A Poisson Problem in a Region with Baffles

**FEM2D_POISSON_CG_BAFFLE**
is a FORTRAN90 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_cg.

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

FEM2D_POISSON_CG, a FORTRAN90 program which solves Poisson's equation on a triangulated region, using the finite element method, sparse storage, and a conjugate gradient solver.

FEM2D_POISSON_CG_ELL, a FORTRAN90 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_cg as part of a solution procedure.

FEM2D_POISSON_CG_LAKE, a FORTRAN90 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_cg as part of a solution procedure.

- baffle.f90, the user-supplied routines to evaluate the right hand side, linear coefficient, and boundary conditions;
- 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 element mesh;

- baffle_output.txt, the output file;
- baffle_values.txt, a text file containing the solution U at each node (X,Y);

You can go up one level to the FORTRAN90 source code page.