The data type Z-LR is provided for zoning the optimisation parameter LERA. It defines a node-polyline for which a polyline-related leakage coefficient (data type LERA) is to be specified.

Note: Formally, it is necessary to assign a leakage coefficient with LERA in the model files to all polygon courses for which a leakage coefficient is to be optimised using inverse modelling.

• If a start parameter for the leakage coefficient of a Z-LR zone is specified in the parameter file, this parameter is optimised. A node-related leakage coefficient is calculated from the start parameter for the calculation of the direct problem by including the distance between the polyline nodes.

The additional leakage coefficient formally entered in the model files via LERA is irrelevant in this case.

• If no start parameter for the leakage coefficient of a Z-LR zone is specified in the parameter file, the leakage coefficient from the model file is used for this polyline.

Formulation of the inverse problems