One of the few global objects in LUCAS is an instance of the
Parameters class called globals. This object provides an
interface between the GUI and the rest of LUCAS. All of the
information gathered from the user in the GUI is stored in GRASS
variables which are read by the Parameters object. This object stores
those values and makes them available for other objects, thus creating
a central repository for user-selected parameters. These values are
stored in a height-balanced AVL tree, implemented by the AVL class,
providing 
access of global parameters.
The Parameters class also reads the impacts file (Section A.2), which describes each impact module, and the scenario file (Section A.1) prescribed by the user via the GUI. All of the multinomial logit equation coefficients of the Transition Probability Matrix (TPM) are read in from the scenario file and stored in an internal matrix. This matrix is then used to construct the instance of the Composite class (Section 4.1.3) which in turn constructs its internal Matrix class object (Section 4.1.5). As each of the input map layers specified in the scenario file are read, a new OldRaster object (Section 4.1.7) is created, and an array of these objects is then used to initialize the Composite class.