Reference documentation for deal.II version Git 040c6ad7d4 2020-09-26 18:01:03 +0200
Particles::ParticleHandler< dim, spacedim > Class Template Reference

#include <deal.II/particles/data_out.h>

Inheritance diagram for Particles::ParticleHandler< dim, spacedim >:
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struct  Signals

## Public Types

using particle_iterator = ParticleIterator< dim, spacedim >

using particle_iterator_range = boost::iterator_range< particle_iterator >

## Public Member Functions

ParticleHandler ()

ParticleHandler (const Triangulation< dim, spacedim > &tria, const Mapping< dim, spacedim > &mapping, const unsigned int n_properties=0)

virtual ~ParticleHandler () override=default

void initialize (const Triangulation< dim, spacedim > &tria, const Mapping< dim, spacedim > &mapping, const unsigned int n_properties=0)

void copy_from (const ParticleHandler< dim, spacedim > &particle_handler)

void clear ()

void clear_particles ()

void update_cached_numbers ()

particle_iterator begin () const

particle_iterator begin ()

particle_iterator end () const

particle_iterator end ()

particle_iterator begin_ghost () const

particle_iterator begin_ghost ()

particle_iterator end_ghost () const

particle_iterator end_ghost ()

types::particle_index n_particles_in_cell (const typename Triangulation< dim, spacedim >::active_cell_iterator &cell) const

particle_iterator_range particles_in_cell (const typename Triangulation< dim, spacedim >::active_cell_iterator &cell)

particle_iterator_range particles_in_cell (const typename Triangulation< dim, spacedim >::active_cell_iterator &cell) const

void remove_particle (const particle_iterator &particle)

particle_iterator insert_particle (const Particle< dim, spacedim > &particle, const typename Triangulation< dim, spacedim >::active_cell_iterator &cell)

void insert_particles (const std::multimap< typename Triangulation< dim, spacedim >::active_cell_iterator, Particle< dim, spacedim >> &particles)

void insert_particles (const std::vector< Point< spacedim >> &positions)

std::map< unsigned int, IndexSetinsert_global_particles (const std::vector< Point< spacedim >> &positions, const std::vector< std::vector< BoundingBox< spacedim >>> &global_bounding_boxes, const std::vector< std::vector< double >> &properties={}, const std::vector< types::particle_index > &ids={})

std::map< unsigned int, IndexSetinsert_global_particles (const std::vector< Particle< dim, spacedim >> &particles, const std::vector< std::vector< BoundingBox< spacedim >>> &global_bounding_boxes)

template<class VectorType >
std::enable_if< std::is_convertible< VectorType *, Function< spacedim > * >::value==false >::type set_particle_positions (const VectorType &input_vector, const bool displace_particles=true)

void set_particle_positions (const std::vector< Point< spacedim >> &new_positions, const bool displace_particles=true)

void set_particle_positions (const Function< spacedim > &function, const bool displace_particles=true)

template<class VectorType >
void get_particle_positions (VectorType &output_vector, const bool add_to_output_vector=false)

void get_particle_positions (std::vector< Point< spacedim >> &positions, const bool add_to_output_vector=false)

void register_additional_store_load_functions (const std::function< std::size_t()> &size_callback, const std::function< void *(const particle_iterator &, void *)> &store_callback, const std::function< const void *(const particle_iterator &, const void *)> &load_callback)

types::particle_index n_global_particles () const

types::particle_index n_global_max_particles_per_cell () const

types::particle_index n_locally_owned_particles () const

types::particle_index get_next_free_particle_index () const

IndexSet locally_relevant_ids () const

unsigned int n_properties_per_particle () const

PropertyPoolget_property_pool () const

void sort_particles_into_subdomains_and_cells ()

void exchange_ghost_particles ()

void register_store_callback_function ()

template<class Archive >
void serialize (Archive &ar, const unsigned int version)

Subscriptor functionality

Classes derived from Subscriptor provide a facility to subscribe to this object. This is mostly used by the SmartPointer class.

void subscribe (std::atomic< bool > *const validity, const std::string &identifier="") const

void unsubscribe (std::atomic< bool > *const validity, const std::string &identifier="") const

unsigned int n_subscriptions () const

template<typename StreamType >
void list_subscribers (StreamType &stream) const

void list_subscribers () const

## Static Public Member Functions

static ::ExceptionBaseExcInUse (int arg1, std::string arg2, std::string arg3)

static ::ExceptionBaseExcNoSubscriber (std::string arg1, std::string arg2)

Signals signals

## Private Member Functions

void send_recv_particles (const std::map< types::subdomain_id, std::vector< particle_iterator >> &particles_to_send, std::multimap< internal::LevelInd, Particle< dim, spacedim >> &received_particles, const std::map< types::subdomain_id, std::vector< typename Triangulation< dim, spacedim >::active_cell_iterator >> &new_cells_for_particles=std::map< types::subdomain_id, std::vector< typename Triangulation< dim, spacedim >::active_cell_iterator >>())

std::vector< char > store_particles (const typename Triangulation< dim, spacedim >::cell_iterator &cell, const typename Triangulation< dim, spacedim >::CellStatus status) const

void load_particles (const typename Triangulation< dim, spacedim >::cell_iterator &cell, const typename Triangulation< dim, spacedim >::CellStatus status, const boost::iterator_range< std::vector< char >::const_iterator > &data_range)

