The connectivity defines the coarse topology of the forest. More...

#include <sc_io.h>
#include <p4est_base.h>

Include dependency graph for p4est_connectivity.h:

This graph shows which files directly or indirectly include this file:

Data Structures
struct	p4est_connectivity
	This structure holds the 2D inter-tree connectivity information. More...

struct	p4est_corner_transform_t
	Generic interface for transformations between a tree and any of its corner. More...

struct	p4est_corner_info_t
	Information about the neighbors of a corner. More...

struct	p4est_neighbor_transform_t
	Generic interface for transformations between a tree and any of its neighbors. More...

Macros
#define	P4EST_DIM 2
	The spatial dimension.

#define	P4EST_FACES (2 * P4EST_DIM)
	The number of faces of a quadrant.

#define	P4EST_CHILDREN 4
	The number of children of a quadrant, also the number of corners.

#define	P4EST_HALF (P4EST_CHILDREN / 2)
	The number of children/corners touching one face.

#define	P4EST_INSUL 9
	The size of insulation layer.

#define	P4EST_ONLY_P8_LAND(x)
	Only use logical AND term in 3D.

#define	P4EST_ONLY_P8_COMMA(x)
	Only use comma and expression in 3D.

#define	P4EST_DIM_POW(a) ((a) * (a))
	Exponentiate with dimension.

#define	P4EST_FTRANSFORM 9
	Data size of face transformation encoding.

#define	P4EST_STRING "p4est"
	p4est identification string

#define	P4EST_ONDISK_FORMAT 0x2000009
	The revision number of the p4est ondisk file format. More...

Typedefs
typedef struct p4est_connectivity	p4est_connectivity_t
	This structure holds the 2D inter-tree connectivity information. More...

Enumerations
enum	p4est_connect_type_t { P4EST_CONNECT_SELF = 20 , P4EST_CONNECT_FACE = 21 , P4EST_CONNECT_ALMOST = P4EST_CONNECT_FACE , P4EST_CONNECT_CORNER = 22 , P4EST_CONNECT_FULL = P4EST_CONNECT_CORNER }
	Characterize a type of adjacency. More...

enum	p4est_connectivity_encode_t { P4EST_CONN_ENCODE_NONE = SC_IO_ENCODE_NONE , P4EST_CONN_ENCODE_LAST }
	Typedef for serialization method. More...

Functions
int	p4est_connect_type_int (p4est_connect_type_t btype)
	Convert the p4est_connect_type_t into a number. More...

const char *	p4est_connect_type_string (p4est_connect_type_t btype)
	Convert the p4est_connect_type_t into a const string. More...

size_t	p4est_connectivity_memory_used (p4est_connectivity_t *conn)
	Calculate memory usage of a connectivity structure. More...

void	p4est_neighbor_transform_coordinates (const p4est_neighbor_transform_t *nt, const p4est_qcoord_t self_coords[P4EST_DIM], p4est_qcoord_t neigh_coords[P4EST_DIM])
	Transform from self's coordinate system to neighbor's coordinate system. More...

void	p4est_neighbor_transform_coordinates_reverse (const p4est_neighbor_transform_t *nt, const p4est_qcoord_t neigh_coords[P4EST_DIM], p4est_qcoord_t self_coords[P4EST_DIM])
	Transform from neighbor's coordinate system to self's coordinate system. More...

void	p4est_connectivity_get_neighbor_transforms (p4est_connectivity_t conn, p4est_topidx_t tree_id, p4est_connect_type_t boundary_type, int boundary_index, sc_array_t neighbor_transform_array)
	Fill an array with the neighbor transforms based on a specific boundary type. More...

int	p4est_connectivity_face_neighbor_face_corner (int fc, int f, int nf, int o)
	Transform a face corner across one of the adjacent faces into a neighbor tree. More...

int	p4est_connectivity_face_neighbor_corner (int c, int f, int nf, int o)
	Transform a corner across one of the adjacent faces into a neighbor tree. More...

p4est_connectivity_t *	p4est_connectivity_new (p4est_topidx_t num_vertices, p4est_topidx_t num_trees, p4est_topidx_t num_corners, p4est_topidx_t num_ctt)
	Allocate a connectivity structure. More...

p4est_connectivity_t *	p4est_connectivity_new_copy (p4est_topidx_t num_vertices, p4est_topidx_t num_trees, p4est_topidx_t num_corners, const double vertices, const p4est_topidx_t ttv, const p4est_topidx_t ttt, const int8_t ttf, const p4est_topidx_t ttc, const p4est_topidx_t coff, const p4est_topidx_t ctt, const int8_t ctc)
	Allocate a connectivity structure and populate from constants. More...

p4est_connectivity_t *	p4est_connectivity_bcast (p4est_connectivity_t *conn_in, int root, sc_MPI_Comm comm)
	Broadcast a connectivity structure that exists only on one process to all. More...

void	p4est_connectivity_destroy (p4est_connectivity_t *connectivity)
	Destroy a connectivity structure. More...

void	p4est_connectivity_set_attr (p4est_connectivity_t *conn, size_t bytes_per_tree)
	Allocate or free the attribute fields in a connectivity. More...

int	p4est_connectivity_is_valid (p4est_connectivity_t *connectivity)
	Examine a connectivity structure. More...

int	p4est_connectivity_is_equal (p4est_connectivity_t conn1, p4est_connectivity_t conn2)
	Check two connectivity structures for equality. More...

int	p4est_connectivity_sink (p4est_connectivity_t conn, sc_io_sink_t sink)
	Write connectivity to a sink object. More...

sc_array_t *	p4est_connectivity_deflate (p4est_connectivity_t *conn, p4est_connectivity_encode_t code)
	Allocate memory and store the connectivity information there. More...

int	p4est_connectivity_save (const char filename, p4est_connectivity_t connectivity)
	Save a connectivity structure to disk. More...

p4est_connectivity_t *	p4est_connectivity_source (sc_io_source_t *source)
	Read connectivity from a source object. More...

p4est_connectivity_t *	p4est_connectivity_inflate (sc_array_t *buffer)
	Create new connectivity from a memory buffer. More...

p4est_connectivity_t *	p4est_connectivity_load (const char filename, size_t bytes)
	Load a connectivity structure from disk. More...

p4est_connectivity_t *	p4est_connectivity_new_unitsquare (void)
	Create a connectivity structure for the unit square.

p4est_connectivity_t *	p4est_connectivity_new_periodic (void)
	Create a connectivity structure for an all-periodic unit square.

p4est_connectivity_t *	p4est_connectivity_new_rotwrap (void)
	Create a connectivity structure for a periodic unit square. More...

p4est_connectivity_t *	p4est_connectivity_new_circle (void)
	Create a connectivity structure for an donut-like circle. More...

p4est_connectivity_t *	p4est_connectivity_new_drop (void)
	Create a connectivity structure for a five-trees geometry with a hole. More...

p4est_connectivity_t *	p4est_connectivity_new_twotrees (int l_face, int r_face, int orientation)
	Create a connectivity structure for two trees being rotated w.r.t. More...

p4est_connectivity_t *	p4est_connectivity_new_corner (void)
	Create a connectivity structure for a three-tree mesh around a corner.

p4est_connectivity_t *	p4est_connectivity_new_pillow (void)
	Create a connectivity structure for two trees on top of each other.

p4est_connectivity_t *	p4est_connectivity_new_moebius (void)
	Create a connectivity structure for a five-tree moebius band.

p4est_connectivity_t *	p4est_connectivity_new_star (void)
	Create a connectivity structure for a six-tree star.

p4est_connectivity_t *	p4est_connectivity_new_cubed (void)
	Create a connectivity structure for the six sides of a unit cube. More...

p4est_connectivity_t *	p4est_connectivity_new_disk_nonperiodic (void)
	Create a connectivity structure for a five-tree flat spherical disk. More...

p4est_connectivity_t *	p4est_connectivity_new_disk (int periodic_a, int periodic_b)
	Create a connectivity structure for a five-tree flat spherical disk. More...

p4est_connectivity_t *	p4est_connectivity_new_icosahedron (void)
	Create a connectivity for mapping the sphere using an icosahedron. More...

p4est_connectivity_t *	p4est_connectivity_new_shell2d (void)
	Create a connectivity structure that builds a 2d spherical shell. More...

p4est_connectivity_t *	p4est_connectivity_new_disk2d (void)
	Create a connectivity structure that maps a 2d disk. More...

p4est_connectivity_t *	p4est_connectivity_new_bowtie (void)
	Create a connectivity structure that maps a 2d bowtie structure. More...

p4est_connectivity_t *	p4est_connectivity_new_brick (int mi, int ni, int periodic_a, int periodic_b)
	A rectangular m by n array of trees with configurable periodicity. More...

p4est_connectivity_t *	p4est_connectivity_new_byname (const char *name)
	Create connectivity structure from predefined catalogue. More...

p4est_connectivity_t *	p4est_connectivity_refine (p4est_connectivity_t *conn, int num_per_dim)
	Uniformly refine a connectivity. More...

void	p4est_expand_face_transform (int iface, int nface, int ftransform[])
	Fill an array with the axis combination of a face neighbor transform. More...

p4est_topidx_t	p4est_find_face_transform (p4est_connectivity_t *connectivity, p4est_topidx_t itree, int iface, int ftransform[])
	Fill an array with the axis combinations of a tree neighbor transform. More...

void	p4est_find_corner_transform (p4est_connectivity_t connectivity, p4est_topidx_t itree, int icorner, p4est_corner_info_t ci)
	Fills an array with information about corner neighbors. More...

void	p4est_connectivity_complete (p4est_connectivity_t *conn)
	Internally connect a connectivity based on tree_to_vertex information. More...

void	p4est_connectivity_reduce (p4est_connectivity_t *conn)
	Removes corner information of a connectivity such that enough information is left to run p4est_connectivity_complete successfully. More...

void	p4est_connectivity_permute (p4est_connectivity_t conn, sc_array_t perm, int is_current_to_new)
	p4est_connectivity_permute Given a permutation perm of the trees in a connectivity conn, permute the trees of conn in place and update conn to match. More...

void	p4est_connectivity_reorder (sc_MPI_Comm comm, int k, p4est_connectivity_t *conn, p4est_connect_type_t ctype)
	Reorder a connectivity using METIS. More...

sc_array_t *	p4est_connectivity_reorder_newid (sc_MPI_Comm comm, int k, p4est_connectivity_t conn, p4est_connect_type_t ctype, sc_array_t newid)
	Reorder a connectivity using METIS. More...

void	p4est_connectivity_join_faces (p4est_connectivity_t *conn, p4est_topidx_t tree_left, p4est_topidx_t tree_right, int face_left, int face_right, int orientation)
	p4est_connectivity_join_faces This function takes an existing valid connectivity conn and modifies it by joining two tree faces that are currently boundary faces. More...

int	p4est_connectivity_is_equivalent (p4est_connectivity_t conn1, p4est_connectivity_t conn2)
	p4est_connectivity_is_equivalent This function compares two connectivities for equivalence: it returns true if they are the same connectivity, or if they have the same topology. More...

int	p4est_connectivity_read_inp_stream (FILE stream, p4est_topidx_t num_vertices, p4est_topidx_t num_trees, double vertices, p4est_topidx_t *tree_to_vertex)
	Read an ABAQUS input file from a file stream. More...

p4est_connectivity_t *	p4est_connectivity_read_inp (const char *filename)
	Create a p4est connectivity from an ABAQUS input file. More...

Variables
const int	p4est_face_corners [4][2]
	Store the corner numbers 0..4 for each tree face.

const int	p4est_face_dual [4]
	Store the face numbers in the face neighbor's system.

const int	p4est_corner_faces [4][2]
	Store the face numbers 0..3 for each tree corner.

const int	p4est_corner_face_corners [4][4]
	Store the face corner numbers for the faces touching a tree corner.

const int	p4est_child_corner_faces [4][4]
	Store the faces for each child and corner, can be -1.

Detailed Description

The connectivity defines the coarse topology of the forest.

A 2D forest consists of one or more quadtrees, each of which a logical square. Each tree has a local coordinate system, which defines the origin and the direction of its x- and y-axes as well as the numbering of its faces and corners. Each tree may connect to any other tree (including itself) across any of its faces and/or corners, where the neighbor may be arbitrarily rotated and/or flipped. The p4est_connectivity data structure stores these connections.

We impose the following requirement for consistency of p4est_balance :

Note: If a connectivity implies natural connections between trees that are corner neighbors without being face neighbors, these corners shall be encoded explicitly in the connectivity. Please see the documentation of p4est_connectivity_t for the exact encoding convention.

We provide various predefined connectivitys by dedicated constructors, such as

p4est_connectivity_new_unitsquare for the unit square,
p4est_connectivity_new_periodic for the periodic unit square,
p4est_connectivity_new_brick for a rectangular grid of trees,
p4est_connectivity_new_moebius for a nonoriented loop of trees.

Macro Definition Documentation

◆ P4EST_ONDISK_FORMAT

#define P4EST_ONDISK_FORMAT 0x2000009

The revision number of the p4est ondisk file format.

Increase this number whenever the on-disk format for p4est_connectivity, p4est, or any other 2D data structure changes. The format for reading and writing must be the same.

Typedef Documentation

◆ p4est_connectivity_t

typedef struct p4est_connectivity p4est_connectivity_t

This structure holds the 2D inter-tree connectivity information.

Identification of arbitrary faces and corners is possible.

The arrays tree_to_* are stored in z ordering. For corners the order wrt. yx is 00 01 10 11. For faces the order is given by the normal directions -x +x -y +y. Each face has a natural direction by increasing face corner number. Face connections are allocated [0][0]..[0][3]..[num_trees-1][0]..[num_trees-1][3]. If a face is on the physical boundary it must connect to itself.

The values for tree_to_face are 0..7 where ttf % 4 gives the face number and ttf / 4 the face orientation code. The orientation is 0 for faces that are mutually direction-aligned and 1 for faces that are running in opposite directions.

It is valid to specify num_vertices as 0. In this case vertices and tree_to_vertex are set to NULL. Otherwise the vertex coordinates are stored in the array vertices as [0][0]..[0][2]..[num_vertices-1][0]..[num_vertices-1][2]. Vertex coordinates are optional and not used for inferring topology.

The corners are stored when they connect trees that are not already face neighbors at that specific corner. In this case tree_to_corner indexes into ctt_offset. Otherwise the tree_to_corner entry must be -1 and this corner is ignored. If num_corners == 0, tree_to_corner and corner_to_* arrays are set to NULL.

The arrays corner_to_* store a variable number of entries per corner. For corner c these are at position [ctt_offset[c]]..[ctt_offset[c+1]-1]. Their number for corner c is ctt_offset[c+1] - ctt_offset[c]. The entries encode all trees adjacent to corner c. The size of the corner_to_* arrays is num_ctt = ctt_offset[num_corners].

The *_to_attr arrays may have arbitrary contents defined by the user. We do not interpret them.

Note: If a connectivity implies natural connections between trees that are corner neighbors without being face neighbors, these corners shall be encoded explicitly in the connectivity.

Enumeration Type Documentation

◆ p4est_connect_type_t

enum p4est_connect_type_t

Characterize a type of adjacency.

Several functions involve relationships between neighboring trees and/or quadrants, and their behavior depends on how one defines adjacency: 1) entities are adjacent if they share a face, or 2) entities are adjacent if they share a face or corner. p4est_connect_type_t is used to choose the desired behavior. This enum must fit into an int8_t.

Enumerator
P4EST_CONNECT_SELF	No balance whatsoever.
P4EST_CONNECT_FACE	Balance across faces only.
P4EST_CONNECT_ALMOST	= CORNER - 1.
P4EST_CONNECT_CORNER	Balance across faces and corners.
P4EST_CONNECT_FULL	= CORNER.

◆ p4est_connectivity_encode_t

enum p4est_connectivity_encode_t

Typedef for serialization method.

Enumerator
P4EST_CONN_ENCODE_LAST	Invalid entry to close the list.

Function Documentation

◆ p4est_connect_type_int()

int p4est_connect_type_int ( p4est_connect_type_t btype )

Convert the p4est_connect_type_t into a number.

Parameters

[in] btype The balance type to convert.

Returns: Returns 1 or 2.

◆ p4est_connect_type_string()

const char * p4est_connect_type_string ( p4est_connect_type_t btype )

Convert the p4est_connect_type_t into a const string.

Parameters

[in] btype The balance type to convert.

Returns: Returns a pointer to a constant string.

◆ p4est_connectivity_bcast()

p4est_connectivity_t * p4est_connectivity_bcast	(	p4est_connectivity_t *	conn_in,
		int	root,
		sc_MPI_Comm	comm
	)

Broadcast a connectivity structure that exists only on one process to all.

On the other processors, it will be allocated using p4est_connectivity_new.

Parameters

[in]	conn_in	For the root process the connectivity to be broadcast, for the other processes it must be NULL.
[in]	root	The rank of the process that provides the connectivity.
[in]	comm	The MPI communicator.

Returns: For the root process this is a pointer to conn_in. Else, a pointer to a newly allocated connectivity structure with the same values as conn_in on the root process.

◆ p4est_connectivity_complete()

void p4est_connectivity_complete ( p4est_connectivity_t * conn )

Internally connect a connectivity based on tree_to_vertex information.

Periodicity that is not inherent in the list of vertices will be lost.

Parameters

[in,out] conn The connectivity needs to have proper vertices and tree_to_vertex fields. The tree_to_tree and tree_to_face fields must be allocated and satisfy p4est_connectivity_is_valid (conn) but will be overwritten. The corner fields will be freed and allocated anew.

◆ p4est_connectivity_deflate()

sc_array_t * p4est_connectivity_deflate	(	p4est_connectivity_t *	conn,
		p4est_connectivity_encode_t	code
	)

Allocate memory and store the connectivity information there.

Parameters

[in]	conn	The connectivity structure to be exported to memory.
[in]	code	Encoding and compression method for serialization.

Returns: Newly created array that contains the information.

◆ p4est_connectivity_destroy()

void p4est_connectivity_destroy ( p4est_connectivity_t * connectivity )

Destroy a connectivity structure.

Also destroy all attributes.

Examples: points/generate_points2.c, simple/simple2.c, and steps/p4est_step1.c.

◆ p4est_connectivity_face_neighbor_corner()

int p4est_connectivity_face_neighbor_corner	(	int	c,
		int	f,
		int	nf,
		int	o
	)

Transform a corner across one of the adjacent faces into a neighbor tree.

This version expects the neighbor face and orientation separately.

Parameters

[in]	c	A corner number in 0..3.
[in]	f	A face number that touches the corner c.
[in]	nf	A neighbor face that is on the other side of f.
[in]	o	The orientation between tree boundary faces f and nf.

Returns: The number of the corner seen from the neighbor tree.

◆ p4est_connectivity_face_neighbor_face_corner()

int p4est_connectivity_face_neighbor_face_corner	(	int	fc,
		int	f,
		int	nf,
		int	o
	)

Transform a face corner across one of the adjacent faces into a neighbor tree.

This version expects the neighbor face and orientation separately.

Parameters

[in]	fc	A face corner number in 0..1.
[in]	f	A face that the face corner number fc is relative to.
[in]	nf	A neighbor face that is on the other side of f.
[in]	o	The orientation between tree boundary faces f and nf.

Returns: The face corner number relative to the neighbor's face.

◆ p4est_connectivity_get_neighbor_transforms()

void p4est_connectivity_get_neighbor_transforms	(	p4est_connectivity_t *	conn,
		p4est_topidx_t	tree_id,
		p4est_connect_type_t	boundary_type,
		int	boundary_index,
		sc_array_t *	neighbor_transform_array
	)

Fill an array with the neighbor transforms based on a specific boundary type.

This function generalizes all other inter-tree transformation objects

Parameters

[in]	conn	Connectivity structure.
[in]	tree_id	The number of the tree.
[in]	boundary_type	The type of the boundary connection (self, face, corner).
[in]	boundary_index	The index of the boundary.
[in,out]	neighbor_transform_array	Array of the neighbor transforms.

◆ p4est_connectivity_inflate()

p4est_connectivity_t * p4est_connectivity_inflate ( sc_array_t * buffer )

Create new connectivity from a memory buffer.

This function aborts on malloc errors.

Parameters

[in] buffer The connectivity is created from this memory buffer.

Returns: The newly created connectivity, or NULL on format error of the buffered connectivity data.

◆ p4est_connectivity_is_equal()

int p4est_connectivity_is_equal	(	p4est_connectivity_t *	conn1,
		p4est_connectivity_t *	conn2
	)

Check two connectivity structures for equality.

Returns: Returns true if structures are equal, false otherwise.

◆ p4est_connectivity_is_equivalent()

int p4est_connectivity_is_equivalent	(	p4est_connectivity_t *	conn1,
		p4est_connectivity_t *	conn2
	)

p4est_connectivity_is_equivalent This function compares two connectivities for equivalence: it returns true if they are the same connectivity, or if they have the same topology.

The definition of topological sameness is strict: there is no attempt made to determine whether permutation and/or rotation of the trees makes the connectivities equivalent.

Parameters

[in]	conn1	a valid connectivity
[out]	conn2	a valid connectivity

◆ p4est_connectivity_is_valid()

int p4est_connectivity_is_valid ( p4est_connectivity_t * connectivity )

Examine a connectivity structure.

Returns: Returns true if structure is valid, false otherwise.

◆ p4est_connectivity_join_faces()

void p4est_connectivity_join_faces	(	p4est_connectivity_t *	conn,
		p4est_topidx_t	tree_left,
		p4est_topidx_t	tree_right,
		int	face_left,
		int	face_right,
		int	orientation
	)

p4est_connectivity_join_faces This function takes an existing valid connectivity conn and modifies it by joining two tree faces that are currently boundary faces.

Parameters

[in,out]	conn	connectivity that will be altered.
[in]	tree_left	tree that will be on the left side of the joined faces.
[in]	tree_right	tree that will be on the right side of the joined faces.
[in]	face_left	face of tree_left that will be joined.
[in]	face_right	face of tree_right that will be joined.
[in]	orientation	the orientation of face_left and face_right once joined (see the description of p4est_connectivity_t to understand orientation).

◆ p4est_connectivity_load()

p4est_connectivity_t * p4est_connectivity_load	(	const char *	filename,
		size_t *	bytes
	)

Load a connectivity structure from disk.

Parameters

[in]	filename	Name of the file to read.
[in,out]	bytes	Size in bytes of connectivity on disk or NULL.

Returns: Returns valid connectivity, or NULL on file error.

◆ p4est_connectivity_memory_used()

size_t p4est_connectivity_memory_used ( p4est_connectivity_t * conn )

Calculate memory usage of a connectivity structure.

Parameters

[in] conn Connectivity structure.

Returns: Memory used in bytes.

◆ p4est_connectivity_new()

p4est_connectivity_t * p4est_connectivity_new	(	p4est_topidx_t	num_vertices,
		p4est_topidx_t	num_trees,
		p4est_topidx_t	num_corners,
		p4est_topidx_t	num_ctt
	)

Allocate a connectivity structure.

The attribute fields are initialized to NULL.

Parameters

[in]	num_vertices	Number of total vertices (i.e. geometric points).
[in]	num_trees	Number of trees in the forest.
[in]	num_corners	Number of tree-connecting corners.
[in]	num_ctt	Number of total trees in corner_to_tree array.

Returns: A connectivity structure with allocated arrays.

◆ p4est_connectivity_new_bowtie()

p4est_connectivity_t * p4est_connectivity_new_bowtie ( void )

Create a connectivity structure that maps a 2d bowtie structure.

The 2 trees are connected by a corner connection at node A3 (0, 0). the nodes are given as:

   A00   A01
  /   \ /   \
A02   A03   A04
  \   / \   /
   A05   A06

Examples: simple/simple2.c.

◆ p4est_connectivity_new_brick()

p4est_connectivity_t * p4est_connectivity_new_brick	(	int	mi,
		int	ni,
		int	periodic_a,
		int	periodic_b
	)

A rectangular m by n array of trees with configurable periodicity.

The brick is periodic in x and y if periodic_a and periodic_b are true, respectively.

Examples: points/generate_points2.c, and simple/simple2.c.

◆ p4est_connectivity_new_byname()

p4est_connectivity_t * p4est_connectivity_new_byname ( const char * name )

Create connectivity structure from predefined catalogue.

Parameters

[in] name Invokes connectivity_new_* function. brick23 brick (2, 3, 0, 0) corner corner cubed cubed disk disk moebius moebius periodic periodic pillow pillow rotwrap rotwrap star star unit unitsquare

Returns: An initialized connectivity if name is defined, NULL else.

◆ p4est_connectivity_new_circle()

p4est_connectivity_t * p4est_connectivity_new_circle ( void )

Create a connectivity structure for an donut-like circle.

The circle consists of 6 trees connecting each other by their faces. The trees are laid out as a hexagon between [-2, 2] in the y direction and [-sqrt(3), sqrt(3)] in the x direction. The hexagon has flat sides along the y direction and pointy ends in x.

Examples: simple/simple2.c.

◆ p4est_connectivity_new_copy()

p4est_connectivity_t * p4est_connectivity_new_copy	(	p4est_topidx_t	num_vertices,
		p4est_topidx_t	num_trees,
		p4est_topidx_t	num_corners,
		const double *	vertices,
		const p4est_topidx_t *	ttv,
		const p4est_topidx_t *	ttt,
		const int8_t *	ttf,
		const p4est_topidx_t *	ttc,
		const p4est_topidx_t *	coff,
		const p4est_topidx_t *	ctt,
		const int8_t *	ctc
	)

Allocate a connectivity structure and populate from constants.

The attribute fields are initialized to NULL.

Parameters

[in]	num_vertices	Number of total vertices (i.e. geometric points).
[in]	num_trees	Number of trees in the forest.
[in]	num_corners	Number of tree-connecting corners.
[in]	vertices	Coordinates of the vertices of the trees.
[in]	ttv	The tree-to-vertex array.
[in]	ttt	The tree-to-tree array.
[in]	ttf	The tree-to-face array (int8_t).
[in]	ttc	The tree-to-corner array.
[in]	coff	Corner-to-tree offsets (num_corners + 1 values). This must always be non-NULL; in trivial cases it is just a pointer to a p4est_topix value of 0.
[in]	ctt	The corner-to-tree array.
[in]	ctc	The corner-to-corner array.

Returns: The connectivity is checked for validity.

◆ p4est_connectivity_new_cubed()

p4est_connectivity_t * p4est_connectivity_new_cubed ( void )

Create a connectivity structure for the six sides of a unit cube.

The ordering of the trees is as follows:

0 1
  2 3 <-- 3: axis-aligned top side
    4 5

This choice has been made for maximum symmetry (see tree_to_* in .c file).

Examples: simple/simple2.c.

◆ p4est_connectivity_new_disk()

p4est_connectivity_t * p4est_connectivity_new_disk	(	int	periodic_a,
		int	periodic_b
	)

Create a connectivity structure for a five-tree flat spherical disk.

This disk can just as well be used as a square to test non-Cartesian maps. Without any mapping this connectivity covers the square [-3, 3]**2.

Note: The API of this function has changed to accept two arguments. You can query the P4EST_CONN_DISK_PERIODIC to check whether the new version with the argument is in effect.

The ordering of the trees is as follows:

  4
1 2 3
  0

The outside x faces may be identified topologically. The outside y faces may be identified topologically. Both identifications may be specified simultaneously. The general shape and periodicity are the same as those obtained with p4est_connectivity_new_brick (1, 1, periodic_a, periodic_b).

When setting periodic_a and periodic_b to false, the result is the same as that of p4est_connectivity_new_disk_nonperiodic.

Parameters

[in]	periodic_a	Bool to make disk periodic in x direction.
[in]	periodic_b	Bool to make disk periodic in y direction.

Returns: Initialized and usable connectivity.

Examples: simple/simple2.c.

◆ p4est_connectivity_new_disk2d()

p4est_connectivity_t * p4est_connectivity_new_disk2d ( void )

Create a connectivity structure that maps a 2d disk.

This is a 5 trees connectivity meant to be used together with p4est_geometry_new_disk2d to map the disk.

Examples: simple/simple2.c.

◆ p4est_connectivity_new_disk_nonperiodic()

p4est_connectivity_t * p4est_connectivity_new_disk_nonperiodic ( void )

Create a connectivity structure for a five-tree flat spherical disk.

This disk can just as well be used as a square to test non-Cartesian maps. Without any mapping this connectivity covers the square [-3, 3]**2.

Returns: Initialized and usable connectivity.

◆ p4est_connectivity_new_drop()

p4est_connectivity_t * p4est_connectivity_new_drop ( void )

Create a connectivity structure for a five-trees geometry with a hole.

The geometry covers the square [0, 3]**2, where the hole is [1, 2]**2.

Examples: simple/simple2.c.

◆ p4est_connectivity_new_icosahedron()

p4est_connectivity_t * p4est_connectivity_new_icosahedron ( void )

Create a connectivity for mapping the sphere using an icosahedron.

The regular icosadron is a polyhedron with 20 faces, each of which is an equilateral triangle. To build the p4est connectivity, we group faces 2 by 2 to from 10 quadrangles, and thus 10 trees.

This connectivity is meant to be used together with p4est_geometry_new_icosahedron to map the sphere.

The flat connectivity looks like that. Vextex numbering:

   A00   A01   A02   A03   A04
  /   \ /   \ /   \ /   \ /   \
A05---A06---A07---A08---A09---A10
  \   / \   / \   / \   / \   / \
   A11---A12---A13---A14---A15---A16
     \  /  \  /  \  /  \  /  \  /
     A17   A18   A19   A20   A21

Origin in A05.

Tree numbering:

0  2  4  6  8
 1  3  5  7  9

Examples: simple/simple2.c.

◆ p4est_connectivity_new_rotwrap()

p4est_connectivity_t * p4est_connectivity_new_rotwrap ( void )

Create a connectivity structure for a periodic unit square.

The left and right faces are identified, and bottom and top opposite.

Examples: simple/simple2.c.

◆ p4est_connectivity_new_shell2d()

p4est_connectivity_t * p4est_connectivity_new_shell2d ( void )

Create a connectivity structure that builds a 2d spherical shell.

p8est_connectivity_new_shell

Examples: simple/simple2.c.

◆ p4est_connectivity_new_twotrees()

p4est_connectivity_t * p4est_connectivity_new_twotrees	(	int	l_face,
		int	r_face,
		int	orientation
	)

Create a connectivity structure for two trees being rotated w.r.t.

each other in a user-defined way

Parameters

[in]	l_face	index of left face
[in]	r_face	index of right face
[in]	orientation	orientation of trees w.r.t. each other

◆ p4est_connectivity_permute()

void p4est_connectivity_permute	(	p4est_connectivity_t *	conn,
		sc_array_t *	perm,
		int	is_current_to_new
	)

p4est_connectivity_permute Given a permutation perm of the trees in a connectivity conn, permute the trees of conn in place and update conn to match.

Parameters

[in,out]	conn	The connectivity whose trees are permuted.
[in]	perm	A permutation array, whose elements are size_t's.
[in]	is_current_to_new	if true, the jth entry of perm is the new index for the entry whose current index is j, otherwise the jth entry of perm is the current index of the tree whose index will be j after the permutation.

◆ p4est_connectivity_read_inp()

p4est_connectivity_t * p4est_connectivity_read_inp ( const char * filename )

Create a p4est connectivity from an ABAQUS input file.

This utility function reads a basic ABAQUS file supporting element type with the prefix C2D4, CPS4, and S4 in 2D and of type C3D8 reading them as bilinear quadrilateral and trilinear hexahedral trees respectively.

A basic 2D mesh is given below. The *Node section gives the vertex number and x, y, and z components for each vertex. The *Element section gives the 4 vertices in 2D (8 vertices in 3D) of each element in counter clockwise order. So in 2D the nodes are given as:

4                     3
 +-------------------+
 |                   |
 |                   |
 |                   |
 |                   |
 |                   |
 |                   |
 +-------------------+
1                     2

and in 3D they are given as:

8                     7
 +---------------------+
 |\                    |\
 | \                   | \
 |  \                  |  \
 |   \                 |   \
 |   5+---------------------+6
 |    |                |    |
 +----|----------------+    |
 4\   |               3 \   |
   \  |                  \  |
    \ |                   \ |
     \|                    \|
      +---------------------+
      1                     2

*Heading
 box.inp
*Node
1,  -5, -5, 0
2,   5, -5, 0
3,   5,  5, 0
4,  -5,  5, 0
5,   0, -5, 0
6,   5,  0, 0
7,   0,  5, 0
8,  -5,  0, 0
9,   1, -1, 0
10,  0,  0, 0
11, -2,  1, 0
*Element, type=CPS4, ELSET=Surface1
1,  1, 10, 11, 8
2,  3, 10, 9,  6
3,  9, 10, 1,  5
4,  7,  4, 8, 11
5, 11, 10, 3,  7
6,  2,  6, 9,  5

This function reads a mesh from filename and returns an associated p4est connectivity.

Parameters

[in] filename file to read the connectivity from

Returns: an allocated connectivity associated with the mesh in filename or NULL if an error occurred.

◆ p4est_connectivity_read_inp_stream()

int p4est_connectivity_read_inp_stream	(	FILE *	stream,
		p4est_topidx_t *	num_vertices,
		p4est_topidx_t *	num_trees,
		double *	vertices,
		p4est_topidx_t *	tree_to_vertex
	)

Read an ABAQUS input file from a file stream.

This utility function reads a basic ABAQUS file supporting element type with the prefix C2D4, CPS4, and S4 in 2D and of type C3D8 reading them as bilinear quadrilateral and trilinear hexahedral trees respectively.

A basic 2D mesh is given below. The *Node section gives the vertex number and x, y, and z components for each vertex. The *Element section gives the 4 vertices in 2D (8 vertices in 3D) of each element in counter clockwise order. So in 2D the nodes are given as:

4                     3
 +-------------------+
 |                   |
 |                   |
 |                   |
 |                   |
 |                   |
 |                   |
 +-------------------+
1                     2

and in 3D they are given as:

8                     7
 +---------------------+
 |\                    |\
 | \                   | \
 |  \                  |  \
 |   \                 |   \
 |   5+---------------------+6
 |    |                |    |
 +----|----------------+    |
 4\   |               3 \   |
   \  |                  \  |
    \ |                   \ |
     \|                    \|
      +---------------------+
      1                     2

*Heading
 box.inp
*Node
1,  -5, -5, 0
2,   5, -5, 0
3,   5,  5, 0
4,  -5,  5, 0
5,   0, -5, 0
6,   5,  0, 0
7,   0,  5, 0
8,  -5,  0, 0
9,   1, -1, 0
10,  0,  0, 0
11, -2,  1, 0
*Element, type=CPS4, ELSET=Surface1
1,  1, 10, 11, 8
2,  3, 10, 9,  6
3,  9, 10, 1,  5
4,  7,  4, 8, 11
5, 11, 10, 3,  7
6,  2,  6, 9,  5

This code can be called two ways. The first, when vertex==NULL and tree_to_vertex==NULL, is used to count the number of trees and vertices in the connectivity to be generated by the .inp mesh in the stream. The second, when vertices!=NULL and tree_to_vertex!=NULL, fill vertices and tree_to_vertex. In this case num_vertices and num_trees need to be set to the maximum number of entries allocated in vertices and tree_to_vertex.

Parameters

[in,out]	stream	file stream to read the connectivity from
[in,out]	num_vertices	the number of vertices in the connectivity
[in,out]	num_trees	the number of trees in the connectivity
[out]	vertices	the list of `vertices` of the connectivity
[out]	tree_to_vertex	the `tree_to_vertex` map of the connectivity

Returns: 0 if successful and nonzero if not

◆ p4est_connectivity_reduce()

void p4est_connectivity_reduce ( p4est_connectivity_t * conn )

Removes corner information of a connectivity such that enough information is left to run p4est_connectivity_complete successfully.

The reduced connectivity still passes p4est_connectivity_is_valid.

Parameters

[in,out] conn The connectivity to be reduced.

◆ p4est_connectivity_refine()

p4est_connectivity_t * p4est_connectivity_refine	(	p4est_connectivity_t *	conn,
		int	num_per_dim
	)

Uniformly refine a connectivity.

This is useful if you would like to uniformly refine by something other than a power of 2.

Parameters

[in]	conn	A valid connectivity
[in]	num_per_dim	The number of new trees in each direction. Must use no more than P4EST_OLD_QMAXLEVEL bits.

Returns: a refined connectivity.

◆ p4est_connectivity_reorder()

void p4est_connectivity_reorder	(	sc_MPI_Comm	comm,
		int	k,
		p4est_connectivity_t *	conn,
		p4est_connect_type_t	ctype
	)

Reorder a connectivity using METIS.

Note: This function is only available if configured successfully --with-metis.

This function takes a connectivity conn and a parameter k, which will typically be the number of processes, and reorders the trees such that if every processes is assigned (num_trees / k) trees, the communication volume will be minimized. This is intended for use with connectivities that contain a large number of trees. This should be done BEFORE a p4est is created using the connectivity. This is done in place: any data structures that use indices to refer to trees before this procedure will be invalid. Note that this routine calls metis and not parmetis because the connectivity is copied on every process. A communicator is required because I'm not positive that metis is deterministic. ctype determines when an edge exist between two trees in the dual graph used by metis in the reordering.

Parameters

[in]	comm	MPI communicator.
[in]	k	if k > 0, the number of pieces metis will use to guide the reordering; if k = 0, the number of pieces will be determined from the MPI communicator.
[in,out]	conn	connectivity that will be reordered.
[in]	ctype	determines when an edge exists in the dual graph of the connectivity structure.

◆ p4est_connectivity_reorder_newid()

sc_array_t * p4est_connectivity_reorder_newid	(	sc_MPI_Comm	comm,
		int	k,
		p4est_connectivity_t *	conn,
		p4est_connect_type_t	ctype,
		sc_array_t *	newid
	)

Reorder a connectivity using METIS.

Note: This function is only available if configured successfully --with-metis.

This is the same form as p4est_connectivity_reorder but it takes an initialized sc array newid as extra argument. In this way, the users can map old indices to new indices in the case it is necessary (for instance to retrieve high-order nodes previously stored in an array with old indices).

Parameters

[in]	comm	MPI communicator.
[in]	k	if k > 0, the number of pieces metis will use to guide the reordering; if k = 0, the number of pieces will be determined from the MPI communicator.
[in,out]	conn	connectivity that will be reordered.
[in]	ctype	determines when an edge exists in the dual graph of the connectivity structure.
[in,out]	newid	array that maps old tree indices to new ones. newid has to be an sc_array and it has to be initialized (non-NULL) with element size of size_t (using sc_array_new (sizeof (size_t))). Input length arbitrary, output length modified.

◆ p4est_connectivity_save()

int p4est_connectivity_save	(	const char *	filename,
		p4est_connectivity_t *	connectivity
	)

Save a connectivity structure to disk.

Parameters

[in]	filename	Name of the file to write.
[in]	connectivity	Valid connectivity structure.

Returns: Returns 0 on success, nonzero on file error.

◆ p4est_connectivity_set_attr()

void p4est_connectivity_set_attr	(	p4est_connectivity_t *	conn,
		size_t	bytes_per_tree
	)

Allocate or free the attribute fields in a connectivity.

Parameters

[in,out]	conn	The conn->*_to_attr fields must either be NULL or previously be allocated by this function.
[in]	bytes_per_tree	If 0, tree_to_attr is freed (being NULL is ok). If positive, requested space is allocated.

◆ p4est_connectivity_sink()

int p4est_connectivity_sink	(	p4est_connectivity_t *	conn,
		sc_io_sink_t *	sink
	)

Write connectivity to a sink object.

Parameters

[in]	conn	The connectivity to be written.
[in,out]	sink	The connectivity is written into this sink.

Returns: 0 on success, nonzero on error.

◆ p4est_connectivity_source()

p4est_connectivity_t * p4est_connectivity_source ( sc_io_source_t * source )

Read connectivity from a source object.

Parameters

[in,out] source The connectivity is read from this source.

Returns: The newly created connectivity, or NULL on error.

◆ p4est_expand_face_transform()

void p4est_expand_face_transform	(	int	iface,
		int	nface,
		int	ftransform[]
	)

Fill an array with the axis combination of a face neighbor transform.

Parameters

[in]	iface	The number of the originating face.
[in]	nface	Encoded as nface = r * 4 + nf, where nf = 0..3 is the neigbbor's connecting face number and r = 0..1 is the relative orientation to the neighbor's face. This encoding matches p4est_connectivity_t.
[out]	ftransform	This array holds 9 integers. [0,2] The coordinate axis sequence of the origin face, the first referring to the tangential and the second to the normal. A permutation of (0, 1). [3,5] The coordinate axis sequence of the target face. [6,8] Face reversal flag for tangential axis (boolean); face code in [0, 3] for the normal coordinate q: 0: q' = -q 1: q' = q + 1 2: q' = q - 1 3: q' = 2 - q [1,4,7] 0 (unused for compatibility with 3D).

◆ p4est_find_corner_transform()

void p4est_find_corner_transform	(	p4est_connectivity_t *	connectivity,
		p4est_topidx_t	itree,
		int	icorner,
		p4est_corner_info_t *	ci
	)

Fills an array with information about corner neighbors.

Parameters

[in]	connectivity	Connectivity structure.
[in]	itree	The number of the originating tree.
[in]	icorner	The number of the originating corner.
[in,out]	ci	A p4est_corner_info_t structure with initialized array.

◆ p4est_find_face_transform()

p4est_topidx_t p4est_find_face_transform	(	p4est_connectivity_t *	connectivity,
		p4est_topidx_t	itree,
		int	iface,
		int	ftransform[]
	)

Fill an array with the axis combinations of a tree neighbor transform.

Parameters

[in]	connectivity	Connectivity structure.
[in]	itree	The number of the originating tree.
[in]	iface	The number of the originating tree's face.
[out]	ftransform	This array holds 9 integers. [0,2] The coordinate axis sequence of the origin face. [3,5] The coordinate axis sequence of the target face. [6,8] Face reversal flag for axis t; face code for axis n.

See also: p4est_expand_face_transform. [1,4,7] 0 (unused for compatibility with 3D).

Returns: The face neighbor tree if it exists, -1 otherwise.

◆ p4est_neighbor_transform_coordinates()

void p4est_neighbor_transform_coordinates	(	const p4est_neighbor_transform_t *	nt,
		const p4est_qcoord_t	self_coords[P4EST_DIM],
		p4est_qcoord_t	neigh_coords[P4EST_DIM]
	)

Transform from self's coordinate system to neighbor's coordinate system.

Parameters

[in]	nt	A neighbor transform.
[in]	self_coords	Input quadrant coordinates in self coordinates.
[out]	neigh_coords	Coordinates transformed into neighbor coordinates.

◆ p4est_neighbor_transform_coordinates_reverse()

void p4est_neighbor_transform_coordinates_reverse	(	const p4est_neighbor_transform_t *	nt,
		const p4est_qcoord_t	neigh_coords[P4EST_DIM],
		p4est_qcoord_t	self_coords[P4EST_DIM]
	)

Transform from neighbor's coordinate system to self's coordinate system.

Parameters

[in]	nt	A neighbor transform.
[in]	neigh_coords	Input quadrant coordinates in self coordinates.
[out]	self_coords	Coordinates transformed into neighbor coordinates.

Data Structures

Macros

Typedefs

Enumerations

Functions

Variables

Detailed Description

Macro Definition Documentation

◆ P4EST_ONDISK_FORMAT

Typedef Documentation

◆ p4est_connectivity_t

Enumeration Type Documentation

◆ p4est_connect_type_t

◆ p4est_connectivity_encode_t

Function Documentation

◆ p4est_connect_type_int()

◆ p4est_connect_type_string()

◆ p4est_connectivity_bcast()

◆ p4est_connectivity_complete()

◆ p4est_connectivity_deflate()

◆ p4est_connectivity_destroy()

◆ p4est_connectivity_face_neighbor_corner()

◆ p4est_connectivity_face_neighbor_face_corner()

◆ p4est_connectivity_get_neighbor_transforms()

◆ p4est_connectivity_inflate()

◆ p4est_connectivity_is_equal()

◆ p4est_connectivity_is_equivalent()

◆ p4est_connectivity_is_valid()

◆ p4est_connectivity_join_faces()

◆ p4est_connectivity_load()

◆ p4est_connectivity_memory_used()

◆ p4est_connectivity_new()

◆ p4est_connectivity_new_bowtie()

◆ p4est_connectivity_new_brick()

◆ p4est_connectivity_new_byname()

◆ p4est_connectivity_new_circle()

◆ p4est_connectivity_new_copy()

◆ p4est_connectivity_new_cubed()

◆ p4est_connectivity_new_disk()

◆ p4est_connectivity_new_disk2d()

◆ p4est_connectivity_new_disk_nonperiodic()

◆ p4est_connectivity_new_drop()

◆ p4est_connectivity_new_icosahedron()

◆ p4est_connectivity_new_rotwrap()

◆ p4est_connectivity_new_shell2d()

◆ p4est_connectivity_new_twotrees()

◆ p4est_connectivity_permute()

◆ p4est_connectivity_read_inp()

◆ p4est_connectivity_read_inp_stream()

◆ p4est_connectivity_reduce()

◆ p4est_connectivity_refine()

◆ p4est_connectivity_reorder()

◆ p4est_connectivity_reorder_newid()

◆ p4est_connectivity_save()

◆ p4est_connectivity_set_attr()

◆ p4est_connectivity_sink()

◆ p4est_connectivity_source()

◆ p4est_expand_face_transform()

◆ p4est_find_corner_transform()

◆ p4est_find_face_transform()

◆ p4est_neighbor_transform_coordinates()

◆ p4est_neighbor_transform_coordinates_reverse()