The objective function specification is the specification of the measure we want to use to quantify the quality of the calibration. Since the only measurements we have in this example is the discharge in Branch1 at chainage 88827, we will use that for our objective function.
AutoCal minimises an aggregation of one or more objective functions. Each objective function may consist of several so-called output measures. For the present example one objective function is defined. We call it RMS_H and specify it as weighted sum.
As output measure we specify a measure that we call RMS_H_Branch1_87826. The measure is specified as the RMSE of the difference between the simulated water level and the measured water level in Branch1, chainage 87826. By specifying the weight as 1 and the function name as RMS_H the measure will contribute to the objective function called RMS_H with a weight of 1. Since we only have one output measure in the current example the concept of aggregation of objective functions constructed of several output measures may seem a little tedious. For other just slightly more complicated situations the concept proofs very powerful.