triangulation_t3_to_t4, a MATLAB code which reads information describing a triangulation of a set of points using 3-node "T3" triangles, and creates a 4-node "T4" triangulation.
The same number of triangles are used, but each triangle is given one extra node at the centroid. The coordinates of these nodes are determined by averaging the coordinates of the vertices of the triangles.
The input and output files use the simple TABLE format; comment lines begin with a "#" character. Otherwise, each line of the file contains one set of information, either the coordinates of a node (for a node file), or the indices of nodes that make up a triangle, (for a triangle file).
The input file prefix_nodes.txt contains the node information for the 3-node triangulation. Each data line contains the X and Y coordinates of a single node.
The input file prefix_elements.txt contains the triangle information for the 3-node triangulation. Each line contains the indices of three nodes that form a triangle, in counterclockwise order.
The output file prefix_t4_nodes.txt contains the node information for the 4-node triangulation. It begins with the node information from prefix_nodes.txt, followed by the coordinates of the new nodes.
The output file prefix_t4_triangles.txt contains the triangle information for the 4-node triangulation. There are exactly as many triangles as before, but now each triangle uses four nodes. Each line of the file contains the indices of 4 nodes that form the triangle. The first three indices are the vertices, in counterclockwise order. The fourth index is the centroid node..
triangulation_t3_to_t4 ( 'prefix' )where 'prefix' is the common filename prefix:
The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.
triangulation_t3_to_t4 is available in a C++ version and a FORTRAN90 version and a MATLAB version.
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triangulation_refine, a MATLAB code which reads data defining a triangulation, replaces each triangle by four congruent smaller ones, and writes the new triangulation information to a file.
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