we can fill data
* like @p level_ghost_owners.
*
*/
virtual void update_number_cache ();
/**
* store the Settings.
*/
Settings settings;
/**
* A flag that indicates whether the triangulation has actual content.
*/
bool triangulation_has_content;
/**
* A data structure that holds the connectivity between trees. Since
* each tree is rooted in a coarse grid cell, this data structure holds
* the connectivity between the cells of the coarse grid.
*/
typename dealii::internal::p4est::types<dim>::connectivity *connectivity;
/**
* A data structure that holds the local part of the global
* triangulation.
*/
typename dealii::internal::p4est::types<dim>::forest *parallel_forest;
/**
* A data structure that holds some information about the ghost cells of
* the triangulation.
*/
typename dealii::internal::p4est::types<dim>::ghost *parallel_ghost;
/**
* A flag that indicates whether refinement of a triangulation is
* currently in progress. This flag is used to disambiguate whether a
* call to execute_coarsening_and_triangulation came from the outside or
* through a recursive call. While the first time we want to take over
* work to copy things from a refined p4est, the other times we don't
* want to get in the way as these latter calls to
* Triangulation::execute_coarsening_and_refinement() are simply there
* in order to re-create a triangulation that matches the p4est.
*/
bool refinement_in_progress;
/**
* number of bytes that get attached to the Triangulation through
* register_data_attach() for example SolutionTransfer.
*/
unsigned int attached_data_size;
/**
* number of functions that get attached to the Triangulation through
* register_data_attach() for example SolutionTransfer.
*/
unsigned int n_attached_datas;
/**
* number of functions that need to unpack their data after a call from
* load()
*/
unsigned int n_attached_deserialize;
typedef std_cxx11::function<
void(typename Triangulation<dim,spacedim>::cell_iterator, CellStatus, void *)
> pack_callback_t;
typedef std::pair<unsigned int, pack_callback_t> callback_pair_t;
typedef std::list<callback_pair_t> callback_list_t;
/**
* List of callback functions registered by register_data_attach() that
* are going to be called for packing data.
*/
callback_list_t attached_data_pack_callbacks;
/**
* Two arrays that store which p4est tree corresponds to which coarse
* grid cell and vice versa. We need these arrays because p4est goes
* with the original order of coarse cells when it sets up its forest,
* and then applies the Morton ordering within each tree. But if coarse
* grid cells are badly ordered this may mean that individual parts of
* the forest stored on a local machine may be split across coarse grid
* cells that are not geometrically close. Consequently, we apply a
* hierarchical preordering according to
* SparsityTools::reorder_hierarchical() to ensure that the part of the
* forest stored by p4est is located on geometrically close coarse grid
* cells.
*/
std::vector<types::global_dof_index> coarse_cell_to_p4est_tree_permutation;
std::vector<types::global_dof_index> p4est_tree_to_coarse_cell_permutation;
/**
* If add_periodicity() is called, this variable stores the given
* periodic face pairs on level 0 for later access during the
* identification of ghost cells for the multigrid hierarchy.
*/
std::vector<GridTools::PeriodicFacePair<cell_iterator> > periodic_face_pairs_level_0;
/**
* Return a pointer to the p4est tree that belongs to the given
* dealii_coarse_cell_index()
*/
typename dealii::internal::p4est::types<dim>::tree *
init_tree(const int dealii_coarse_cell_index) const;
/**
* The function that computes the permutation between the two data
* storage schemes.
*/
void setup_coarse_cell_to_p4est_tree_permutation ();
/**
* Take the contents of a newly created triangulation we are attached to
* and copy it to p4est data structures.
*
* This function exists in 2d and 3d variants.
*/
void copy_new_triangulation_to_p4est (dealii::internal::int2type<2>);
void copy_new_triangulation_to_p4est (dealii::internal::int2type<3>);
/**
* Copy the local part of the refined forest from p4est into the
* attached triangulation.
*/
void copy_local_forest_to_triangulation ();
/**
* Internal function notifying all registered classes to attach their
* data before repartitioning occurs. Called from
* execute_coarsening_and_refinement().
*/
void attach_mesh_data();
/**
* Internal function notifying all registered slots to provide their
* weights before repartitioning occurs. Called from
* execute_coarsening_and_refinement() and repartition().
*
* @return A vector of unsigned integers representing the weight or
* computational load of every cell after the refinement/coarsening/
* repartition cycle. Note that the number of entries does not need to
* be equal to either n_active_cells or n_locally_owned_active_cells,
* because the triangulation is not updated yet. The weights are sorted
* in the order that p4est will encounter them while iterating over
* them.
*/
std::vector<unsigned int>
get_cell_weights();
/**
* Fills a map that, for each vertex, lists all the processors whose
* subdomains are adjacent to that vertex. Used by
* DoFHandler::Policy::ParallelDistributed.
*/
void
fill_vertices_with_ghost_neighbors
(std::map<unsigned int, std::set<dealii::types::subdomain_id> >
&vertices_with_ghost_neighbors);
/**
* Fills a map that, for each vertex, lists all the processors whose
* subdomains are adjacent to that vertex on the given level for the
* multigrid hierarchy. Used by DoFHandler::Policy::ParallelDistributed.
*/
void
fill_level_vertices_with_ghost_neighbors
(const unsigned int level,
std::map<unsigned int, std::set<dealii::types::subdomain_id> >
&vertices_with_ghost_neighbors);
/**
* This method returns a bit vector of length tria.n_vertices()
* indicating the locally active vertices on a level, i.e., the vertices
* touched by the locally owned level cells for use in geometric
* multigrid (possibly including the vertices due to periodic boundary
* conditions) are marked by true.
*
* Used by DoFHandler::Policy::ParallelDistributed.
*/
std::vector<bool>
mark_locally_active_vertices_on_level(const unsigned int level) const;
template <int, int> friend class dealii::internal::DoFHandler::Policy::ParallelDistributed;
};
/**
* Specialization of the general template for the 1d case. There is
* currently no support for distributing 1d triangulations. Consequently,
* all this class does is throw an exception.
*/
template <int spacedim>
class Triangulation<1,spacedim> : public dealii::parallel::Triangulation<1,spacedim>
{
public:
/**
* Constructor. The argument denotes the MPI communicator to be used for
* the triangulation.
*/
Triangulation (MPI_Comm mpi_communicator);
/**
* Destructor.
*/
virtual ~Triangulation ();
/**
* Returns a permutation vector for the order the coarse cells are
* handed of to p4est. For example the first element i in this vector
* denotes that the first cell in hierarchical ordering is the ith deal
* cell starting from begin(0).
*/
const std::vector<types::global_dof_index> &
get_p4est_tree_to_coarse_cell_permutation() const;
/**
* When vertices have been moved locally, for example using code like
* @code
* cell->vertex(0) = new_location;
* @endcode
* then this function can be used to update the location of vertices
* between MPI processes.
*
* All the vertices that have been moved and might be in the ghost layer
* of a process have to be reported in the @p vertex_locally_moved
* argument. This ensures that that part of the information that has to
* be send between processes is actually sent. Additionally, it is quite
* important that vertices on the boundary between processes are
* reported on exactly one process (e.g. the one with the highest id).
* Otherwise we could expect undesirable results if multiple processes
* move a vertex differently. A typical strategy is to let processor $i$
* move those vertices that are adjacent to cells whose owners include
* processor $i$ but no other processor $j$ with $j<i$; in other words,
* for vertices at the boundary of a subdomain, the processor with the
* lowest subdomain id "owns" a vertex.
*
* @note It only makes sense to move vertices that are either located on
* locally owned cells or on cells in the ghost layer. This is because
* you can be sure that these vertices indeed exist on the finest mesh
* aggregated over all processors, whereas vertices on artificial cells
* but not at least in the ghost layer may or may not exist on the
* globally finest mesh. Consequently, the @p vertex_locally_moved
* argument may not contain vertices that aren't at least on ghost
* cells.
*
* @see This function is used, for example, in
* GridTools::distort_random().
*/
void
communicate_locally_moved_vertices (const std::vector<bool> &vertex_locally_moved);
/**
* Dummy arrays. This class isn't usable but the compiler wants to see
* these variables at a couple places anyway.
*/
std::vector<types::global_dof_index> coarse_cell_to_p4est_tree_permutation;
std::vector<types::global_dof_index> p4est_tree_to_coarse_cell_permutation;
/**
* dummy settings
*/
enum Settings
{
default_setting = 0x0,
mesh_reconstruction_after_repartitioning = 0x1,
construct_multigrid_hierarchy = 0x2
};
//TODO: The following variable should really be private, but it is used in dof_handler_policy.cc ...
/**
* dummy settings object
*/
Settings settings;
/**
* Like above, this method, which is only implemented for dim = 2 or 3,
* needs a stub because it is used in dof_handler_policy.cc
*/
void
fill_vertices_with_ghost_neighbors
(std::map<unsigned int, std::set<dealii::types::subdomain_id> >
&vertices_with_ghost_neighbors);
/**
* Like above, this method, which is only implemented for dim = 2 or 3,
* needs a stub because it is used in dof_handler_policy.cc
*/
void
fill_level_vertices_with_ghost_neighbors
(const unsigned int level,
std::map<unsigned int, std::set<dealii::types::subdomain_id> >
&vertices_with_ghost_neighbors);
/**
* Like above, this method, which is only implemented for dim = 2 or 3,
* needs a stub because it is used in dof_handler_policy.cc
*/
std::vector<bool>
mark_locally_active_vertices_on_level(const unsigned int level) const;
};
}
}
#else // DEAL_II_WITH_P4EST
namespace parallel
{
namespace distributed
{
/**
* Dummy class the compiler chooses for parallel distributed
* triangulations if we didn't actually configure deal.II with the p4est
* library. The existence of this class allows us to refer to
* parallel::distributed::Triangulation objects throughout the library
* even if it is disabled.
*
* Since the constructor of this class is private, no such objects can
* actually be created if we don't have p4est available.
*/
template <int dim, int spacedim = dim>
class Triangulation : public dealii::parallel::Triangulation<dim,spacedim>
{
private:
/**
* Constructor.
*/
Triangulation ();
};
}
}
#endif
DEAL_II_NAMESPACE_CLOSE
#endif
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