@TechReport{	  it:2021-003,
  author	= {Ivo Dravins and Maya Neytcheva},
  title		= {On the Numerical Solution of State- and
		  Control-Constrained Optimal Control Problems},
  institution	= {Department of Information Technology, Uppsala University},
  department	= {Division of Scientific Computing},
  year		= {2021},
  number	= {2021-003},
  month		= apr,
  abstract	= {We consider the iterative solution of algebraic systems,
		  arising in optimal control problems, constrained by a
		  partial differential equation, with additional box
		  constraints on the state and the control variables, and
		  sparsity imposed on the control. A nonsymmetric two-by-two
		  block preconditioner is analysed and tested for a wide
		  range of problem, regularization and discretization
		  parameters. The constraint equation characterizes
		  convection-diffusion processes.}
}