gko::experimental::distributed::index_map< LocalIndexType, GlobalIndexType > Class Template Reference

This class defines mappings between global and local indices. More...

#include <ginkgo/core/distributed/index_map.hpp>

Public Types
using	partition_type = Partition< LocalIndexType, GlobalIndexType >

Public Member Functions
array< LocalIndexType >	map_to_local (const array< GlobalIndexType > &global_ids, index_space index_space_v) const
	Maps global indices to local indices.
array< GlobalIndexType >	map_to_global (const array< LocalIndexType > &local_idxs, index_space index_space_v) const
size_type	get_global_size () const
	get size of index_space::local
size_type	get_local_size () const
	get size of index_space::local
size_type	get_non_local_size () const
	get size of index_space::non_local
	index_map (std::shared_ptr< const Executor > exec, std::shared_ptr< const partition_type > partition, comm_index_type rank, const array< GlobalIndexType > &recv_connections)
	Creates a new index map.
	index_map (std::shared_ptr< const Executor > exec)
	Creates an empty index map.
const segmented_array< GlobalIndexType > &	get_remote_global_idxs () const
	get the index set \(R_k\) for this rank.
const segmented_array< LocalIndexType > &	get_remote_local_idxs () const
	get the index set \(R_k\), but mapped to their respective local index space.
const array< comm_index_type > &	get_remote_target_ids () const
	get the rank ids which contain indices accessed by this rank.
std::shared_ptr< const Executor >	get_executor () const
	get the associated executor.
	index_map (const index_map &other)
	index_map (index_map &&other) noexcept
index_map &	operator= (const index_map &other)
index_map &	operator= (index_map &&other)

Detailed Description

template<typename LocalIndexType, typename GlobalIndexType = int64>
class gko::experimental::distributed::index_map< LocalIndexType, GlobalIndexType >

This class defines mappings between global and local indices.

Given an index space \(I = [0, \dots, N)\) that is partitioned into \(P\) disjoint subsets \(I_k, k = 1, \dots, P\), this class defines for each subset an extended global index set \(\hat{I}_k \supset I_K\). The extended index set contains the global indices owned by part \(k\), as well as remote indices \(R_k = \hat{I}_k \setminus I_k\), which are also accessed by part \(k\), but owned by parts \(l \neq k\). At the core, this class provides mappings from the global index space \(I\) into different local index spaces. The combined local index space (index_space::combined) is then defined as \([0, \dots, |\hat{I}_k|)\). Additionally, the combined index space can be separated into locally owned (index_space::local) and non-locally owned (index_space::non_local). The locally owned indices are defined as \([0, \dots, |I_k|)\), and the non-locally owned as \([0, \dots, |R_k|)\). With these index sets, the following mappings are defined:

• \(c_k : \hat{I}_k \mapsto [0, \dots, |\hat{I}_k|)\) which maps global indices into the combined/full local index space (denoted as index_space::combined),
• \(l_k: I_k \mapsto [0, \dots, |I_k|)\) which maps global indices into the locally owned index space (denoted as index_space::local),
• \(r_k: R_k \mapsto [0, \dots, |R_k|)\) which maps global indices into the non-locally owned index space (denoted as index_space::non_local).

The required map can be selected by passing the appropriate type of an index_space.

The index map for \(I_k\) has no knowledge about any other index maps for \(I_l, l \neq k\). In particular, any global index passed to the map_to_local map that is not part of the specified index space, will be mapped to an invalid_index.

Template Parameters

LocalIndexType	type for local indices
GlobalIndexType	type for global indices

Constructor & Destructor Documentation

index_map()

template<typename LocalIndexType , typename GlobalIndexType = int64>

gko::experimental::distributed::index_map< LocalIndexType, GlobalIndexType >::index_map	(	std::shared_ptr< const Executor >	exec,
		std::shared_ptr< const partition_type >	partition,
		comm_index_type	rank,
		const array< GlobalIndexType > &	recv_connections
	)

Creates a new index map.

The passed in recv_connections may contain duplicates, which will be filtered out.

Parameters

exec	the executor
partition	the partition of the global index set
rank	the id of the global index space subset
recv_connections	the global indices that are not owned by this rank, but accessed by it

Member Function Documentation

get_remote_global_idxs()

template<typename LocalIndexType , typename GlobalIndexType = int64>

const segmented_array< GlobalIndexType > & gko::experimental::distributed::index_map< LocalIndexType, GlobalIndexType >::get_remote_global_idxs

(

)

const

get the index set \(R_k\) for this rank.

The indices are ordered by their owning rank and global index.

get_remote_local_idxs()

template<typename LocalIndexType , typename GlobalIndexType = int64>

const segmented_array< LocalIndexType > & gko::experimental::distributed::index_map< LocalIndexType, GlobalIndexType >::get_remote_local_idxs

(

)

const

get the index set \(R_k\), but mapped to their respective local index space.

The indices are grouped by their owning rank and sorted according to their global index within each group.

The set \(R_k = \hat{I}_k \setminus I_k\) can also be written as the union of the intersection of \(\hat{I}_k\) with other disjoint sets \(I_l, l \neq k\), i.e. \(R_k = \bigcup_{j \neq k} \hat{I}_k \cap I_j = \bigcup_{j \neq k} R_{k,j}\). The set \(R_{k,j}\) can then be mapped by \(l_j\) to get the local indices wrt. part \(j\). The indices here are mapped by \(l_j\).

get_remote_target_ids()

template<typename LocalIndexType , typename GlobalIndexType = int64>

const array< comm_index_type > & gko::experimental::distributed::index_map< LocalIndexType, GlobalIndexType >::get_remote_target_ids

(

)

const

get the rank ids which contain indices accessed by this rank.

The order matches the order of the sets in get_remote_global_idxs and get_remote_local_idxs.

map_to_global()

template<typename LocalIndexType , typename GlobalIndexType = int64>

array< GlobalIndexType > gko::experimental::distributed::index_map< LocalIndexType, GlobalIndexType >::map_to_global	(	const array< LocalIndexType > &	local_idxs,
		index_space	index_space_v
	)		const

Maps local indices to global indices

Parameters

local_idxs	the local indices to map
index_space_v	the index space in which the passed-in local indices are defined

Returns

the mapped global indices. Any local index, that is not in the specified index space is mapped to invalid_index

map_to_local()

template<typename LocalIndexType , typename GlobalIndexType = int64>

array< LocalIndexType > gko::experimental::distributed::index_map< LocalIndexType, GlobalIndexType >::map_to_local	(	const array< GlobalIndexType > &	global_ids,
		index_space	index_space_v
	)		const

Maps global indices to local indices.

Parameters

global_ids	the global indices to map
index_space_v	the index space in which the returned local indices are defined

Returns

the mapped local indices. Any global index that is not in the specified index space is mapped to invalid_index.

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

• ginkgo/core/distributed/index_map.hpp