Distributed property map adaptor. More...

#include <distributed_property_map.hpp>

Inheritance diagram for boost::parallel::distributed_property_map< ProcessGroup, GlobalMap, StorageMap >:

Collaboration diagram for boost::parallel::distributed_property_map< ProcessGroup, GlobalMap, StorageMap >:

Classes
struct	data_t

Public Types
typedef property_traits < GlobalMap >::key_type	key_type
	The key type of the property map. More...

typedef property_traits < StorageMap >::value_type	value_type
	The value type of the property map. More...

typedef property_traits < StorageMap >::reference	reference

typedef ProcessGroup	process_group_type

typedef multi_index::multi_index_container < std::pair< key_type, value_type > , multi_index::indexed_by < multi_index::sequenced <>, multi_index::hashed_unique < pair_first_extractor < key_type, value_type > > > >	ghost_cells_type
	The type of the ghost cells. More...

typedef ghost_cells_type::iterator	iterator
	Iterator into the ghost cells. More...

typedef ghost_cells_type::template nth_index< 1 >::type	ghost_cells_key_index_type
	Key-based index into the ghost cells. More...

typedef ghost_cells_key_index_type::iterator	key_iterator
	Iterator into the ghost cells (by key) More...

typedef detail::make_nonlvalue_property_map < (is_base_and_derived < lvalue_property_map_tag, local_category >::value\|\|is_same < lvalue_property_map_tag, local_category >::value)> ::template apply < local_category >::type	category
	The property map category. More...

Public Member Functions
	distributed_property_map ()
	Default-construct a distributed property map. More...

	distributed_property_map (const ProcessGroup &pg, const GlobalMap &global, const StorageMap &pm)
	Construct a distributed property map. More...

template<typename Reduce >
	distributed_property_map (const ProcessGroup &pg, const GlobalMap &global, const StorageMap &pm, const Reduce &reduce)
	Construct a distributed property map. More...

	~distributed_property_map ()

template<typename Reduce >
void	set_reduce (const Reduce &reduce)
	Set the reduce operation of the distributed property map. More...

void	set_consistency_model (int model)

int	get_consistency_model () const

void	set_max_ghost_cells (std::size_t max_ghost_cells)

void	clear ()

void	reset ()

void	flush ()

reference	operator[] (const key_type &key) const

process_group_type	process_group () const

StorageMap &	base ()

const StorageMap &	base () const

void	request_put (process_id_type p, const key_type &k, const value_type &v) const
	Sends a "put" request. More...

value_type &	cell (const key_type &k, bool request_if_missing=true) const
	Access the ghost cell for the given key. More...

void	do_synchronize ()
	Perform synchronization. More...

const GlobalMap &	global () const

GlobalMap &	global ()

Public Attributes
shared_ptr< data_t >	data

Friends
struct	data_t

Detailed Description

template<typename ProcessGroup, typename GlobalMap, typename StorageMap>
class boost::parallel::distributed_property_map< ProcessGroup, GlobalMap, StorageMap >

Distributed property map adaptor.

The distributed property map adaptor is a property map whose stored values are distributed across multiple non-overlapping memory spaces on different processes. Values local to the current process are stored within a local property map and may be immediately accessed via get and put. Values stored on remote processes may also be access via get and put, but the behavior differs slightly:

put operations update a local ghost cell and send a "put" message to the process that owns the value. The owner is free to update its own "official" value or may ignore the put request.
get operations returns the contents of the local ghost cell. If no ghost cell is available, one is created using the default value provided by the "reduce" operation. See, e.g., basic_reduce and property_reduce.

Using distributed property maps requires a bit more care than using local, sequential property maps. While the syntax and semantics are similar, distributed property maps may contain out-of-date information that can only be guaranteed to be synchronized by calling the synchronize function in all processes.

To address the issue of out-of-date values, distributed property maps are supplied with a reduction operation. The reduction operation has two roles:

When a value is needed for a remote key but no value is immediately available, the reduction operation provides a suitable default. For instance, a distributed property map storing distances may have a reduction operation that returns an infinite value as the default, whereas a distributed property map for vertex colors may return white as the default.
When a value is received from a remote process, the process owning the key associated with that value must determine which value—the locally stored value, the value received from a remote process, or some combination of the two—will be stored as the "official" value in the property map. The reduction operation transforms the local and remote values into the "official" value to be stored.

Template Parameters

ProcessGroup the type of the process group over which the property map is distributed and is also the medium for communication.

StorageMap the type of the property map that will store values for keys local to this processor. The value_type of this property map will become the value_type of the distributed property map. The distributed property map models the same property map concepts as the LocalPropertyMap, with one exception: a distributed property map cannot be an LvaluePropertyMap (because remote values are not addressable), and is therefore limited to ReadWritePropertyMap.