## Private Attributes

SmartPointer< const Triangulation< dim, spacedim >, ParticleHandler< dim, spacedim > > triangulation

SmartPointer< const Mapping< dim, spacedim >, ParticleHandler< dim, spacedim > > mapping

std::multimap< internal::LevelInd, Particle< dim, spacedim > > particles

std::multimap< internal::LevelInd, Particle< dim, spacedim > > ghost_particles

types::particle_index global_number_of_particles

unsigned int global_max_particles_per_cell

types::particle_index next_free_particle_index

std::unique_ptr< PropertyPoolproperty_pool

std::function< std::size_t()> size_callback

std::function< void *(const particle_iterator &, void *)> store_callback

std::function< const void *(const particle_iterator &, const void *)> load_callback

unsigned int handle

std::unique_ptr< GridTools::Cache< dim, spacedim > > triangulation_cache

## Detailed Description

### template<int dim, int spacedim = dim> class Particles::ParticleHandler< dim, spacedim >

This class manages the storage and handling of particles. It provides the data structures necessary to store particles efficiently, accessor functions to iterate over particles and find particles, and algorithms to distribute particles in parallel domains. Note that the class is designed in a similar way as the triangulation class. In particular, we call particles in the domain of the local process local particles, and particles that belong to neighbor processes and live in the ghost cells around the locally owned domain "ghost particles".

This class is used in step-70.

Definition at line 32 of file data_out.h.

## ◆ particle_iterator

template<int dim, int spacedim = dim>
 using Particles::ParticleHandler< dim, spacedim >::particle_iterator = ParticleIterator

A type that can be used to iterate over all particles in the domain.

Definition at line 66 of file particle_handler.h.

## ◆ particle_iterator_range

template<int dim, int spacedim = dim>
 using Particles::ParticleHandler< dim, spacedim >::particle_iterator_range = boost::iterator_range

A type that represents a range of particles.

Definition at line 71 of file particle_handler.h.

## ◆ ParticleHandler() [1/2]

template<int dim, int spacedim>
 Particles::ParticleHandler< dim, spacedim >::ParticleHandler ( )

Default constructor.

Definition at line 88 of file particle_handler.cc.

## ◆ ParticleHandler() [2/2]

template<int dim, int spacedim>
 Particles::ParticleHandler< dim, spacedim >::ParticleHandler ( const Triangulation< dim, spacedim > & tria, const Mapping< dim, spacedim > & mapping, const unsigned int n_properties = 0 )

Constructor that initializes the particle handler with a given triangulation and mapping. Since particles are stored in respect to their surrounding cells this information is necessary to correctly organize the particle collection. This constructor is equivalent to calling the default constructor and the initialize function.

Definition at line 105 of file particle_handler.cc.

## ◆ ~ParticleHandler()

template<int dim, int spacedim = dim>
 virtual Particles::ParticleHandler< dim, spacedim >::~ParticleHandler ( )
overridevirtualdefault

Destructor.

## ◆ initialize()

template<int dim, int spacedim>
 void Particles::ParticleHandler< dim, spacedim >::initialize ( const Triangulation< dim, spacedim > & tria, const Mapping< dim, spacedim > & mapping, const unsigned int n_properties = 0 )

Initialize the particle handler. This function does not clear the internal data structures, it just sets the triangulation and the mapping to be used.

Definition at line 130 of file particle_handler.cc.

## ◆ copy_from()

template<int dim, int spacedim>
 void Particles::ParticleHandler< dim, spacedim >::copy_from ( const ParticleHandler< dim, spacedim > & particle_handler )

Copy the state of particle handler particle_handler into the current object. This will copy all particles and properties and leave this object as an identical copy of particle_handler. Existing particles in this object are deleted. Be aware that this does not copy functions that are connected to the signals of particle_handler, nor does it connect the current object's member functions to triangulation signals, which must be done by the caller if necessary, that is if the particle_handler had connected functions.

This function is expensive as it has to duplicate all data in particle_handler, and insert it into this object, which may be a significant amount of data. However, it can be useful to save the state of a particle collection at a certain point in time and reset this state later under certain conditions, for example if a timestep has to be undone and repeated.

Definition at line 152 of file particle_handler.cc.

## ◆ clear()

template<int dim, int spacedim>
 void Particles::ParticleHandler< dim, spacedim >::clear ( )

Clear all particle related data.

Definition at line 194 of file particle_handler.cc.

## ◆ clear_particles()

template<int dim, int spacedim>
 void Particles::ParticleHandler< dim, spacedim >::clear_particles ( )

Only clear particle data, but keep cache information about number of particles. This is useful during reorganization of particle data between processes.

Definition at line 206 of file particle_handler.cc.

## ◆ update_cached_numbers()

template<int dim, int spacedim>
 void Particles::ParticleHandler< dim, spacedim >::update_cached_numbers ( )

Update all internally cached numbers. Note that all functions that modify internal data structures and act on multiple particles will call this function automatically (e.g. insert_particles), while functions that act on single particles will not call this function (e.g. insert_particle). This is done because the update is expensive compared to single operations.

Definition at line 215 of file particle_handler.cc.

## ◆ begin() [1/2]

template<int dim, int spacedim>
 ParticleHandler< dim, spacedim >::particle_iterator Particles::ParticleHandler< dim, spacedim >::begin ( ) const

Return an iterator to the first particle.

Definition at line 269 of file particle_handler.cc.

## ◆ begin() [2/2]

template<int dim, int spacedim>
 ParticleHandler< dim, spacedim >::particle_iterator Particles::ParticleHandler< dim, spacedim >::begin ( )

Return an iterator to the first particle.

Definition at line 278 of file particle_handler.cc.

## ◆ end() [1/2]

template<int dim, int spacedim>
 ParticleHandler< dim, spacedim >::particle_iterator Particles::ParticleHandler< dim, spacedim >::end ( ) const

Return an iterator past the end of the particles.

Definition at line 287 of file particle_handler.cc.

## ◆ end() [2/2]

template<int dim, int spacedim>
 ParticleHandler< dim, spacedim >::particle_iterator Particles::ParticleHandler< dim, spacedim >::end ( )

Return an iterator past the end of the particles.

Definition at line 296 of file particle_handler.cc.

## ◆ begin_ghost() [1/2]

template<int dim, int spacedim>
 ParticleHandler< dim, spacedim >::particle_iterator Particles::ParticleHandler< dim, spacedim >::begin_ghost ( ) const

Return an iterator to the first ghost particle.

Definition at line 305 of file particle_handler.cc.

## ◆ begin_ghost() [2/2]

template<int dim, int spacedim>
 ParticleHandler< dim, spacedim >::particle_iterator Particles::ParticleHandler< dim, spacedim >::begin_ghost ( )

Return an iterator to the first ghost particle.

Definition at line 314 of file particle_handler.cc.

## ◆ end_ghost() [1/2]

template<int dim, int spacedim>
 ParticleHandler< dim, spacedim >::particle_iterator Particles::ParticleHandler< dim, spacedim >::end_ghost ( ) const

Return an iterator past the end of the ghost particles.

Definition at line 323 of file particle_handler.cc.

## ◆ end_ghost() [2/2]

template<int dim, int spacedim>
 ParticleHandler< dim, spacedim >::particle_iterator Particles::ParticleHandler< dim, spacedim >::end_ghost ( )

Return an iterator past the end of the ghost particles.

Definition at line 332 of file particle_handler.cc.

## ◆ n_particles_in_cell()

template<int dim, int spacedim>
 types::particle_index Particles::ParticleHandler< dim, spacedim >::n_particles_in_cell ( const typename Triangulation< dim, spacedim >::active_cell_iterator & cell ) const

Return the number of particles that live on the given cell.

Note
While this function is used in step-19, it is not an efficient function to use if the number of particles is large. That is because to find the particles that are located in one cell costs $${\cal O)(\log N)$$ where $$N$$ is the number of overall particles. Since you will likely do this for every cell, and assuming that the number of particles and the number of cells are roughly proportional, you end up with an $${\cal O)(N \log N)$$ algorithm. A better approach is to use the fact that internally, particles are arranged in the order of the active cells they are in. In other words, if you iterate over all particles, you will encounter them in the same order as you walk over the active cells. You can exploit this by keeping an iterator to the first particle of the first cell, and when you move to the next cell, you increment the particle iterator as well until you find a particle located on that next cell. Counting how many steps this took will then give you the number you are looking for, at a cost of $${\cal O)(\log N)$$ when accumulated over all cells. This is the approach used in step-70, for example. The approach is also detailed in the "Possibilities for extensions section" of step-19.

Definition at line 341 of file particle_handler.cc.

## ◆ particles_in_cell() [1/2]

template<int dim, int spacedim>
 ParticleHandler< dim, spacedim >::particle_iterator_range Particles::ParticleHandler< dim, spacedim >::particles_in_cell ( const typename Triangulation< dim, spacedim >::active_cell_iterator & cell )

Return a pair of particle iterators that mark the begin and end of the particles in a particular cell. The last iterator is the first particle that is no longer in the cell.

The number of elements in the returned range equals what the n_particles_in_cell() function returns.

Note
While this function is used in step-19, it is not an efficient function to use if the number of particles is large. That is because to find the particles that are located in one cell costs $${\cal O)(\log N)$$ where $$N$$ is the number of overall particles. Since you will likely do this for every cell, and assuming that the number of particles and the number of cells are roughly proportional, you end up with an $${\cal O)(N \log N)$$ algorithm. A better approach is to use the fact that internally, particles are arranged in the order of the active cells they are in. In other words, if you iterate over all particles, you will encounter them in the same order as you walk over the active cells. You can exploit this by keeping an iterator to the first particle of the first cell, and when you move to the next cell, you increment the particle iterator as well until you find a particle located on that next cell. This is the approach used in step-70, for example, and has an overall cost of $${\cal O)(\log N)$$ when accumulated over all cells. The approach is also detailed in the "Possibilities for extensions section" of step-19.

Definition at line 377 of file particle_handler.cc.

## ◆ particles_in_cell() [2/2]

template<int dim, int spacedim>
 ParticleHandler< dim, spacedim >::particle_iterator_range Particles::ParticleHandler< dim, spacedim >::particles_in_cell ( const typename Triangulation< dim, spacedim >::active_cell_iterator & cell ) const

Return a pair of particle iterators that mark the begin and end of the particles in a particular cell. The last iterator is the first particle that is no longer in the cell.

The number of elements in the returned range equals what the n_particles_in_cell() function returns.

Note
While this function is used in step-19, it is not an efficient function to use if the number of particles is large. That is because to find the particles that are located in one cell costs $${\cal O)(\log N)$$ where $$N$$ is the number of overall particles. Since you will likely do this for every cell, and assuming that the number of particles and the number of cells are roughly proportional, you end up with an $${\cal O)(N \log N)$$ algorithm. A better approach is to use the fact that internally, particles are arranged in the order of the active cells they are in. In other words, if you iterate over all particles, you will encounter them in the same order as you walk over the active cells. You can exploit this by keeping an iterator to the first particle of the first cell, and when you move to the next cell, you increment the particle iterator as well until you find a particle located on that next cell. This is the approach used in step-70, for example, and has an overall cost of $${\cal O)(\log N)$$ when accumulated over all cells. The approach is also detailed in the "Possibilities for extensions section" of step-19.

Definition at line 365 of file particle_handler.cc.

## ◆ remove_particle()

template<int dim, int spacedim = dim>
 void Particles::ParticleHandler< dim, spacedim >::remove_particle ( const particle_iterator & particle )

Remove a particle pointed to by the iterator.

Definition at line 410 of file particle_handler.cc.

## ◆ insert_particle()

template<int dim, int spacedim>
 ParticleHandler< dim, spacedim >::particle_iterator Particles::ParticleHandler< dim, spacedim >::insert_particle ( const Particle< dim, spacedim > & particle, const typename Triangulation< dim, spacedim >::active_cell_iterator & cell )

Insert a particle into the collection of particles. Return an iterator to the new position of the particle. This function involves a copy of the particle and its properties. Note that this function is of $$O(N \log N)$$ complexity for $$N$$ particles.

Definition at line 420 of file particle_handler.cc.

## ◆ insert_particles() [1/2]

template<int dim, int spacedim>
 void Particles::ParticleHandler< dim, spacedim >::insert_particles ( const std::multimap< typename Triangulation< dim, spacedim >::active_cell_iterator, Particle< dim, spacedim >> & particles )

Insert a number of particles into the collection of particles. This function involves a copy of the particles and their properties. Note that this function is of O(n_existing_particles + n_particles) complexity.

Definition at line 444 of file particle_handler.cc.

## ◆ insert_particles() [2/2]

template<int dim, int spacedim>
 void Particles::ParticleHandler< dim, spacedim >::insert_particles ( const std::vector< Point< spacedim >> & positions )

Create and insert a number of particles into the collection of particles. This function takes a list of positions and creates a set of particles at these positions, which are then added to the local particle collection. Note that this function currently uses GridTools::compute_point_locations(), which assumes all positions are within the local part of the triangulation. If one of them is not in the local domain this function will throw an exception.

Definition at line 469 of file particle_handler.cc.

## ◆ insert_global_particles() [1/2]

template<int dim, int spacedim>
 std::map< unsigned int, IndexSet > Particles::ParticleHandler< dim, spacedim >::insert_global_particles ( const std::vector< Point< spacedim >> & positions, const std::vector< std::vector< BoundingBox< spacedim >>> & global_bounding_boxes, const std::vector< std::vector< double >> & properties = {}, const std::vector< types::particle_index > & ids = {} )

Create and insert a number of particles into the collection of particles. This function takes a list of positions and creates a set of particles at these positions, which are then distributed and added to the local particle collection of a procesor. Note that this function uses GridTools::distributed_compute_point_locations(). Consequently, it can require intense communications between the processors. This function is used in step-70.

This function figures out what mpi process owns the points that do not fall within the locally owned part of the triangulation, it sends to that process the points passed to this function on this process, and receives the points that fall within the locally owned cells of the triangulation from whoever received them as input.

In order to keep track of what mpi process received what points, a map from mpi process to IndexSet is returned by the function. This IndexSet contains the local indices of the points that were passed to this function on the calling mpi process, and that falls within the part of triangulation owned by this mpi process.

The ids of the resulting particles are assigned from the optional argument ids. If the vector of ids is empty, then the ids are computed automatically from the get_next_free_particle_index() onward. For example, if the method get_next_free_particle_index() returns n0, calling this function with two MPI processes each adding n1 and n2 particles will result in the n1 particles added by process zero having ids equal to [n0,n0+n1), and the n2 particles added by process one having ids [n0+n1, n0+n1+n2).

Parameters
 [in] positions A vector of points that do not need to be on the local processor, but have to be in the triangulation that is associated with this ParticleHandler object. [in] global_bounding_boxes A vector of vectors of bounding boxes. The bounding boxes global_bboxes[rk] describe which part of the mesh is locally owned by the mpi process with rank rk. The local description can be obtained from GridTools::compute_mesh_predicate_bounding_box(), and the global one can be obtained by passing the local ones to Utilities::MPI::all_gather(). [in] properties (Optional) A vector of vector of properties associated with each local point. The size of the vector should be either zero (no properties will be transfered nor attached to the generated particles) or it should be a vector of positions.size() vectors of size n_properties_per_particle(). Notice that this function call will transfer the properties from the local mpi process to the final mpi process that will own each of the particles, and it may therefore be communication intensive. [in] ids (Optional) A vector of ids to associate to each particle. If the vector is empty, the ids are assigned as a continuous range from the first available index, as documented above. If the vector is not empty, then its size must match the size of the positions vector.
Returns
A map from owner to IndexSet, that contains the local indices of the points that were passed to this function on the calling mpi process, and that falls within the part of triangulation owned by this mpi process.

Definition at line 537 of file particle_handler.cc.

## ◆ insert_global_particles() [2/2]

template<int dim, int spacedim>
 std::map< unsigned int, IndexSet > Particles::ParticleHandler< dim, spacedim >::insert_global_particles ( const std::vector< Particle< dim, spacedim >> & particles, const std::vector< std::vector< BoundingBox< spacedim >>> & global_bounding_boxes )

Insert a number of particles into the collection of particles. This function takes a list of particles for which we don't know the associated cell iterator, and distributes them to the correct local particle collection of a procesor, by unpacking the locations, figuring out where to send the particles by calling GridTools::distributed_compute_point_locations(), and sending the particles to the corresponding process.

In order to keep track of what mpi process received what particles, a map from mpi process to IndexSet is returned by the function. This IndexSet contains the local indices of the particles that were passed to this function on the calling mpi process, and that falls within the part of the triangulation owned by this mpi process.

Parameters
 [in] particles A vector of particles that do not need to be on the local processor. [in] global_bounding_boxes A vector of vectors of bounding boxes. The bounding boxes global_bboxes[rk] describe which part of the mesh is locally owned by the mpi process with rank rk. The local description can be obtained from GridTools::compute_mesh_predicate_bounding_box(), and the global one can be obtained by passing the local ones to Utilities::MPI::all_gather().
Returns
A map from owner to IndexSet, that contains the local indices of the points that were passed to this function on the calling mpi process, and that falls within the part of triangulation owned by this mpi process.

Definition at line 778 of file particle_handler.cc.

## ◆ set_particle_positions() [1/3]

template<int dim, int spacedim>
template<class VectorType >
 std::enable_if< std::is_convertible< VectorType *, Function< spacedim > * >::value==false >::type Particles::ParticleHandler< dim, spacedim >::set_particle_positions ( const VectorType & input_vector, const bool displace_particles = true )

Set the position of the particles by using the values contained in the vector input_vector.

Template Parameters
 VectorType Any of the parallel distributed vectors supported by the library.

The vector input_vector should have read access to the indices created by extracting the locally relevant ids with locally_relevant_ids(), and taking its tensor product with the index set representing the range [0, spacedim), i.e.:

IndexSet ids = particle_handler.locally_relevant_ids().
tensor_product(complete_index_set(spacedim));

The position of the particle with global index id is read from spacedim consecutive entries starting from input_vector[id*spacedim].

Notice that it is not necessary that the input_vector owns those indices, however it has to have read access to them (i.e., it can be a distributed vector with ghost entries).

If the argument displace_particles is set to false, then the new position taken from the values contained in input_vector, replacing the previously stored particle position. By default, the particles are displaced by the amount contained in the input_vector, i.e., the contents of the vector are considered offsets that are added to the previous position.

After setting the new position, this function calls internally the method sort_particles_into_subdomains_and_cells(). You should make sure you satisfy the requirements of that function.

Parameters
 [in] input_vector A parallel distributed vector containing the displacement to apply to each particle, or their new absolute position. [in] displace_particles Control if the input_vector should be interpreted as a displacement vector, or a vector of absolute positions.

Definition at line 975 of file particle_handler.h.

## ◆ set_particle_positions() [2/3]

template<int dim, int spacedim>
 void Particles::ParticleHandler< dim, spacedim >::set_particle_positions ( const std::vector< Point< spacedim >> & new_positions, const bool displace_particles = true )

Set the position of the particles within the particle handler using a vector of points. The new set of point defined by the vector has to be sufficiently close to the original one to ensure that the sort_particles_into_subdomains_and_cells() function manages to find the new cells in which the particles belong.

Points are numbered in the same way they are traversed locally by the ParticleHandler. A typical way to use this method, is to first call the get_particle_positions() function, and then modify the resulting vector.

Parameters
 [in] new_positions A vector of points of dimension particle_handler.n_locally_owned_particles() [in] displace_particles When true, this function adds the value of the vector of points to the current position of the particle, thus displacing them by the amount given by the function. When false, the position of the particle is replaced by the value in the vector.

Definition at line 894 of file particle_handler.cc.

## ◆ set_particle_positions() [3/3]

template<int dim, int spacedim>
 void Particles::ParticleHandler< dim, spacedim >::set_particle_positions ( const Function< spacedim > & function, const bool displace_particles = true )

Set the position of the particles within the particle handler using a function with spacedim components. The new set of point defined by the fuction has to be sufficiently close to the original one to ensure that the sort_particles_into_subdomains_and_cells algorithm manages to find the new cells in which the particles belong.

The function is evaluated at the current location of the particles.

Parameters
 [in] function A function that has n_components==spacedim that describes either the displacement or the new position of the particles as a function of the current location of the particle. [in] displace_particles When true, this function adds the results of the function to the current position of the particle, thus displacing them by the amount given by the function. When false, the position of the particle is replaced by the value of the function.

Definition at line 916 of file particle_handler.cc.

## ◆ get_particle_positions() [1/2]

template<int dim, int spacedim>
template<class VectorType >
 void Particles::ParticleHandler< dim, spacedim >::get_particle_positions ( VectorType & output_vector, const bool add_to_output_vector = false )

Read the position of the particles and store them into the distributed vector output_vector. By default the output_vector is overwritten by this operation, but you can add to its entries by setting add_to_output_vector to true.

Template Parameters
 VectorType Any of the parallel distributed vectors supported by the library.

This is the reverse operation of the set_particle_positions() function. The position of the particle with global index id is written to spacedim consecutive entries starting from output_vector[id*spacedim].

Notice that, if you use a distributed vector type, it is not necessary for the output_vector to own the entries corresponding to the indices that will be written. However you should keep in mind that this requires a global communication to distribute the entries above to their respective owners.

Parameters
 [in,out] output_vector A parallel distributed vector containing the positions of the particles, or updated with the positions of the particles. [in] add_to_output_vector Control if the function should set the entries of the output_vector or if should add to them.

Definition at line 998 of file particle_handler.h.

## ◆ get_particle_positions() [2/2]

template<int dim, int spacedim>
 void Particles::ParticleHandler< dim, spacedim >::get_particle_positions ( std::vector< Point< spacedim >> & positions, const bool add_to_output_vector = false )

Gather the position of the particles within the particle handler in a vector of points. The order of the points is the same on would obtain by iterating over all (local) particles, and querying their locations.

Parameters
 [in,out] positions A vector preallocated at size particle_handler.n_locally_owned_articles and whose points will become the positions of the locally owned particles [in] add_to_output_vector When true, the value of the point of the particles is added to the positions vector. When false, the value of the points in the positions vector are replaced by the position of the particles.

Definition at line 873 of file particle_handler.cc.

template<int dim, int spacedim>
 void Particles::ParticleHandler< dim, spacedim >::register_additional_store_load_functions ( const std::function< std::size_t()> & size_callback, const std::function< void *(const particle_iterator &, void *)> & store_callback, const std::function< const void *(const particle_iterator &, const void *)> & load_callback )

This function allows to register three additional functions that are called every time a particle is transferred to another process (i.e. during sorting into cells, during ghost particle transfer, or during serialization of all particles).

Parameters
 size_callback A function that is called when serializing particle data. The function gets no arguments and is expected to return the size of the additional data that is serialized per particle. Note that this currently implies the data size has to be the same for every particle. store_callback A function that is called once per particle when serializing particle data. Arguments to the function are a particle iterator that identifies the current particle and a void pointer that points to a data block of size size_callback() in which the function can store additional data. The function is expected to return a void pointer pointing to a position right after its data block. load_callback A function that is called once per particle when deserializing particle data. Arguments to the function are a particle iterator that identifies the current particle and a void pointer that points to a data block of size size_callback() in which additional data was stored by the store_callback function. The function is expected to return a void pointer pointing to a position right after its data block.

Definition at line 1536 of file particle_handler.cc.

## ◆ n_global_particles()

template<int dim, int spacedim>
 types::particle_index Particles::ParticleHandler< dim, spacedim >::n_global_particles ( ) const

Return the total number of particles that were managed by this class the last time the update_cached_numbers() function was called. The actual number of particles may have changed since then if particles have been added or removed.

Returns
Total number of particles in simulation.

Definition at line 815 of file particle_handler.cc.

## ◆ n_global_max_particles_per_cell()

template<int dim, int spacedim>
 types::particle_index Particles::ParticleHandler< dim, spacedim >::n_global_max_particles_per_cell ( ) const

Return the maximum number of particles per cell the last time the update_cached_numbers() function was called.

Returns
Maximum number of particles in one cell in simulation.

Definition at line 824 of file particle_handler.cc.

## ◆ n_locally_owned_particles()

template<int dim, int spacedim>
 types::particle_index Particles::ParticleHandler< dim, spacedim >::n_locally_owned_particles ( ) const

Return the number of particles in the local part of the triangulation.

Definition at line 833 of file particle_handler.cc.

## ◆ get_next_free_particle_index()

template<int dim, int spacedim>
 types::particle_index Particles::ParticleHandler< dim, spacedim >::get_next_free_particle_index ( ) const

Return the next free particle index in the global set of particles the last time the update_cached_numbers() function was called.

Definition at line 851 of file particle_handler.cc.

## ◆ locally_relevant_ids()

template<int dim, int spacedim>
 IndexSet Particles::ParticleHandler< dim, spacedim >::locally_relevant_ids ( ) const

Extract an IndexSet with global dimensions equal to get_next_free_particle_index(), containing the locally owned particle indices.

This function can be used to construct distributed vectors and matrices to manipulate particles using linear algebra operations.

Notice that it is the user's responsibility to guarantee that particle indices are unique, and no check is performed to verify that this is the case, nor that the union of all IndexSet objects on each mpi process is complete.

Returns
An IndexSet of size get_next_free_particle_index(), containing n_locally_owned_particle() indices.

Definition at line 860 of file particle_handler.cc.

## ◆ n_properties_per_particle()

template<int dim, int spacedim>
 unsigned int Particles::ParticleHandler< dim, spacedim >::n_properties_per_particle ( ) const

Return the number of properties each particle has.

Definition at line 842 of file particle_handler.cc.

## ◆ get_property_pool()

template<int dim, int spacedim>
 PropertyPool & Particles::ParticleHandler< dim, spacedim >::get_property_pool ( ) const

Return a reference to the property pool that owns all particle properties, and organizes them physically.

