SINUSOID - A problem with sinusoidal solution

The SINUSOID problem has as exact solution U(X,Y)=SIN(PI*X)*SIN(PI*Y). It uses a 13 by 13 grid on [0,1] x [0,1]; zero Dirichlet boundary conditions are applied. Only triangular elements are used.

Even though we don't use quadrilateral elements and Neumann boundary conditions, we include dummy files for that data, because the code will look for them.

Files you may copy include:

• coordinates.dat, the spatial coordinates of the nodes.
• dirichlet.dat, the edges of the region along which Dirichlet boundary conditions are specified. Edges are denoted by pairs of nodes, and the nodes should be listed in their counterclockwise order around the region.
• elements3.dat, defines the triangular elements by listing the indices of their vertices. The vertices should be listed in counterclockwise order.
• elements4.dat, defines the quadrilateral elements by listing the indices of their vertices. The vertices should be listed in counterclockwise order.
• neumann.dat, the edges of the region along which Neumann boundary conditions are specified. Edges are denoted by pairs of nodes, and the nodes should be listed in their counterclockwise order around the region.
• f.m, evaluates the right hand side of Laplace's equation.
• g.m, evaluates the Neumann boundary conditions.
• u_d.m, evaluates the Dirichlet boundary conditions.
• sinusoid.jpg, a JPEG image of the 3D graphical output.