TRIANGULATION_NODE_TO_ELEMENT
Average Node Data to Create Element Data

TRIANGULATION_NODE_TO_ELEMENT, a MATLAB program which reads datafiles 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.

The program reads three data files:

• a node file, containing X, Y coordinates of points;
• an element file, containing a list of sets of three points making up each triangular element; (if this file does not exist, the program will generate the element data automatically).
• a node values file, containing the values of one or more data items at each node.

• an element values file, containing the values of the data, averaged over the nodes in each element.

Usage:

triangulation_node_to_element ( 'prefix' )

• 'prefix'_nodes.txt, lists the node coordinates;
• 'prefix'_elements.txt lists the indices of nodes that form elements (this file is optional, and if not supplied, the information will be generated internally);
• 'prefix'_values.txt contains the value assigned to each node.
• 'prefix'_element_values.txt will contain the values averaged over the nodes in each element.

Licensing:

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

Languages:

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

Related Data and Programs:

MESH_TO_XML, a MATLAB 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.

TRIANGULATION, a MATLAB library which carries out various operations on order 3 ("linear") or order 6 ("quadratic") triangulations.

TRIANGULATION_L2Q, a MATLAB program which reads information about a 3-node (linear) triangulation and creates data defining a corresponding 6-node (quadratic) triangulation;

triangulation_node_to_element_test

TRIANGULATION_ORDER1_DISPLAY, a MATLAB program which plots piecewise constant data associated with a triangulation;

TRIANGULATION_ORDER3_CONTOUR, a MATLAB program which can display a contour plot of scalar data defined on a triangulation of order 3.

TRIANGULATION_ORDER6_CONTOUR, a MATLAB program which can display a contour plot of scalar data defined on a triangulation of order 6.

TRIANGULATION_Q2L, a MATLAB program which reads information about a 6-node (quadratic) triangulation and creates data defining a corresponding 3-node (linear) triangulation;

Source Code:

• triangulation_node_to_element.m, the source code.
• timestamp.m prints the YMDHMS date as a timestamp.