Poisson's equation on a three-dimensional rectangle
This application solves Poisson's equation in a three-dimensional rectangle with Dirichlet boundary condition in the form \[ \begin{align} -\Delta u(\mathbf{x}) &= f(\mathbf{x}),\quad \mathbf{x}\in\Omega=[0,a]\times[0,b]\times[0,c] \\ u(\mathbf{x}) &= 0,\quad \mathbf{x}\in \partial\Omega \end{align} \] where $\mathbf{x}$ is $(x,y,z)$. See Poisson's equation on rectangular domains I for more detail of the problem.
Data Input
The calculator requires a user to enter function $f(x,y,z)$ as f(x1,x2,x3) and the size of the 3D rectangle (a,b,c), where $3\leqslant a,b,c\leqslant 8$.