To start the user interface for RGEN type RGEN & at the UNIX
command prompt or invoke it from the main menu of the system. The
window in Figure 
is then shown on the screen.
Selecting ``Quit'' will exit the program. ``Ok'' will run the program
with options as chosen in the window, and ``Help'' displays a window
explaining all options.
Files
After having started the program, the name of some files should be
given. A table file which contains the data to be searched for
regularities and a dictionary file are necessary. These two files
should both be in RSES format
, and could be
generated by using the program RSES
or something else. The name of the files are entered in
the corresponding fields in the window.
Entering the name of the rule file is optional. If no file name is
entered, the generated rules are instead written to standard out.
Threshold Value
A threshold value specifies which rules to keep. If e.g. a threshold
value of 0.5 is entered, rules which are correct for less than
50% of the objects they apply to are discarded.
Method for Generation Rules
RGEN may create two kind of rules. Non-prioritized, or Theorist as
they are called in [Hju96], are default rules with
blocks. Prioritized rules does not have blocks, and all
duplicated are created at all nodes due to joining.
Type of Descriptions
Two types of descriptions which may be used are Minimal
descriptions and Class descriptions.
Minimal descriptions will make sure that the descriptions for each
rule are minimal and does not contain unnecessary attributes.
Maximum Reducts
This option specifies the maximum reducts which shall be found in each
discernibility function. If the field is blank or 0, all reducts are found.
Traverse Lattice Only
This option is not for normal use, but rather for speed analysis. If
selected, no rules will be generated, but the algorithm will traverse
the lattice in the usual manner, see Chapter . Actually, a version of the program
called rgen_traverse_only is started instead of the usually
rgen.