t8_cmesh_offset.h File Reference

In this file we collect function that deal with the cmesh partition offset. More...

#include <t8.h>
#include <t8_cmesh.h>

Go to the source code of this file.

Functions
t8_gloidx_t	t8_offset_first (int proc, const t8_gloidx_t *offset)
	Return the global id of the first local tree of a given process in a partition. More...
t8_gloidx_t	t8_offset_first_tree_to_entry (t8_gloidx_t first_tree, int shared)
	Given the global tree id of the first local tree of a process and the flag whether it is shared or not, compute the entry in the offset array. More...
t8_gloidx_t	t8_offset_num_trees (int proc, const t8_gloidx_t *offset)
	The number of trees of a given process in a partition. More...
t8_gloidx_t	t8_offset_last (int proc, const t8_gloidx_t *offset)
	Return the last local tree of a given process in a partition. More...
int	t8_offset_empty (int proc, const t8_gloidx_t *offset)
	Check whether a given process has no local trees in a given partition. More...
int	t8_offset_next_nonempty_rank (int rank, int mpisize, const t8_gloidx_t *offset)
	Find the next higher rank that is not empty. More...
int	t8_offset_in_range (t8_gloidx_t tree_id, int proc, const t8_gloidx_t *offset)
	Determine whether a given global tree id is a local tree of a given process in a certain partition. More...
int	t8_offset_any_owner_of_tree (int mpisize, t8_gloidx_t gtree, const t8_gloidx_t *offset)
	Find any process that has a given tree as local tree. More...
int	t8_offset_first_owner_of_tree (int mpisize, t8_gloidx_t gtree, const t8_gloidx_t *offset, int *some_owner)
	Find the smallest process that has a given tree as local tree. More...
int	t8_offset_last_owner_of_tree (int mpisize, t8_gloidx_t gtree, const t8_gloidx_t *offset, int *some_owner)
	Find the biggest process that has a given tree as local tree. More...
int	t8_offset_next_owner_of_tree (int mpisize, t8_gloidx_t gtree, const t8_gloidx_t *offset, int current_owner)
	Given a process current_owner that has the tree gtree as local tree, find the next bigger rank that also has this tree as local tree. More...
int	t8_offset_prev_owner_of_tree (int mpisize, t8_gloidx_t gtree, const t8_gloidx_t *offset, int current_owner)
	Given a process current_owner that has the tree gtree as local tree, find the next smaller rank that also has this tree as local tree. More...
void	t8_offset_all_owners_of_tree (int mpisize, t8_gloidx_t gtree, const t8_gloidx_t *offset, sc_array_t *owners)
	Compute a list of all processes that own a specific tree.n offset minus 1. More...
int	t8_offset_nosend (int proc, int mpisize, const t8_gloidx_t *offset_from, const t8_gloidx_t *offset_to)
	Query whether in a repartition setting a given process does send any of its local trees to any other process (including itself) More...
int	t8_offset_sendsto (int proca, int procb, const t8_gloidx_t *t8_offset_from, const t8_gloidx_t *t8_offset_to)
	Query whether in a repartitioning setting, a given process sends local trees (and then possibly ghosts) to a given other process. More...
int	t8_offset_sendstree (int proc_send, int proc_to, t8_gloidx_t gtree, const t8_gloidx_t *offset_from, const t8_gloidx_t *offset_to)
	Query whether in a repartitioning setting, a given process sends a given tree to a second process. More...
int	t8_offset_range_send (int start, int end, int mpirank, const t8_gloidx_t *offset_from, const t8_gloidx_t *offset_to)
	Count the number of processes in a given range [a,b] that send to a given other process in a repartitioning setting. More...
void	t8_offset_print (t8_shmem_array_t offset, sc_MPI_Comm comm)
	Print an offset array. More...

Detailed Description

In this file we collect function that deal with the cmesh partition offset.

TODO: document this file

Function Documentation

t8_offset_all_owners_of_tree()

void t8_offset_all_owners_of_tree	(	int	mpisize,
		t8_gloidx_t	gtree,
		const t8_gloidx_t *	offset,
		sc_array_t *	owners
	)

Compute a list of all processes that own a specific tree.n offset minus 1.

Parameters

[in]	mpisize	The number of MPI ranks, also the number of entries in offset minus 1.
[in]	gtree	The global index of a tree.
[in]	offset	The partition to be considered.
[in,out]	owners	On input an initialized sc_array with integer entries and zero elements. On output a sorted list of all MPI ranks that have gtree as a local tree in offset.

t8_offset_any_owner_of_tree()

int t8_offset_any_owner_of_tree	(	int	mpisize,
		t8_gloidx_t	gtree,
		const t8_gloidx_t *	offset
	)

Find any process that has a given tree as local tree.

Parameters

[in]	mpisize	The number of MPI ranks, also the number of entries in offset minus 1.
[in]	gtree	The global id of a tree.
[in]	offset	The partition to be considered.

Returns

An MPI rank that has gtree as a local tree.

t8_offset_empty()

int t8_offset_empty	(	int	proc,
		const t8_gloidx_t *	offset
	)

Check whether a given process has no local trees in a given partition.

Parameters

[in]	proc	A mpi rank.
[in]	offset	A partition table.

Returns

nonzero if proc does not have local trees in offset. 0 otherwise.

t8_offset_first()

t8_gloidx_t t8_offset_first	(	int	proc,
		const t8_gloidx_t *	offset
	)

Return the global id of the first local tree of a given process in a partition.

Parameters

[in]	proc	The rank of the process.
[in]	offset	The partition table.

Returns

The global id of the first local tree of proc in the partition offset.

t8_offset_first_owner_of_tree()

int t8_offset_first_owner_of_tree	(	int	mpisize,
		t8_gloidx_t	gtree,
		const t8_gloidx_t *	offset,
		int *	some_owner
	)

Find the smallest process that has a given tree as local tree.

To increase the runtime, an arbitrary process having this tree as local tree can be passed as an argument. Otherwise, such an owner is computed during the call.

Parameters

[in]	mpisize	The number of MPI ranks, also the number of entries in offset minus 1.
[in]	gtree	The global id of a tree.
[in]	offset	The partition to be considered.
[in]	some_owner	If >= 0 considered as input: a process that has gtree as local tree. If < 0 on output a process that has gtree as local tree. Specifying some_owner increases the runtime from O(log mpisize) to O(n), where n is the number of owners of the tree.

Returns

The smallest rank that has gtree as a local tree.

t8_offset_first_tree_to_entry()

t8_gloidx_t t8_offset_first_tree_to_entry	(	t8_gloidx_t	first_tree,
		int	shared
	)

Given the global tree id of the first local tree of a process and the flag whether it is shared or not, compute the entry in the offset array.

This entry is the first_tree if it is not shared and -first_tree - 1 if it is shared.

Parameters

[in]	first_tree	The global tree id of a process's first tree.
[in]	shared	0 if first_tree is not shared with a smaller rank, 1 if it is.

Returns

The entry that represents the process in an offset array. first_tree if shared == 0

• first_tree - 1 if shared != 0

t8_offset_in_range()

int t8_offset_in_range	(	t8_gloidx_t	tree_id,
		int	proc,
		const t8_gloidx_t *	offset
	)

Determine whether a given global tree id is a local tree of a given process in a certain partition.

Parameters

[in]	tree_id	A global tree id.
[in]	proc	A mpi rank.
[in]	offset	A partition table.

Returns

nonzero if tree_id is a local tree of proc in offset. 0 if it is not.

t8_offset_last()

t8_gloidx_t t8_offset_last	(	int	proc,
		const t8_gloidx_t *	offset
	)

Return the last local tree of a given process in a partition.

Parameters

[in]	proc	A mpi rank.
[in]	offset	A partition table.

Returns

The global tree id of the last local tree of proc in offset.

t8_offset_last_owner_of_tree()

int t8_offset_last_owner_of_tree	(	int	mpisize,
		t8_gloidx_t	gtree,
		const t8_gloidx_t *	offset,
		int *	some_owner
	)

Find the biggest process that has a given tree as local tree.

To increase the runtime, an arbitrary process having this tree as local tree can be passed as an argument. Otherwise, such an owner is computed during the call.

Parameters

[in]	mpisize	The number of MPI ranks, also the number of entries in offset minus 1.
[in]	gtree	The global id of a tree.
[in]	offset	The partition to be considered.
[in,out]	some_owner	If >= 0 considered as input: a process that has gtree as local tree. If < 0 on output a process that has gtree as local tree. Specifying some_owner increases the runtime from O(log mpisize) to O(n), where n is the number of owners of the tree.

Returns

The biggest rank that has gtree as a local tree.

t8_offset_next_nonempty_rank()

int t8_offset_next_nonempty_rank	(	int	rank,
		int	mpisize,
		const t8_gloidx_t *	offset
	)

Find the next higher rank that is not empty.

returns mpisize if this rank does not exist.

Parameters

[in]	proc	An MPI rank.
[in]	mpisize	The number of total MPI ranks.
[in]	offset	An array with at least mpisize + 1 entries.

Returns

A rank p such that p > rank and t8_offset_empty (p, offset) is True and t8_offset_empty (q, offset) is False for all rank < q < p. If no such q exists, mpisize is returned.

t8_offset_next_owner_of_tree()

int t8_offset_next_owner_of_tree	(	int	mpisize,
		t8_gloidx_t	gtree,
		const t8_gloidx_t *	offset,
		int	current_owner
	)

Given a process current_owner that has the tree gtree as local tree, find the next bigger rank that also has this tree as local tree.

Parameters

[in]	mpisize	The number of MPI ranks, also the number of entries in offset minus 1.
[in]	gtree	The global id of a tree.
[in]	offset	The partition to be considered.
[in]	current_owner	A process that has gtree as local tree.

Returns

The MPI rank of the next bigger rank than current_owner that has gtree as local tree. -1 if non such rank exists.

t8_offset_nosend()

int t8_offset_nosend	(	int	proc,
		int	mpisize,
		const t8_gloidx_t *	offset_from,
		const t8_gloidx_t *	offset_to
	)

Query whether in a repartition setting a given process does send any of its local trees to any other process (including itself)

Parameters

[in]	proc	A mpi rank.
[in]	mpisize	The number of MPI ranks, also the number of entries in offset minus 1.
[in]	offset_from	The partition table of the current partition.
[in]	offset_to	The partition table of the next partition.

Returns

nonzero if proc will not send any local trees if we repartition from offset_from to offset_to 0 if it does send local trees.

t8_offset_num_trees()

t8_gloidx_t t8_offset_num_trees	(	int	proc,
		const t8_gloidx_t *	offset
	)

The number of trees of a given process in a partition.

Parameters

[in]	proc	A mpi rank.
[in]	offset	A partition table.

Returns

The number of local trees of proc in the partition offset.

t8_offset_prev_owner_of_tree()

int t8_offset_prev_owner_of_tree	(	int	mpisize,
		t8_gloidx_t	gtree,
		const t8_gloidx_t *	offset,
		int	current_owner
	)

Given a process current_owner that has the tree gtree as local tree, find the next smaller rank that also has this tree as local tree.

Parameters

[in]	mpisize	The number of MPI ranks, also the number of entries in offset minus 1.
[in]	gtree	The global id of a tree.
[in]	offset	The partition to be considered.
[in]	current_owner	A process that has gtree as local tree.

Returns

The MPI rank of the next smaller rank than current_owner that has gtree as local tree. -1 if non such rank exists.

t8_offset_print()

void t8_offset_print	(	t8_shmem_array_t	offset,
		sc_MPI_Comm	comm
	)

Print an offset array.

Useful for debugging.

Parameters

[in]	offset	The offset to print
[in]	comm	An mpi communicator matching the offset size.

t8_offset_range_send()

int t8_offset_range_send	(	int	start,
		int	end,
		int	mpirank,
		const t8_gloidx_t *	offset_from,
		const t8_gloidx_t *	offset_to
	)

Count the number of processes in a given range [a,b] that send to a given other process in a repartitioning setting.

Parameters

[in]	start	The first mpi rank to be considered as sender.
[in]	end	The last mpi rank to be considered as sender.
[in]	mpirank	The mpirank to be considered as receiver.
[in]	offset_from	The partition table of the current partition.
[in]	offset_to	The partition table of the next partition.

Returns

The number of processes p, such that start <= p <= end and p does send local trees (and possibly ghosts) to mpirank.

t8_offset_sendsto()

int t8_offset_sendsto	(	int	proca,
		int	procb,
		const t8_gloidx_t *	t8_offset_from,
		const t8_gloidx_t *	t8_offset_to
	)

Query whether in a repartitioning setting, a given process sends local trees (and then possibly ghosts) to a given other process.

Parameters

[in]	proca	Mpi rank of the possible sending process.
[in]	procb	Mpi rank of the possible receiver.
[in]	offset_from	The partition table of the current partition.
[in]	offset_to	The partition table of the next partition.

Returns

nonzero if proca does send local trees to procb when we repartition from offset_from to offset_to. 0 else.

t8_offset_sendstree()

int t8_offset_sendstree	(	int	proc_send,
		int	proc_to,
		t8_gloidx_t	gtree,
		const t8_gloidx_t *	offset_from,
		const t8_gloidx_t *	offset_to
	)

Query whether in a repartitioning setting, a given process sends a given tree to a second process.

Parameters

[in]	proc_send	Mpi rank of the possible sending process.
[in]	proc_recv	Mpi rank of the possible receiver.
[in]	gtree	A global tree id.
[in]	offset_from	The partition table of the current partition.
[in]	offset_to	The partition table of the next partition.

Returns

nonzero if proc_send will send the tree gtree to proc_recv. 0 else. When calling, gtree must not be a local tree of proc_send in offset_from. In this case, 0 is always returned.