This chapter describes the Decision Table Visualizer's data and configuration files. The *.dtableviz files contain a schema and an optional history section, and the *.data files contain the data. The format of these two files is almost exactly that described in Chapter 6, “Flat File Support for MineSet.”

The Decision Table Visualizer's *.dtableviz file must contain a schema of the following form: some number of columns of type string or enum; followed by a float column containing the weight of records; followed by a vector column, indexed by an enum containing possible classes, and containing the proportion of the weight of records in each class. The *.dtableviz and *.data files are automatically generated by the Tool Manager, and you should not normally need to modify them.

The schema in the *.dtableviz file uses two extra keywords that are not present in other schemas. They are auto, and nominal. The Decision Table Visualizer must be able to differentiate between different types of enums. For example, enums that are automatically rendered discrete by mining are handled differently in drill through than enums that are binned by the user in the Tool Manager. Therefore, the keyword auto is used to distinguish columns that have been binned by mining.

The label may be a binned column or a string column. Either way it appears as an enum in the schema, so that the final probs[] column can be indexed by it. If the label is string valued, the enum keyword is predicated with nominal to distinguish it.

The following is an example configuration file created from the adult dataset:

MineSet
input {
     file "adult-tmbin-dtab.dtableviz.data";
     enum string `hours_per_week_bin_k`{"- 20", "20-28", "28-36",
"36-44", "44-52", "52-60", "60+"};
     enum `hours_per_week_bin_k``hours_per_week_bin`;
     auto enum string `gross_income_k`{"- 9598", "9598-14579",
"14579-24794.5", "24794.5-24806", "24806-29606", "29606-42049.5",
"42049.5-46306.5", "46306.5-64885", "64885+"};
     enum `gross_income_k``gross_income`;
     auto enum string `final_weight_k`{"- 223033", "223033+"};
     enum `final_weight_k``final_weight`;
     float `weight`;
     nominal enum string `label`{"Female  ", "Male    "};    
# the label values
     float `probs[]`[ enum `label`]; # and probabilities
}
history {
:
:
}

In this example, the name of the data file is adult-tmbin-dtab.dtableviz.data, and # denotes a comment line. The first three columns are attributes from the data. The first one, hours_per_week_bin was binned by the user using the Tool Manager. The second two, gross_income and final_weight were binned automatically by the mining algorithm. Note the use of the auto keyword in their enum definitions. The fourth column gives the weight of records that have the values given by the first three columns.

The last column, probs[], is a vector-valued column that gives the probability of each class. It is computed by dividing the number of records for each class by the value in the weight column. The sum of the entries of this vector must add to 1. The definition of the index label includes the keyword nominal to show that the class values are not numeric, and therefore do not have an implied ordering. The nominal keyword would not be present had the label been a binned numeric attribute.