*By Evalf, and other Nutils contributors*

officialLaplace

Solves Laplace's equation `Δu = 0`

on a unit square domain `Ω`

with
boundary `Γ`

, subject to boundary conditions:

```
u = 0 Γ_left
∂_n u = 0 Γ_bottom
∂_n u = cos(1) cosh(y) Γ_right
u = cosh(1) sin(x) Γ_top
```

This problem is constructed to contain all combinations of homogenous and
heterogeneous, Dirichlet and Neumann type boundary conditions, as well as to
have a known exact solution in `uexact = sin(x) cosh(y)`

.