ENH: added a general framework for normalization and setting targets

for all objective functions.

- The normalization is useful for practically all update methods dealing
with constraints (e.g. SQP, MMA). The normalization factor can be either
given explicitly or, if not given, will be the value of the objective
function in the first optimisation cycle.
- The target value is useful when using the objective as a constraint in
constrained optimisation problems (e.g. drag - dragTarget). It should
only be used with update methods that understand the value of the
constraint (e.g. SQP, MMA) but not when the objective in hand is the
only objective of the optimisation problem. In such a case, a squared
objective should be used (e.g. sqr(drag - dragTarget))

src/optimisation/adjointOptimisation/adjoint/objectives/objective/objective.H

@@ -72,6 +72,7 @@ protected:
         const word objectiveName_;
         bool computeMeanFields_;
         bool nullified_;
+        bool normalize_;
 
         //- Objective function value and weight
         scalar J_;
@@ -82,12 +83,21 @@ protected:
         //- Objective weight
         scalar weight_;
 
-        // Objective integration start and end times (for unsteady flows)
+        //- Normalization factor
+        autoPtr<scalar> normFactor_;
+
+        //- Target value, in case the objective is used as a constraint
+        //  Should be used in caution and with updateMethods than get affected
+        //  by the target value, without requiring a sqr (e.g. SQP, MMA)
+        scalar target_;
+
+        //- Objective integration start and end times (for unsteady flows)
         autoPtr<scalar> integrationStartTimePtr_;
         autoPtr<scalar> integrationEndTimePtr_;
 
-        // Contribution to field sensitivity derivatives
-        // Topology optimisation
+        //- Contribution to field sensitivity derivatives
+        //  Topology optimisation or other variants with
+        //  as many design variables as the mesh cells
         //~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
         autoPtr<volScalarField> dJdbPtr_;
@@ -248,6 +258,12 @@ public:
         //- Return the objective function weight
         scalar weight() const;
 
+        //- Is the objective normalized
+        bool normalize() const;
+
+        //- Normalize all fields allocated by the objective
+        virtual void doNormalization();
+
         //- Check whether this is an objective integration time
         bool isWithinIntegrationTime() const;