Data Matrix

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.

Figure 1: A typical data matrix view

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.

Basic Editing

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)

Figure 2: Editing a cell

• Double-click column header to edit column name (see Figure 3)

Figure 3: Renaming column

• Search and replace values in single column/all columns by right-clicking and selecting Replace values (see Figure 4)

Figure 4: Basic search and replace

• Re-order columns by clicking a column header and dragging the column left or right

• An entire column can be filled with a single value by right-clicking and selecting Fill with value (see Figure 5)

Figure 5: Fill column with values

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 6 and 7 display the options available by right-clicking row header and column.

Figure 6: Right-click the row header - options

Figure 7: Right-click column - options

Advanced Functionallity

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

It is also possible to plot a single column’s data against the row ID’s

• Right-click and select the Plot column option

To perform analysis of classifier performance (read more about the classifier performance analysis):

• Right-click and select the Classifier Performance option