TRIANGULATION_TRIANGLE_NEIGHBORS is a C program which computes the three neighboring triangles of each triangle in a triangulation.
The user supplies a node file and a triangle file, containing the coordinates of the nodes, and the indices of the nodes that make up each triangle. Either 3-node or 6-node triangles may be used.
The program reads the data, computes the triangle neighbor information, and writes out the information to a file. In cases where one side of a triangle has no triangle neighbor, a value of -1 is assigned.
The triangle neighbor array is useful if the triangulation has to be searched to find the triangle containing a given point. It is also useful when analyzing the bandwidth of the adjacency matrix, or of a finite element matrix derived from the triangulation.
triangulation_triangle_neighbors prefixwhere 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_TRIANGLE_NEIGHBORS is available in a C version and a C++ version and a FORTRAN90 version and a MATLAB version.
MESH_BANDWIDTH, a C++ program which returns the geometric bandwidth associated with a mesh of elements of any order and in a space of arbitrary dimension.
MESH_TO_XML, a C program which reads information defining a 1D, 2D or 3D mesh, namely a file of node coordinates and a file of elements defined by node indices, and creates a corresponding XML file for input to DOLFIN or FENICS.
NEIGHBORS_TO_METIS_GRAPH, a C++ program which reads a triangle mesh neighbor file created by TRIANGULATION_TRIANGLE_NEIGHBORS and writes a modified version of the same data suitable for input to the mesh partitioning program METIS.
RCM, a C++ library which carries out reverse Cuthill-McKee computations.
TABLE_DELAUNAY, a C++ program which triangulates a set of nodes whose coordinates are stored in a file.
TET_MESH_RCM, a FORTRAN90 library which applies the reverse Cuthill-McKee reordering to a tetrahedral mesh of nodes in 3D.
TRIANGLE, a C program which computes a triangulation of a geometric region.
TRIANGULATION, a C library which performs various operations on order 3 (linear) or order 6 (quadratic) triangulations.
TRIANGULATION_BOUNDARY_NODES, a C++ program which reads data defining a triangulation, determines which nodes lie on the boundary, and writes their coordinates to a file.
TRIANGULATION_DISPLAY_OPENGL, a C++ program which reads files defining a triangulation and displays an image using Open GL.
TRIANGULATION_HISTOGRAM, a C++ program which computes histograms of data over a triangulation.
TRIANGULATION_L2Q, a C++ program which reads data defining a 3-node triangulation and generates midside nodes and writes out the corresponding 6-node triangulation.
TRIANGULATION_NODE_TO_ELEMENT, a C program which reads files describing a set of nodes, their triangulation, and the value of one or more quantities at each node, and outputs a file that averages the quantities for each element. This operation in effect creates an "order1" finite element model of the data.
TRIANGULATION_ORDER3, a directory which contains a description and examples of order 3 triangulations.
TRIANGULATION_ORDER6, a directory which contains a description and examples of order 6 triangulations.
TRIANGULATION_ORIENT, a C++ program which reads data defining a triangulation, makes sure that every triangle has positive orientation, and if not, writes a corrected triangle file.
TRIANGULATION_PLOT, a C++ program which reads data defining a triangulation and creates a PostScript image of the nodes and triangles.
TRIANGULATION_Q2L, a C++ program which reads data defining a 6-node triangulation, and subdivides each triangle into 4 3-node triangles, writing the resulting triangulation to a file.
TRIANGULATION_QUAD, a C++ program which estimates the integral of a function over a triangulated region.
TRIANGULATION_QUALITY, a C++ program which reads data defining a triangulation and computes a number of quality measures.
TRIANGULATION_RCM, a C++ program which can reorder the nodes of a triangulation so that the bandwidth of the associated adjacency matrix is reduced.
TRIANGULATION_REFINE, a C++ program which reads data defining a triangulation, replaces each triangle by four congruent smaller ones, and writes the new triangulation information to a file.
TRIANGULATION_SVG, a C program which creates a Scalable Vector Graphics (SVG) image of a triangulation, which can be displayed by a web browser.
TRIG_TO_NEIB, a C program which reads "NODE" and "ELE" files (a format prescribed by triangle) describing a triangulation, and produces a file defining the neighbor triangles of each element; the program can also produce information about the Voronoi diagram. The program is by Lili Ju.
BOX3 is a triangulation of order 3:
BOX6 is a triangulation of order 6:
You can go up one level to the C source codes.