p8est_communication.h File Reference

Parallel messaging and support code. More...

#include <p8est.h>

Include dependency graph for p8est_communication.h:

Go to the source code of this file.

Data Structures
struct	p8est_transfer_context
	Context data to allow for split begin/end data transfer. More...

Typedefs
typedef struct p8est_transfer_context	p8est_transfer_context_t
	Context data to allow for split begin/end data transfer.

Functions
int	p8est_bsearch_partition (p4est_gloidx_t target, const p4est_gloidx_t *gfq, int nmemb)
	Given target, find index p such that gfq[p] <= target < gfq[p + 1]. More...
void	p8est_comm_parallel_env_assign (p8est_t *p8est, sc_MPI_Comm mpicomm)
	Assign an MPI communicator to p8est; retrieve parallel environment. More...
void	p8est_comm_parallel_env_duplicate (p8est_t *p8est)
	Duplicate MPI communicator and replace the current one by the duplicate. More...
void	p8est_comm_parallel_env_release (p8est_t *p8est)
	Release MPI communicator if it is owned by p8est.
void	p8est_comm_parallel_env_replace (p8est_t *p8est, sc_MPI_Comm mpicomm)
	Replace the current MPI communicator by the one provided as input. More...
void	p8est_comm_parallel_env_get_info (p8est_t *p8est)
	Retrieve parallel environment information.
int	p8est_comm_parallel_env_is_null (p8est_t *p8est)
	Check if the MPI communicator is valid. More...
int	p8est_comm_parallel_env_reduce (p8est_t **p8est_supercomm)
	Reduce MPI communicator to non-empty ranks (i.e., nonzero quadrant counts). More...
int	p8est_comm_parallel_env_reduce_ext (p8est_t **p8est_supercomm, sc_MPI_Group group_add, int add_to_beginning, int **ranks_subcomm)
	Reduce MPI communicator to non-empty ranks and add a group of ranks that will remain in the reduced communicator regardless whether they are empty or not. More...
void	p8est_comm_count_quadrants (p8est_t *p8est)
	Calculate the number and partition of quadrants. More...
void	p8est_comm_global_partition (p8est_t *p8est, p8est_quadrant_t *first_quad)
	Distribute the global partition boundaries. More...
void	p8est_comm_global_first_quadrant (p4est_gloidx_t global_num_quadrants, int mpisize, p4est_gloidx_t *gfq)
	Calculate the global fist quadrant array for a uniform partition. More...
void	p8est_comm_count_pertree (p8est_t *p8est, p4est_gloidx_t *pertree)
	Compute and distribute the cumulative number of quadrants per tree. More...
int	p8est_comm_is_empty (p8est_t *p8est, int p)
	Query whether a processor has no quadrants. More...
int	p8est_comm_is_empty_gfq (const p4est_gloidx_t *gfq, int num_procs, int p)
	Query whether a processor has no quadrants. More...
int	p8est_comm_is_empty_gfp (const p8est_quadrant_t *gfp, int num_procs, int p)
	Query whether a processor has no quadrants. More...
int	p8est_comm_is_contained (p8est_t *p8est, p4est_locidx_t which_tree, const p8est_quadrant_t *q, int rank)
	Test whether a quadrant is fully contained in a rank's owned region. More...
int	p8est_comm_is_owner (p8est_t *p8est, p4est_locidx_t which_tree, const p8est_quadrant_t *q, int rank)
	Test ownership of a quadrant via p8est->global_first_position. More...
int	p8est_comm_is_owner_gfp (const p8est_quadrant_t *gfp, int num_procs, p4est_topidx_t num_trees, p4est_locidx_t which_tree, const p8est_quadrant_t *q, int rank)
	Test ownership of a quadrant via a global_first_position array. More...
int	p8est_comm_find_owner (p8est_t *p8est, p4est_locidx_t which_tree, const p8est_quadrant_t *q, int guess)
	Searches the owner of a quadrant via p8est->global_first_position. More...
void	p8est_comm_tree_info (p8est_t *p8est, p4est_locidx_t which_tree, int full_tree[], int tree_contact[], const p8est_quadrant_t **firstq, const p8est_quadrant_t **nextq)
	Computes information about a tree being fully owned. More...
int	p8est_comm_neighborhood_owned (p8est_t *p8est, p4est_locidx_t which_tree, int full_tree[], int tree_contact[], p8est_quadrant_t *q)
	Test if the 3x3 neighborhood of a quadrant is owned by this processor. More...
int	p8est_comm_sync_flag (p8est_t *p8est, int flag, sc_MPI_Op operation)
	Evaluates true/false of a flag among processors. More...
unsigned	p8est_comm_checksum (p8est_t *p8est, unsigned local_crc, size_t local_bytes)
	Compute a parallel partition-independent checksum out of local checksums. More...
void	p8est_transfer_fixed (const p4est_gloidx_t *dest_gfq, const p4est_gloidx_t *src_gfq, sc_MPI_Comm mpicomm, int tag, void *dest_data, const void *src_data, size_t data_size)
	Transfer data associated with one forest partition to another. More...
p8est_transfer_context_t *	p8est_transfer_fixed_begin (const p4est_gloidx_t *dest_gfq, const p4est_gloidx_t *src_gfq, sc_MPI_Comm mpicomm, int tag, void *dest_data, const void *src_data, size_t data_size)
	Initiate a fixed-size data transfer between partitions. More...
void	p8est_transfer_fixed_end (p8est_transfer_context_t *tc)
	Complete a fixed-size data transfer between partitions. More...
void	p8est_transfer_custom (const p4est_gloidx_t *dest_gfq, const p4est_gloidx_t *src_gfq, sc_MPI_Comm mpicomm, int tag, void *dest_data, const int *dest_sizes, const void *src_data, const int *src_sizes)
	Transfer variable-size quadrant data between partitions. More...
p8est_transfer_context_t *	p8est_transfer_custom_begin (const p4est_gloidx_t *dest_gfq, const p4est_gloidx_t *src_gfq, sc_MPI_Comm mpicomm, int tag, void *dest_data, const int *dest_sizes, const void *src_data, const int *src_sizes)
	Initiate a variable-size data transfer between partitions. More...
void	p8est_transfer_custom_end (p8est_transfer_context_t *tc)
	Complete a variable-size data transfer between partitions. More...
void	p8est_transfer_items (const p4est_gloidx_t *dest_gfq, const p4est_gloidx_t *src_gfq, sc_MPI_Comm mpicomm, int tag, void *dest_data, const int *dest_counts, const void *src_data, const int *src_counts, size_t item_size)
	Transfer variable-count item data between partitions. More...
p8est_transfer_context_t *	p8est_transfer_items_begin (const p4est_gloidx_t *dest_gfq, const p4est_gloidx_t *src_gfq, sc_MPI_Comm mpicomm, int tag, void *dest_data, const int *dest_counts, const void *src_data, const int *src_counts, size_t item_size)
	Initiate a variable-count item transfer between partitions. More...
void	p8est_transfer_items_end (p8est_transfer_context_t *tc)
	Complete a variable-count item transfer between partitions. More...
void	p8est_transfer_end (p8est_transfer_context_t *tc)
	Complete any of the transfer_begin functions. More...

Detailed Description

Parallel messaging and support code.

Function Documentation

p8est_bsearch_partition()

int p8est_bsearch_partition	(	p4est_gloidx_t	target,
		const p4est_gloidx_t *	gfq,
		int	nmemb
	)

Given target, find index p such that gfq[p] <= target < gfq[p + 1].

Parameters

[in]	target	The value that is searched in gfq. target has to satisfy gfq[0] <= target < gfq[nmemb].
[in]	gfq	The sorted array (ascending) in that the function will search.
[in]	nmemb	Number of entries in array MINUS ONE.

Returns

Index p such that gfq[p] <= target < gfq[p + 1].

Note

This function differs from p8est_find_partition since p8est_find_partition searches for two targets using binary search in an optimized way but p8est_bsearch_partition only performs a single binary search.

p8est_comm_checksum()

unsigned p8est_comm_checksum	(	p8est_t *	p8est,
		unsigned	local_crc,
		size_t	local_bytes
	)

Compute a parallel partition-independent checksum out of local checksums.

This checksum depends on the global refinement topology. It does not depend on how the mesh is partitioned. The result is available on all processors.

Parameters

[in]	p8est	The MPI information of this p8est will be used.
[in]	local_crc	Locally computed adler32 checksum.
[in]	local_bytes	Number of bytes used for local checksum.

Returns

Parallel checksum on all processors.

p8est_comm_count_pertree()

void p8est_comm_count_pertree	(	p8est_t *	p8est,
		p4est_gloidx_t *	pertree
	)

Compute and distribute the cumulative number of quadrants per tree.

Parameters

[in]	p8est	This p8est needs to have correct values for global_first_quadrant and global_first_position.
[in,out]	pertree	On input, memory for num_trees + 1 numbers. On output, the cumulative quadrant counts.

p8est_comm_count_quadrants()

void p8est_comm_count_quadrants

(

p8est_t *

p8est

)

Calculate the number and partition of quadrants.

Parameters

[in,out]

p8est

Adds all p8est->local_num_quadrant counters and puts cumulative sums in p8est->global_first_quadrant.

p8est_comm_find_owner()

int p8est_comm_find_owner	(	p8est_t *	p8est,
		p4est_locidx_t	which_tree,
		const p8est_quadrant_t *	q,
		int	guess
	)

Searches the owner of a quadrant via p8est->global_first_position.

Assumes a tree with no overlaps.

Parameters

[in]

guess

Initial guess for the search.

Returns

Returns the processor id of the owner.

p8est_comm_global_first_quadrant()

void p8est_comm_global_first_quadrant	(	p4est_gloidx_t	global_num_quadrants,
		int	mpisize,
		p4est_gloidx_t *	gfq
	)

Calculate the global fist quadrant array for a uniform partition.

Parameters

[in]	global_num_quadrants	The global number of quadrants.
[in]	mpisize	The number of MPI ranks.
[in,out]	gfq	At least allocated mpisize + 1 p4est_gloidx_t. This array is filled with the global first quadrant array assuming a uniform partition.

p8est_comm_global_partition()

void p8est_comm_global_partition	(	p8est_t *	p8est,
		p8est_quadrant_t *	first_quad
	)

Distribute the global partition boundaries.

Parameters

[in,out]	p8est	Fills p8est->global_first_position. p8est->first_local_tree must be set correctly. If this processor is not empty and first_quad is NULL, the first quadrant of the first local tree must be set correctly.
[in]	first_quad	If not NULL will be used as first quadrant.

p8est_comm_is_contained()

int p8est_comm_is_contained	(	p8est_t *	p8est,
		p4est_locidx_t	which_tree,
		const p8est_quadrant_t *	q,
		int	rank
	)

Test whether a quadrant is fully contained in a rank's owned region.

This function may return false when p8est_comm_is_owner returns true.

Parameters

[in]

rank

Rank whose ownership is tested. Assumes a forest with no overlaps.

Returns

true if rank is the owner of the whole area of the quadrant.

p8est_comm_is_empty()

int p8est_comm_is_empty	(	p8est_t *	p8est,
		int	p
	)

Query whether a processor has no quadrants.

Parameters

[in]	p8est	This forests' global_first_position array must be valid.
[in]	p	Valid processor id.

Returns

True if and only if processor is empty.

p8est_comm_is_empty_gfp()

int p8est_comm_is_empty_gfp	(	const p8est_quadrant_t *	gfp,
		int	num_procs,
		int	p
	)

Query whether a processor has no quadrants.

Parameters

[in]	gfp	An array encoding the partition shape. Non-decreasing; length num_procs + 1.
[in]	num_procs	Number of processes in the partition.
[in]	p	Valid 0 <= p < num_procs.

Returns

True if and only if processor p is empty.

p8est_comm_is_empty_gfq()

int p8est_comm_is_empty_gfq	(	const p4est_gloidx_t *	gfq,
		int	num_procs,
		int	p
	)

Query whether a processor has no quadrants.

Parameters

[in]	gfq	An array encoding the partition offsets in the global quadrant array; length num_procs + 1.
[in]	num_procs	Number of processes in the partition.
[in]	p	Valid 0 <= p < num_procs.

Returns

True if and only if processor p is empty.

p8est_comm_is_owner()

int p8est_comm_is_owner	(	p8est_t *	p8est,
		p4est_locidx_t	which_tree,
		const p8est_quadrant_t *	q,
		int	rank
	)

Test ownership of a quadrant via p8est->global_first_position.

The quadrant is considered owned if its first descendant is owned. Thus, a positive result occurs even if its last descendant overlaps a higher process.

Parameters

[in]	p8est	Valid forest.
[in]	which_tree	Valid tree number wrt. the forest.
[in]	q	Valid quadrant wrt. the forest.
[in]	rank	Rank whose ownership is tested.

Returns

True if rank is the owner of the first descendant.

p8est_comm_is_owner_gfp()

int p8est_comm_is_owner_gfp	(	const p8est_quadrant_t *	gfp,
		int	num_procs,
		p4est_topidx_t	num_trees,
		p4est_locidx_t	which_tree,
		const p8est_quadrant_t *	q,
		int	rank
	)

Test ownership of a quadrant via a global_first_position array.

This array encodes part of the partition of a valid forest object. The quadrant is considered owned if its first descendant is owned. Thus, a positive result occurs even if its last descendant overlaps a higher process.

Parameters

[in]	gfp	Position array of length num_procs + 1.
[in]	num_procs	Number of processes in this context.
[in]	num_trees	Number of trees in this context.
[in]	which_tree	Valid tree number wrt. the forest.
[in]	q	Valid quadrant wrt. the forest.
[in]	rank	Rank whose ownership is tested.

Returns

True if rank is the owner of the first descendant.

p8est_comm_neighborhood_owned()

int p8est_comm_neighborhood_owned	(	p8est_t *	p8est,
		p4est_locidx_t	which_tree,
		int	full_tree[],
		int	tree_contact[],
		p8est_quadrant_t *	q
	)

Test if the 3x3 neighborhood of a quadrant is owned by this processor.

Parameters

[in]	p8est	The p8est to work on.
[in]	which_tree	The tree index to work on.
[in]	full_tree	Flags as computed by p8est_comm_tree_info.
[in]	tree_contact	Flags as computed by p8est_comm_tree_info.
[in]	q	The quadrant to be checked.

Returns

Returns true iff this quadrant's 3x3 neighborhood is owned.

p8est_comm_parallel_env_assign()

void p8est_comm_parallel_env_assign	(	p8est_t *	p8est,
		sc_MPI_Comm	mpicomm
	)

Assign an MPI communicator to p8est; retrieve parallel environment.

Parameters

[in]

mpicomm

A valid MPI communicator.

Note

The provided MPI communicator is not owned by p8est.

p8est_comm_parallel_env_duplicate()

void p8est_comm_parallel_env_duplicate

(

p8est_t *

p8est

)

Duplicate MPI communicator and replace the current one by the duplicate.

Note

The duplicated MPI communicator is owned by p8est.

p8est_comm_parallel_env_is_null()

int p8est_comm_parallel_env_is_null

(

p8est_t *

p8est

)

Check if the MPI communicator is valid.

Returns

True if communicator is not NULL communicator, false otherwise.

p8est_comm_parallel_env_reduce()

int p8est_comm_parallel_env_reduce

(

p8est_t **

p8est_supercomm

)

Reduce MPI communicator to non-empty ranks (i.e., nonzero quadrant counts).

Parameters

[in,out]

p8est_supercomm

Object which communicator is reduced. Points to NULL if this p8est does not exists.

Returns

True if p8est exists on this MPI rank after reduction.

p8est_comm_parallel_env_reduce_ext()

int p8est_comm_parallel_env_reduce_ext	(	p8est_t **	p8est_supercomm,
		sc_MPI_Group	group_add,
		int	add_to_beginning,
		int **	ranks_subcomm
	)

Reduce MPI communicator to non-empty ranks and add a group of ranks that will remain in the reduced communicator regardless whether they are empty or not.

Parameters

[in,out]	p8est_supercomm	Object which communicator is reduced. Points to NULL if this p8est does not exists.
[in]	group_add	Group of ranks that will remain in communicator.
[in]	add_to_beginning	If true, ranks will be added to the beginning of the reduced communicator, otherwise to the end.
[out]	ranks_subcomm	If not null, array of size 'subcommsize' with subcommrank->supercommrank map.

Returns

True if p8est exists on this MPI rank after reduction.

p8est_comm_parallel_env_replace()

void p8est_comm_parallel_env_replace	(	p8est_t *	p8est,
		sc_MPI_Comm	mpicomm
	)

Replace the current MPI communicator by the one provided as input.

Parameters

[in]

mpicomm

A valid MPI communicator.

Note

The provided MPI communicator is not owned by p8est.

p8est_comm_sync_flag()

int p8est_comm_sync_flag	(	p8est_t *	p8est,
		int	flag,
		sc_MPI_Op	operation
	)

Evaluates true/false of a flag among processors.

Parameters

[in]	p8est	The MPI communicator of this p8est will be used.
[in]	flag	The variable to communicate.
[in]	operation	Either sc_MPI_BAND or sc_MPI_BOR (not used bitwise).

Returns

Returns the logical AND resp. OR of all processors' flags.

p8est_comm_tree_info()

void p8est_comm_tree_info	(	p8est_t *	p8est,
		p4est_locidx_t	which_tree,
		int	full_tree[],
		int	tree_contact[],
		const p8est_quadrant_t **	firstq,
		const p8est_quadrant_t **	nextq
	)

Computes information about a tree being fully owned.

This is determined separately for the beginning and end of the tree.

Parameters

[in]	p8est	The p8est to work on.
[in]	which_tree	The tree in question must be partially owned.
[out]	full_tree	Full ownership of beginning and end of tree.
[out]	tree_contact	True if there are neighbors across the face.
[out]	firstq	Smallest possible first quadrant on this core.
[out]	nextq	Smallest possible first quadrant on next core. Any of tree_contact, firstq and nextq may be NULL.

p8est_transfer_custom()

void p8est_transfer_custom	(	const p4est_gloidx_t *	dest_gfq,
		const p4est_gloidx_t *	src_gfq,
		sc_MPI_Comm	mpicomm,
		int	tag,
		void *	dest_data,
		const int *	dest_sizes,
		const void *	src_data,
		const int *	src_sizes
	)

Transfer variable-size quadrant data between partitions.

(See p8est_transfer_fixed that is optimized for fixed-size data.) The destination process may not know the data size for the elements it receives. In this case the sizes need to be obtained separately in advance, for example by calling p8est_transfer_fixed with src_sizes as payload data, or alternatively its split begin/end versions.

Parameters

[in]	dest_gfq	The target partition encoded as a p8est->global_first_quadrant array. Has mpisize 1 members, must be non-decreasing and satisfy gfq[0] == 0, gfq[mpisize] == global_num_quadrants.
[in]	src_gfq	The original partition, analogous to dest_gfq.
[in]	mpicomm	The communicator to use. Its mpisize must match dest_gfq and src_gfq.
[in]	tag	This tag is used in all messages. The user must guarantee that mpicomm and tag do not conflict with other messages in transit.
[out]	dest_data	User-allocated memory of sum_{i in dest->local_num_quadrants} dest_sizes [i] many bytes is received into. See below about how to choose its size.
[in]	dest_sizes	User-allocated memory of one integer for each quadrant, storing the data size to receive for it. We understand that the sizes are often not known a priori, in which case they can be obtained by a prior call to p8est_transfer_fixed. Optionally the split begin/end versions can be used for added flexibility and overlapping of messages. We use the type int to minimize the message size, and to conform to MPI that has no type for size_t.
[in]	src_data	User-allocated memory of sum_{i in src->local_num_quadrants} src_sizes [i] many bytes is sent from.
[in]	src_sizes	User-allocated memory of one integer for each quadrant, storing the data size to send for it. We use the type int to minimize the message size, and to conform to MPI that has no type for size_t.

p8est_transfer_custom_begin()

p8est_transfer_context_t* p8est_transfer_custom_begin	(	const p4est_gloidx_t *	dest_gfq,
		const p4est_gloidx_t *	src_gfq,
		sc_MPI_Comm	mpicomm,
		int	tag,
		void *	dest_data,
		const int *	dest_sizes,
		const void *	src_data,
		const int *	src_sizes
	)

Initiate a variable-size data transfer between partitions.

See p8est_transfer_custom for a full description. Must be matched with p8est_transfer_custom_end for completion. All parameters must stay alive until the completion has been called.

Parameters

[in]	dest_gfq	The target partition encoded as a p8est->global_first_quadrant array. Has mpisize 1 members, must be non-decreasing and satisfy gfq[0] == 0, gfq[mpisize] == global_num_quadrants.
[in]	src_gfq	The original partition, analogous to dest_gfq.
[in]	mpicomm	The communicator to use. Its mpisize must match dest_gfq and src_gfq.
[in]	tag	This tag is used in all messages. The user must guarantee that mpicomm and tag do not conflict with other messages in transit.
[out]	dest_data	User-allocated memory of sum_{i in dest->local_num_quadrants} dest_sizes [i] many bytes is received into. It must not be accessed before completion with p8est_transfer_custom_end. See below about how to choose its size.
[in]	dest_sizes	User-allocated memory of one integer for each quadrant, storing the data size to receive for it. We understand that the sizes are often not known a priori, in which case they can be obtained by a prior call to p8est_transfer_fixed. Optionally the split begin/end versions can be used for added flexibility and overlapping of messages. We use the type int to minimize the message size, and to conform to MPI that has no type for size_t.
[in]	src_data	User-allocated memory of sum_{i in src->local_num_quadrants} src_sizes [i] many bytes is sent from. It must not be accessed before completion with p8est_transfer_custom_end.
[in]	src_sizes	User-allocated memory of one integer for each quadrant, storing the data size to send for it. We use the type int to minimize the message size, and to conform to MPI that has no type for size_t.

Returns

The context object must be passed to the matching call to p8est_transfer_custom_end.

p8est_transfer_custom_end()

void p8est_transfer_custom_end

(

p8est_transfer_context_t *

tc

)

Complete a variable-size data transfer between partitions.

Waits for remaining messages to complete and frees the transfer context.

Parameters

[in]

tc

Context data from p8est_transfer_custom_begin. Is deallocated before this function returns.

p8est_transfer_end()

void p8est_transfer_end

(

p8est_transfer_context_t *

tc

)

Complete any of the transfer_begin functions.

The specialized transfer_end functions are recommended over this one for slightly stricter error checking: p8est_transfer_fixed_end, p8est_transfer_custom_end, and p8est_transfer_items_end.

Parameters

[in,out]

tc

A valid context from one of the begin functions. This function waits for remaining communications to complete and frees the transfer context.

p8est_transfer_fixed()

void p8est_transfer_fixed	(	const p4est_gloidx_t *	dest_gfq,
		const p4est_gloidx_t *	src_gfq,
		sc_MPI_Comm	mpicomm,
		int	tag,
		void *	dest_data,
		const void *	src_data,
		size_t	data_size
	)

Transfer data associated with one forest partition to another.

In p8est_partition, each quadrant's user data is transferred. If the application maintains per-quadrant data outside of the p8est object, this function can be used to transfer it, matching the call to partition. This variant of the function assumes that the quadrant data size is fixed. It sends point-to-point messages only and is blocking collective. There is a split collective version; see the functions p8est_transfer_fixed_begin and p8est_transfer_fixed_end.

Parameters

[in]	dest_gfq	The target partition encoded as a p8est->global_first_quadrant array. Has mpisize 1 members, must be non-decreasing and satisfy gfq[0] == 0, gfq[mpisize] == global_num_quadrants.
[in]	src_gfq	The original partition, analogous to dest_gfq.
[in]	mpicomm	The communicator to use. Its mpisize must match dest_gfq and src_gfq.
[in]	tag	This tag is used in all messages. The user must guarantee that mpicomm and tag do not conflict with other messages in transit.
[out]	dest_data	User-allocated memory of size data_size * dest->local_num_quadrants is received into.
[in]	src_data	User-allocated memory of size data_size * src->local_num_quadrants bytes is sent from.
[in]	data_size	Fixed data size per quadrant.

p8est_transfer_fixed_begin()

p8est_transfer_context_t* p8est_transfer_fixed_begin	(	const p4est_gloidx_t *	dest_gfq,
		const p4est_gloidx_t *	src_gfq,
		sc_MPI_Comm	mpicomm,
		int	tag,
		void *	dest_data,
		const void *	src_data,
		size_t	data_size
	)

Initiate a fixed-size data transfer between partitions.

See p8est_transfer_fixed for a full description. Must be matched with p8est_transfer_fixed_end for completion. All parameters must stay alive until the completion has been called.

Parameters

[in]	dest_gfq	The target partition encoded as a p8est->global_first_quadrant array. Has mpisize 1 members, must be non-decreasing and satisfy gfq[0] == 0, gfq[mpisize] == global_num_quadrants.
[in]	src_gfq	The original partition, analogous to dest_gfq.
[in]	mpicomm	The communicator to use. Its mpisize must match dest_gfq and src_gfq.
[in]	tag	This tag is used in all messages. The user must guarantee that mpicomm and tag do not conflict with other messages in transit.
[out]	dest_data	User-allocated memory of size data_size * dest->local_num_quadrants bytes is received into. It must not be accessed before completion with p8est_transfer_fixed_end.
[in]	src_data	User-allocated memory of size data_size * src->local_num_quadrants bytes is sent from. It must not be accessed before completion with p8est_transfer_fixed_end.
[in]	data_size	Fixed data size per quadrant.

Returns

The context object must be passed to the matching call to p8est_transfer_fixed_end.

p8est_transfer_fixed_end()

void p8est_transfer_fixed_end

(

p8est_transfer_context_t *

tc

)

Complete a fixed-size data transfer between partitions.

Waits for remaining messages to complete and frees the transfer context.

Parameters

[in]

tc

Context data from p8est_transfer_fixed_begin. Is deallocated before this function returns.

p8est_transfer_items()

void p8est_transfer_items	(	const p4est_gloidx_t *	dest_gfq,
		const p4est_gloidx_t *	src_gfq,
		sc_MPI_Comm	mpicomm,
		int	tag,
		void *	dest_data,
		const int *	dest_counts,
		const void *	src_data,
		const int *	src_counts,
		size_t	item_size
	)

Transfer variable-count item data between partitions.

Each quadrant may have a different number of items (including 0). (See p8est_transfer_fixed that is optimized for fixed-count data, and p8est_transfer_custom for data that is not itemized at all.) The destination process may not know the item count for the elements it receives. In this case the counts need to be obtained separately in advance, for example by calling p8est_transfer_fixed with src_counts as payload data, or alternatively its split begin/end versions.

Parameters

[in]	dest_gfq	The target partition encoded as a p8est->global_first_quadrant array. Has mpisize 1 members, must be non-decreasing and satisfy gfq[0] == 0, gfq[mpisize] == global_num_quadrants.
[in]	src_gfq	The original partition, analogous to dest_gfq.
[in]	mpicomm	The communicator to use. Its mpisize must match dest_gfq and src_gfq.
[in]	tag	This tag is used in all messages. The user must guarantee that mpicomm and tag do not conflict with other messages in transit.
[out]	dest_data	User-allocated memory of sum_{i in dest->local_num_quadrants} item_size dest_counts[i] many bytes is received into. See below about how to choose its size. If dest has data to transfer, must be non-NULL.
[in]	dest_counts	User-allocated memory of one integer for each quadrant, storing the item count to receive for it. We understand that the counts are often not known a priori, in which case they can be obtained by a prior call to p8est_transfer_fixed. Optionally the split begin/end versions can be used for added flexibility and overlapping of messages. We use the type int to minimize the message size, and to conform to MPI that has no type for size_t. If dest has quadrants, must be non-NULL.
[in]	src_data	User-allocated memory of sum_{i in src->local_num_quadrants} item_size src_counts[i] many bytes is sent from. If src has data to transfer, must be non-NULL.
[in]	src_counts	User-allocated memory of one integer for each quadrant, storing the item count to send for it. We use the type int to minimize the message size, and to conform to MPI that has no type for size_t. If src has quadrants, must be non-NULL.
[in]	item_size	Data size for each item in bytes.

p8est_transfer_items_begin()

p8est_transfer_context_t* p8est_transfer_items_begin	(	const p4est_gloidx_t *	dest_gfq,
		const p4est_gloidx_t *	src_gfq,
		sc_MPI_Comm	mpicomm,
		int	tag,
		void *	dest_data,
		const int *	dest_counts,
		const void *	src_data,
		const int *	src_counts,
		size_t	item_size
	)

Initiate a variable-count item transfer between partitions.

See p8est_transfer_items for a full description. This functions calls asynchronous MPI send/receive and returns. Must be matched with p8est_transfer_items_end for completion, which calls blocking MPI wait until all messages have been processed. All parameters must stay alive until the completion has been called.

p8est_transfer_items_end()

void p8est_transfer_items_end

(

p8est_transfer_context_t *

tc

)

Complete a variable-count item transfer between partitions.

Waits for remaining messages to complete and frees the transfer context.

Parameters

[in]

tc

Context data from p8est_transfer_items_begin. Is deallocated before this function returns.