5.9.1 Forward Chaining History

Figure 5.12 KnowledgeWorks Forward Chaining History

The Forward Chaining History may be viewed by choosing KnowledgeWorks > FC History . This displays the rules which the forward chaining engine has fired. The left pane lists sequentially the contexts which have been executed, with the cycle number in which they were entered. These can be clicked on to show in the right pane, the history for that context. The rules in it are listed down the left, and the cycle numbers along the top, forming a two dimensional grid.

Each position in the grid indicates the status of the rule in that cycle. A coloured box indicates that the rule fired. A half-coloured box indicates that the rule fired, but that the invocation of the backward chainer on the right-hand side failed at some point. There can only be one coloured or half-coloured box per cycle. An outlined box indicates that the rule was in the conflict set but was not chosen to fire. