Neumann boundary

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1

Hi,

I understand that if we apply a Neumann boundary condition to the Poisson problem, there is no unique solution. I was wondering if there is a standard way to solve this problem in NGSolve by specifying a specific value for say a boundary point.

Best,
Dow

2

You can set one vertex dof to dirichlet with

fes.FreeDofs()[dofnr] = False

Then the problem should be solvable and the solution is 0 in that vertex.

Best
Christopher