Definition at line 944 of file particle_handler.cc.

## ◆ sort_particles_into_subdomains_and_cells()

template<int dim, int spacedim>
 void Particles::ParticleHandler< dim, spacedim >::sort_particles_into_subdomains_and_cells ( )

Find and update the cells containing each particle for all locally owned particles. If particles moved out of the local subdomain they will be sent to their new process and inserted there. After this function call every particle is either on its current process and in its current cell, or deleted (if it could not find its new process or cell).

The user may attach a function to the signal Particles::ParticleHandler::Signals::particle_lost(). The signal is triggered whenever a particle is deleted, and the connected functions are called passing an iterator to the particle in question, and its last known cell association.

Definition at line 984 of file particle_handler.cc.

## ◆ exchange_ghost_particles()

template<int dim, int spacedim>
 void Particles::ParticleHandler< dim, spacedim >::exchange_ghost_particles ( )

Exchange all particles that live in cells that are ghost cells to other processes. Clears and re-populates the ghost_neighbors member variable.

Definition at line 1224 of file particle_handler.cc.

## ◆ register_store_callback_function()

template<int dim, int spacedim>
 void Particles::ParticleHandler< dim, spacedim >::register_store_callback_function ( )

Callback function that should be called before every refinement and when writing checkpoints. This function is used to register store_particles() with the triangulation. This function is used in step-70.

Definition at line 1551 of file particle_handler.cc.

template<int dim, int spacedim>
 void Particles::ParticleHandler< dim, spacedim >::register_load_callback_function ( const bool serialization )

Callback function that should be called after every refinement and after resuming from a checkpoint. This function is used to register load_particles() with the triangulation. This function is used in step-70.

Definition at line 1588 of file particle_handler.cc.

## ◆ serialize()

template<int dim, int spacedim>
template<class Archive >
 void Particles::ParticleHandler< dim, spacedim >::serialize ( Archive & ar, const unsigned int version )

Serialize the contents of this class.

Definition at line 957 of file particle_handler.h.

## ◆ send_recv_particles()

template<int dim, int spacedim>
 void Particles::ParticleHandler< dim, spacedim >::send_recv_particles ( const std::map< types::subdomain_id, std::vector< particle_iterator >> & particles_to_send, std::multimap< internal::LevelInd, Particle< dim, spacedim >> & received_particles, const std::map< types::subdomain_id, std::vector< typename Triangulation< dim, spacedim >::active_cell_iterator >> & new_cells_for_particles = std::map< types::subdomain_id, std::vector< typename Triangulation::active_cell_iterator>>() )
private

Transfer particles that have crossed subdomain boundaries to other processors. All received particles and their new cells will be appended to the received_particles vector.

Parameters
 [in] particles_to_send All particles that should be sent and their new subdomain_ids are in this map. [in,out] received_particles Vector that stores all received particles. Note that it is not required nor checked that the list is empty, received particles are simply attached to the end of the vector. [in] new_cells_for_particles Optional vector of cell iterators with the same structure as particles_to_send. If this parameter is given it should contain the cell iterator for every particle to be send in which the particle belongs. This parameter is necessary if the cell information of the particle iterator is outdated (e.g. after particle movement).

Definition at line 1302 of file particle_handler.cc.

## ◆ store_particles()

template<int dim, int spacedim>
 std::vector< char > Particles::ParticleHandler< dim, spacedim >::store_particles ( const typename Triangulation< dim, spacedim >::cell_iterator & cell, const typename Triangulation< dim, spacedim >::CellStatus status ) const
private

Called by listener functions from Triangulation for every cell before a refinement step. All particles have to be attached to their cell to be sent around to the new processes.

Definition at line 1653 of file particle_handler.cc.

template<int dim, int spacedim>
 void Particles::ParticleHandler< dim, spacedim >::load_particles ( const typename Triangulation< dim, spacedim >::cell_iterator & cell, const typename Triangulation< dim, spacedim >::CellStatus status, const boost::iterator_range< std::vector< char >::const_iterator > & data_range )
private

Called by listener functions after a refinement step. The local map of particles has to be read from the triangulation user_pointer.

Definition at line 1744 of file particle_handler.cc.

## ◆ subscribe()

 void Subscriptor::subscribe ( std::atomic< bool > *const validity, const std::string & identifier = "" ) const
inherited

Subscribes a user of the object by storing the pointer validity. The subscriber may be identified by text supplied as identifier.

Definition at line 136 of file subscriptor.cc.

## ◆ unsubscribe()

 void Subscriptor::unsubscribe ( std::atomic< bool > *const validity, const std::string & identifier = "" ) const
inherited

Unsubscribes a user from the object.

Note
The identifier and the validity pointer must be the same as the one supplied to subscribe().

Definition at line 156 of file subscriptor.cc.

## ◆ n_subscriptions()

 unsigned int Subscriptor::n_subscriptions ( ) const
inlineinherited

Return the present number of subscriptions to this object. This allows to use this class for reference counted lifetime determination where the last one to unsubscribe also deletes the object.

Definition at line 300 of file subscriptor.h.

## ◆ list_subscribers() [1/2]

template<typename StreamType >
 void Subscriptor::list_subscribers ( StreamType & stream ) const
inlineinherited

List the subscribers to the input stream.

