Lib_VTK_IO_CON_XML

CON_XML interface definition for Lib_VTK_IO.

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

Dependencies

Contents

• VTK_CON_XML

Functions

VTK_CON_XML

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-XML 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 = \sum\limits_{i = 1}^{NC} {nvertex_i }). Note that this equation is different from the legacy one. The XML connectivity convention is quite different from the legacy standard. As 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=8+5=13). The connectivity vector for this mesh can be:

first cell

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

second cell

• connect(9 ) = 0 identification flag of (1^\circ) vertex of second cell
• connect(10) = 1 identification flag of (2^\circ) vertex of second cell
• connect(11) = 2 identification flag of (3^\circ) vertex of second cell
• connect(12) = 3 identification flag of (4^\circ) vertex of second cell
• connect(13) = 8 identification flag of (5^\circ) vertex of second cell

Therefore this connectivity vector convention is more simple than the legacy convention, now we must create also the offset vector that contains the data now missing in the connect vector. The offset vector for this mesh can be:

first cell

• offset(1) = 8 => summ of nodes of (1^\circ) cell

second cell

• offset(2) = 13 => summ of nodes of (1^\circ) and (2^\circ) cells

The value of every cell-offset can be calculated by the following equation: (offset_c=\sum\limits_{i=1}^{c}{nvertex_i}) where (offset_c) is the value of (c^{th}) cell and (nvertex_i) is the number of vertices of (i^{th}) cell. The function VTK_CON_XML does not calculate the connectivity and offset vectors: it writes the connectivity and offset vectors conforming the VTK-XML standard, but does not calculate them. The vector variable cell_type must conform the VTK-XML standard (see the file VTK-Standard at the Kitware homepage) that is the same of the legacy standard. 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_XML(NC, connect, offset, cell_type, idx, 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.
offset	integer(kind=I4P)	in		Cell offset.
cell_type	integer(kind=I1P)	in		VTK cell type.
idx	integer(kind=I1P)	in	optional	Id offset to convert Fortran (first id 1) to C (first id 0) standards.
cf	integer(kind=I4P)	in	optional	Current file index (for concurrent files IO).

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