A Poisson Problem in a Region with Baffles

**FEM2D_POISSON_SPARSE_BAFFLE**
is a MATLAB library which
defines the geometry and other data for the "baffle" problem,
a rectangular region with 13 hexagonal baffles.
The problem is suitable for solution by **fem2d_poisson_sparse**.

The region is a rectangle with lower left corner (0.0,1.0) and upper right corner (12.0,7.0). The mesh was created using MESH2D, with a maximum element size of 0.5. The mesh comprises 512 nodes and 874 elements.

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

**FEM2D_POISSON_SPARSE_BAFFLE** is available in
a C++ version and
a FORTRAN90 version and
a MATLAB version.

FEM2D_POISSON_SPARSE, a MATLAB program which solves the steady (time independent) Poisson equation on an arbitrary 2D triangulated region using MATLAB's sparse solver.

FEM2D_POISSON_SPARSE_ELL, a MATLAB library which defines the geometry of an L-shaped region, as well as boundary conditions for a given Poisson problem, and is called by fem2d_poisson_sparse as part of a solution procedure.

FEM2D_POISSON_SPARSE_LAKE, a MATLAB library which defines the geometry of a lake-shaped region, as well as boundary conditions for a given Poisson problem, and is called by fem2d_poisson_sparse as part of a solution procedure.

TRIANGULATION_ORDER3_CONTOUR, a MATLAB program which makes a contour plot of scattered data, or of data defined on an order 3 triangulation. In particular, it can display contour plots of scalar data output by fem2d_poisson, fem2d_poisson_sparse or fem2d_poisson_cg.

- dirichlet_condition.m, the user-supplied routine to evaluate the boundary conditions;
- h_coef.m, the user-supplied routine to evaluate H(X,Y);
- k_coef.m, the user-supplied routine to evaluate K(X,Y);
- rhs.m, the user-supplied routine the right hand side;

- baffle_output.txt, the output file;
- baffle_nodes.txt, a text file containing a list, for each node, of its X and Y coordinates;
- baffle_nodes.png, a PNG image of the nodes;
- baffle_elements.txt, a text file containing a list, for each element, of the three nodes that compose it;
- baffle_elements.png, a PNG image of the elements;
- baffle_values.txt, a text file containing the solution at each node;
- baffle_values_pwl.png, a PNG image of the solution, using a piecewise linear interpolant, created by triangulation_order3_contour.
- baffle_values_smooth.png, a PNG image of the solution, using a smooth interpolant, created by triangulation_order3_contour.

You can go up one level to the MATLAB source code page.