Classical FEM framework to solve the Laplace equation over a unit square domain:
\nabla^2u = 0 \;,\; \forall (x,y)\in[0,1]\times[0,1]
The code is provided with the following example:
\forall (x,y)\in[0,1]\times[0,1]\;,
\begin{cases}
&u(x,0) &= &\sin(\pi x) \\[0.5em]
&u(x,1) &= &0 \\[0.5em]
&u(0,y) &= &0 \\[0.5em]
&u(1,y) &= &0
\end{cases},
which has analytical solution:
u(x,y) = \sin(\pi x)\left[\cos(\pi y) - \coth(\pi)\sinh(\pi y)\right]
The distribution of files is as follows: