Section Calculation Modes::Optimal Control
If OCTTargetOperator = oct_tg_density, then one must supply the target density that should be searched for. This one can do by supplying a string through the variable OCTTargetDensity. Alternately, give the special string "OCTTargetDensityFromState" to specify the expression via the block OCTTargetDensityFromState.
call parse_variable(namespace, 'OCTTargetDensity', "0", expression)