TRIANGLE_IO
Read and Write TRIANGLE Files

TRIANGLE_IO is a FORTRAN90 library which can read or write some simple versions of some of the files used by Jonathan Shewchuk's triangle() program.

Licensing:

The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.

Languages:

TRIANGLE_IO is available in a C version and a C++ version and a FORTRAN90 version and a MATLAB version.

Related Data and Programs:

FEM_TO_TRIANGLE, a FORTRAN90 program which reads FEM files defining a 2D mesh of triangles, namely a file of node coordinates and a file of elements defined by node indices, and creates a corresponding pair of node and element files for use by Jonathan Shewchuk's triangle program.

POLY, a data directory which contains a description and examples of the POLY file format.

SHOWME, a C program which can display the POLY files uses as input to TRIANGLE, and the output files that define meshes and other objects.

TRIANGLE, a C program which computes Voronoi diagrams and Delaunay triangulations, and creates and manipulates files that can be displayed by SHOWME.

TRIANGLE_DISPLAY, a MATLAB program which displays the nodes and elements of a triangulation on the MATLAB graphics screen, assuming the data has been stored in NODE and ELE files by the TRIANGLE program.

TRIANGLE_FILES, a data directory of examples of files used by the triangle and showme programs.

TRIANGLE_TO_FEM, a FORTRAN90 program which reads the NODE and ELE files created by triangle() to describe a triangular mesh, and writes a corresponding pair of node and element files in the 2D FEM format.

TRIANGLE_TO_MEDIT, a FORTRAN90 program which reads the NODE and ELE files created by triangle() to describe a triangular mesh, and writes a corresponding MESH file for input to medit().

TRIANGLE_TO_XML, a FORTRAN90 program which reads the NODE and ELE files created by triangle() to describe a triangular mesh in 2D, and writes out a corresponding XML mesh file for use by DOLFIN or FENICS.

Source Code:

• triangle_io.f90, the source code.

Examples and Tests:

• triangle_io_test.f90 a sample calling program.
• triangle_io_test.txt, the output file.
• example.ele, an example ".ele" file created by the program.
• example.node, an example ".node" file created by the program.

List of Routines:

• CH_CAP capitalizes a single character.
• CH_EQI is a case insensitive comparison of two characters for equality.
• CH_TO_DIGIT returns the integer value of a base 10 digit.
• ELEMENT_DATA_EXAMPLE returns the element information for the example.
• ELEMENT_DATA_READ reads the data from an element file.
• ELEMENT_SIZE_EXAMPLE returns the element size information for the example.
• ELEMENT_SIZE_READ reads the header information from an element file.
• ELEMENT_WRITE writes a TRIANGLE ".ele" file.
• GET_UNIT returns a free FORTRAN unit number.
• I4MAT_COPY copies an I4MAT.
• I4MAT_TRANSPOSE_PRINT prints an I4MAT, transposed.
• I4MAT_TRANSPOSE_PRINT_SOME prints some of the transpose of an I4MAT.
• NODE_DATA_EXAMPLE returns the node information for the example.
• NODE_DATA_READ reads the data from a node file.
• NODE_SIZE_EXAMPLE returns the sizes of node information for the example.
• NODE_SIZE_READ reads the header information from a node file.
• NODE_WRITE writes a TRIANGLE ".node" file.
• R8MAT_COPY copies an R8MAT.
• R8MAT_TRANSPOSE_PRINT prints an R8MAT, transposed.
• R8MAT_TRANSPOSE_PRINT_SOME prints some of an R8MAT, transposed.
• S_TO_I4 reads an I4 from a string.
• S_TO_I4VEC reads an I4VEC from a string.
• S_TO_R8 reads an R8 from a string.
• S_TO_R8VEC reads an R8VEC from a string.
• TIMESTAMP prints the current YMDHMS date as a time stamp.

You can go up one level to the FORTRAN90 source codes.