| $ c $ | $ 100 $ | $ 10 $ | $ 1 $ | $ -1 $ | $ -10 $ | $ -15 $ |
| $ \mu_{max} $ | $ 1.00476 $ | $ 1.04975 $ | $ 1.43204 $ | $ 4.24815 $ | $ 2.69623e+7 $ | $ 4.70925e+12 $ |
In this paper, we study the conditioning of optimal control problems constrained by linear parabolic equations with Neumann boundary conditions. While we concentrate on a given end-time target function, the results hold when the target function is given over the whole time horizon. When implicit time discretization and conforming finite elements in space are employed, we show that the reduced problem formulation has condition numbers which are bounded independently of the discretization level in arbitrary space dimension. In addition, we propose the all-at-once approach, i.e., for the first-order conditions of the unreduced system a preconditioner based on work by Greif and Schötzau, which provides bounds on the eigenvalue distribution independently of the discretization level. Numerical experiments demonstrate the obtained results and the efficiency of the suggested preconditioners.
| Citation: |
Table 1.
Maximal eigenvalues of
| $ c $ | $ 100 $ | $ 10 $ | $ 1 $ | $ -1 $ | $ -10 $ | $ -15 $ |
| $ \mu_{max} $ | $ 1.00476 $ | $ 1.04975 $ | $ 1.43204 $ | $ 4.24815 $ | $ 2.69623e+7 $ | $ 4.70925e+12 $ |
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The maximal eigenvalues of