These are AMPL scripts for nonlinear optimization problems from the paper:

 H. Maurer and H. D. Mittelmann, Optimization Techniques for Solving Elliptic
 Control Problems with Control and State Constraints.
 Part 1: Boundary Control, Comp. Optim. Applic. 16, 29-55 (2000).

Characteristics of the problems
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Notation: RHS:   right-hand side of PDE
          BC:    boundary condition
          CC/SC: control/state constraints
          NOREG: no regularization (zero factor with integral over control)
          OP:    nature of optimization problem

All examples:    Boundary Control, neg. Laplacian as differential op.
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  Examples 1-4:  Dirichlet BC, OP: convex QP
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Example 1: RHS constant, CC/SC both active

Example 2: as Ex. 1, except NOREG, CC/SC not active, singular control

Example 3: as Ex. 1 but tighter CC/SC

Example 4: as Ex. 3, except NOREG, bang-bang control


  Examples 5-8:  Neumann/Mixed BC
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Example 5: Nonlinear BC, RHS zero, CC/SC both active. OP: quad. eq. constraints

Example 6: similar to Ex. 1, except NOREG, bang-bang control

Example 7: RHS cubic, BC linear, Ginzburg Landau model, OP: NLP

Example 8: same as Ex. 7, except NOREG, bang-bang control