Interpolation on a Triangle

**TRIANGLE_INTERPOLATE**
is a MATLAB library which
demonstrates some simple techniques for interpolating data on a triangle.

In the most common case, the value of a quantity is known at the vertices of a triangle, and a reasonable interpolated value is desired at some point p in the interior of that triangle. This can be done by linear interpolation.

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

**TRIANGLE_INTERPOLATE** is available in
a FORTRAN90 version and
a MATLAB version and
a Python version.

FEM_BASIS, a MATLAB library which can define basis functions for the finite element method (FEM) for any degree in an M-dimensional simplex (1D interval, 2D triangle, 3D tetrahedron, and higher dimensional generalizations.)

GEOMETRY, a MATLAB library which performs geometric calculations in 2, 3 and N dimensional space.

TOMS886, a MATLAB library which defines the Padua points for interpolation in a 2D region, including the rectangle, triangle, and ellipse, by Marco Caliari, Stefano de Marchi, Marco Vianello. This is a version of ACM TOMS algorithm 886.

TRIANGLE_ANALYZE, a MATLAB program which reads a triangle defined in a file, and uses the triangle_properties() library to compute angles, area, centroid, circumcircle, edge lengths, incircle, orientation, orthocenter, and quality.

TRIANGLE_FEKETE_RULE, a MATLAB library which defines Fekete rules for quadrature or interpolation over the interior of a triangle in 2D.

TRIANGLE_GRID, a MATLAB library which computes a grid of points over the interior of a triangle in 2D.

TRIANGLE_HISTOGRAM, a MATLAB program which computes histograms of data on the unit triangle in 2D.

TRIANGLE_PROPERTIES, a MATLAB library which can compute properties, including angles, area, centroid, circumcircle, edge lengths, incircle, orientation, orthocenter, and quality, of a triangle in 2D.

- r8vec_uniform_01.m, returns a unit pseudorandom R8VEC.
- timestamp.m, prints the current YMDHMS date as a timestamp;
- triangle_area.m, returns the area of a triangle in 2D;
- triangle_interpolate_linear.m, uses linear interpolation based on values at the triangle vertices.
- triangle_interpolate_linear_test.m
- triangle_interpolate_linear.png, a plot of a sample interpolation, involving red, blue and green vertices.
- uniform_in_triangle_map1.m, returns random sample points from a triangle.

- triangle_interpolate_test.m, calls all the tests;
- triangle_interpolate_test_output.txt, the output file;

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