Definition at line 317 of file subscriptor.h.

## ◆ list_subscribers() [2/2]

 void Subscriptor::list_subscribers ( ) const
inherited

List the subscribers to deallog.

Definition at line 204 of file subscriptor.cc.

## ◆ signals

template<int dim, int spacedim = dim>
 Signals Particles::ParticleHandler< dim, spacedim >::signals
mutable

Signals for the events that a particle handler can notify the calling application about.

Definition at line 773 of file particle_handler.h.

## ◆ triangulation

template<int dim, int spacedim = dim>
 SmartPointer, ParticleHandler > Particles::ParticleHandler< dim, spacedim >::triangulation
private

Address of the triangulation to work on.

Definition at line 781 of file particle_handler.h.

## ◆ mapping

template<int dim, int spacedim = dim>
 SmartPointer, ParticleHandler > Particles::ParticleHandler< dim, spacedim >::mapping
private

Address of the mapping to work on.

Definition at line 787 of file particle_handler.h.

## ◆ particles

template<int dim, int spacedim = dim>
 std::multimap > Particles::ParticleHandler< dim, spacedim >::particles
private

Set of particles currently living in the local domain, organized by the level/index of the cell they are in.

Definition at line 793 of file particle_handler.h.

## ◆ ghost_particles

template<int dim, int spacedim = dim>
 std::multimap > Particles::ParticleHandler< dim, spacedim >::ghost_particles
private

Set of particles that currently live in the ghost cells of the local domain, organized by the level/index of the cell they are in. These particles are equivalent to the ghost entries in distributed vectors.

Definition at line 800 of file particle_handler.h.

## ◆ global_number_of_particles

template<int dim, int spacedim = dim>
 types::particle_index Particles::ParticleHandler< dim, spacedim >::global_number_of_particles
private

This variable stores how many particles are stored globally. It is calculated by update_cached_numbers().

Definition at line 806 of file particle_handler.h.

## ◆ global_max_particles_per_cell

template<int dim, int spacedim = dim>
 unsigned int Particles::ParticleHandler< dim, spacedim >::global_max_particles_per_cell
private

The maximum number of particles per cell in the global domain. This variable is important to store and load particle data during repartition and serialization of the solution. Note that the variable is only updated when it is needed, e.g. after particle movement, before/after mesh refinement, before creating a checkpoint and after resuming from a checkpoint.

Definition at line 816 of file particle_handler.h.

## ◆ next_free_particle_index

template<int dim, int spacedim = dim>
 types::particle_index Particles::ParticleHandler< dim, spacedim >::next_free_particle_index
private

This variable stores the next free particle index that is available globally in case new particles need to be generated.

Definition at line 822 of file particle_handler.h.

## ◆ property_pool

template<int dim, int spacedim = dim>
 std::unique_ptr Particles::ParticleHandler< dim, spacedim >::property_pool
private

This object owns and organizes the memory for all particle properties.

Definition at line 828 of file particle_handler.h.

## ◆ size_callback

template<int dim, int spacedim = dim>
 std::function Particles::ParticleHandler< dim, spacedim >::size_callback
private

A function that can be registered by calling register_additional_store_load_functions. It is called when serializing particle data. The function gets no arguments and is expected to return the size of the additional data that is serialized per particle. Note that this currently implies the data size has to be the same for every particle, but it does not have to be the same for every serialization process (e.g. a serialization during particle movement might include temporary data, while a serialization after movement was finished does not need to transfer this data).

Definition at line 841 of file particle_handler.h.

## ◆ store_callback

template<int dim, int spacedim = dim>
 std::function Particles::ParticleHandler< dim, spacedim >::store_callback
private

A function that can be registered by calling register_additional_store_load_functions. It is called once per particle when serializing particle data. Arguments to the function are a particle iterator that identifies the current particle and a void pointer that points to a data block of size size_callback() in which the function can store additional data. The function is expected to return a void pointer pointing to a position right after its data block.

Definition at line 853 of file particle_handler.h.

template<int dim, int spacedim = dim>
private

A function that is called once per particle when deserializing particle data. Arguments to the function are a particle iterator that identifies the current particle and a void pointer that points to a data block of size size_callback() from which the function can load additional data. This block was filled by the store_callback function during serialization. This function is expected to return a void pointer pointing to a position right after its data block.

Definition at line 866 of file particle_handler.h.

## ◆ handle

template<int dim, int spacedim = dim>
 unsigned int Particles::ParticleHandler< dim, spacedim >::handle
private

This variable is set by the register_store_callback_function() function and used by the register_load_callback_function() function to check where the particle data was registered in the corresponding triangulation object.

Definition at line 874 of file particle_handler.h.

## ◆ triangulation_cache

template<int dim, int spacedim = dim>
 std::unique_ptr > Particles::ParticleHandler< dim, spacedim >::triangulation_cache
private

The GridTools::Cache is used to store the information about the vertex_to_cells set and the vertex_to_cell_centers vectors to prevent recomputing them every time we sort_into_subdomain_and_cells(). This cache is automatically updated when the triangulation has changed. This cache is stored within a unique pointer because the particle handler has a constructor that enables it to be constructed without a triangulation. The cache does not have such a constructor.

Definition at line 885 of file particle_handler.h.

The documentation for this class was generated from the following files: