Data structures

In mmg, several data structures are defined in order to represent and manipulate different entities such as tetrahedra, triangles, or meshes.

Mesh

The main data structure that is used throughout mmg is the mesh structure MMG5_Mesh. This structure contains the following fields:

struct MMG5_Mesh

size_t memMax

Maximum memory available

size_t memCur

Current memory used

double gap

Gap for table reallocation

int ver

Version of the mesh file

int dim

Dimension of the mesh

int type

Type of the mesh

MMG5_int npi

Number of ??

MMG5_int nti

Number of ??

MMG5_int nai

Number of ??

MMG5_int nei

Number of ??

MMG5_int np

Number of ??

MMG5_int na

Number of ??

MMG5_int nt

Number of ??

MMG5_int ne

Number of ??

MMG5_int npmax

Number of ??

MMG5_int namax

Number of ??

MMG5_int ntmax

Number of ??

MMG5_int nemax

Number of ??

MMG5_int xpmax

Number of ??

MMG5_int xtmax

Number of ??

MMG5_int nquad

number of quadrangles

MMG5_int nprism

number of prisms

int nsols

number of solutions (metric excluded) in the solution file (lower than a NSOLS_MAX)

MMG5_int nc1

number of ??

MMG5_int base

Used with a flag to know if an entity has been treated

MMG5_int mark

Flag for delaunay (to know if an entity has been treated)

MMG5_int xp

Number of surface points

MMG5_int xt

Number of triangles/tetrahedra

MMG5_int xpr

Number of prisms

MMG5_int npnil

Index of first unused point

MMG5_int nenil

Index of first unused element

MMG5_int nanil

Index of first unused edge (2D only)

MMG5_int *adja

!< Table of tetrahedron adjacency: if

\f\(adja[4*(i-1)+1+j]=4*k+l\f\) then the \f\(i^{th}\f\) and \f\(k^th\f\) tetrahedra are adjacent and share their faces \a j and \a l (resp.)

MMG5_int *adjt

Table of triangles adjacency: if

\f\(adjt[3*(i-1)+1+j]=3*k+l\f\) then the \f\(i^{th}\f\) and \f\(k^th\f\) triangles are adjacent and share their edges \a j and \a l (resp.)

MMG5_int *adjapr

Table of prisms adjacency: if

\f\(adjapr[5*(i-1)+1+j]=5*k+l\f\) then the \f\(i^{th}\f\) and \f\(k^th\f\) prism are adjacent and share their faces \a j and \a l (resp.)

MMG5_int *adjq

Table of quadrangles adjacency: if

\f\(adjq[4*(i-1)+1+j]=4*k+l\f\) then the \f\(i^{th}\f\) and \f\(k^th\f\) quadrilaterals are adjacent and share their edges \a j and \a l (resp.)

int *ipar

Store indices of the local parameters

MMG5_pPoint Point

Pointer toward the MMG5_Point structure

MMG5_pxPoint xPoint

Pointer toward the MMG5_Point structure

MMG5_pTetra tetra

Pointer toward the MMG5_Point structure

MMG5_pxTetra xtetra

Pointer toward the MMG5_Point structure

MMG5_pPrism prism

Pointer toward the MMG5_Point structure

MMG5_pxPrism xprism

Pointer toward the MMG5_Point structure

MMG5_pTria tria

Pointer toward the MMG5_Point structure

MMG5_pQuad quadra

Pointer toward the MMG5_Point structure

MMG5_pEdge edge

Pointer toward the MMG5_Point structure

MMG5_HGeom htab

MMG5_Point structure

MMG5_Info info

MMG5_Point structure

char *namein

Input mesh name

char *nameout

Output mesh name

The MMG5_Mesh structure contains arrays to all geometric entities used to represent the mesh. Each geometric entity has its own structure. Tetrahedra are represented using the MMG5_Tetra structure:

struct MMG5_Tetra

double qual

Quality of the element

MMG5_int v[4]

Vertices of the tetrahedron

MMG5_int ref

Reference of the tetrahedron

MMG5_int base

Description

MMG5_int mark

Used for delaunay

MMG5_int xt

Index of the surface ref MMG5_xTetra associated to the

tetrahedron (only for tetrahedra that are adjacent to surfaces)

MMG5_int flag

flag

uint16 tag

tag

The structure xtetra

The mesh contains certain tetrahedra that bear particular information, notably because one or several of their faces pertain to the surface part of the mesh.

If pxt is of type pxtetra

• For \(i=0,\ldots,3\), pxt->ftag[i] is the tag of the \(i^{\text{th}}\) face of the tetrahedron.

• For \(i=0,\ldots,3\), pxt->ref[i] is the reference of the \(i^{\text{th}}\) face of the tetrahedron.