Bulk and boundary contributions to the "Right-Hand-Side".

The ModelInterface allows for "Right-Hand-Side" functionals of the form

\[ \langle\rho\chi\sigma, \phi\rangle = \int_\Omega f\,\phi + \int_{\partial\Omega} g\,\phi + \langle\Psi,\phi\rangle \]

\(f\) is modelled by the ModelInterface::BulkForcesFunctionType, \(g\) is modelled by the ModelInterface::NeumannBoundaryFunctionType and the \(H^1\)-functional \(\Psi\) is modelled by ForcesFunctionalTraits::FunctionalType.

The default is to keep everything at zero.

Note

Functionals cannot not be operated on in a natural way by \(L^\infty\)-functions, only a vector space structure is "natural". Therefore ModelExpressions templates which model multiplication by functions will yield undefined results when applied to PDE-Models with a LinearFunctional as "right hand side" (maybe rejected by the compiler, maybe simply forming something which was most likely not intended).