Lib_VTK_IO_CON

CON interface definition for Lib_VTK_IO.

Source: src/third_party/VTKFortran/references/legacy/Lib_VTK_IO_CON.f90

Dependencies

Contents

• VTK_CON

Functions

VTK_CON

Function for saving mesh connectivity.

Function that must be used when unstructured grid is used, it saves the connectivity of the unstructured gird. @note The vector connect must follow the VTK-legacy standard. It is passed as assumed-shape array because its dimensions is related to the mesh dimensions in a complex way. Its dimensions can be calculated by the following equation: (dc = NC + \sum\limits_{i = 1}^{NC} {nvertex_i }) where (dc) is connectivity vector dimension and (nvertex_i) is the number of vertices of (i^{th}) cell. The VTK- legacy standard for the mesh connectivity is quite obscure at least at first sight. It is more simple analyzing an example. Suppose we have a mesh composed by 2 cells, one hexahedron (8 vertices) and one pyramid with square basis (5 vertices) and suppose that the basis of pyramid is constitute by a face of the hexahedron and so the two cells share 4 vertices. The above equation !> gives (dc=2+8+5=15). The connectivity vector for this mesh can be:

first cell

• connect(1) = 8 number of vertices of first cell
• connect(2) = 0 identification flag of (1^\circ) vertex of first cell
• connect(3) = 1 identification flag of (2^\circ) vertex of first cell
• connect(4) = 2 identification flag of (3^\circ) vertex of first cell
• connect(5) = 3 identification flag of (4^\circ) vertex of first cell
• connect(6) = 4 identification flag of (5^\circ) vertex of first cell
• connect(7) = 5 identification flag of (6^\circ) vertex of first cell
• connect(8) = 6 identification flag of (7^\circ) vertex of first cell
• connect(9) = 7 identification flag of (8^\circ) vertex of first cell

second cell

• connect(10) = 5 number of vertices of first cell
• connect(11) = 0 identification flag of (1^\circ) vertex of second cell
• connect(12) = 1 identification flag of (2^\circ) vertex of second cell
• connect(13) = 2 identification flag of (3^\circ) vertex of second cell
• connect(14) = 3 identification flag of (4^\circ) vertex of second cell
• connect(15) = 8 identification flag of (5^\circ) vertex of second cell

Note that the first 4 identification flags of pyramid vertices as the same of the first 4 identification flags of the hexahedron because the two cells share this face. It is also important to note that the identification flags start form $0$ value: this is impose to the VTK standard. The function VTK_CON does not calculate the connectivity vector: it writes the connectivity vector conforming the VTK standard, but does not calculate it. The vector variable cell_type must conform the VTK-legacy standard (see the file VTK-Standard at the Kitware homepage). It contains the type of each cells. For the above example this vector is:

first cell

cell_type(1) = 12 hexahedron type of first cell

second cell

cell_type(2) = 14 pyramid type of second cell

Returns: integer(kind=I4P)

function VTK_CON(NC, connect, cell_type, cf) result(E_IO)

Arguments

Name	Type	Intent	Attributes	Description
NC	integer(kind=I4P)	in		Number of cells.
connect	integer(kind=I4P)	in		Mesh connectivity.
cell_type	integer(kind=I4P)	in		VTK cell type.
cf	integer(kind=I4P)	in	optional	Current file index (for concurrent files IO).