The data matrix is HUGINs tool for inspecting and manipulating data sets. Data is displayed using a grid like interface very similar to what most users know from Excel, see Figure 1. The data matrix is available in places dealing with data files, including the learning- and EM wizards, the data frame functionallity and other places dealing with data.
The leftmost column is the row header which display row numbers, first row is 0 as rows are zero-indexed. The top header display column names, when using data with a HUGIN model the columns represent nodes.
The data set can be inspected using the data matrix. Although HUGIN is not EXCEL, some basic editing of data items can be performed:
Use Mouse pointer or cursor-keys to navigate about
Double-click a cell to edit the data item (see Figure 2)
Double-click column header to edit column name (see Figure 3)
Search and replace values in single column/all columns by right-clicking and selecting Replace values (see Figure 4)
Re-order columns by clicking a column header and dragging the column left or right
Rows and columns can be edited as well:
Create/delete row by right-clicking row header and selecting insert- or delete row
Create/delete column by right-clicking column header and selecting insert- or delete column
Figures 5 and 6 display the options available by right-clicking row header and column.
Columns containing numerical data, exclusively, can be discretized into a set of intervals by launching the discretizer (read more about the discretization features):
Right-click a column containing numerical data and select Discretize values
More elaborate modifications are performed using batch preprocessing (read more about the preprocessing (Data Processing) features):
Right-click and select the Data Processing option
To inspect properties of the data set use the data set analysis functionallity (read more about the data analysis features):
Right-click and select the Analysis option
To perform analysis of classifier performance (read more about the classifier performance analysis):
Right-click and select the Classifier Performance option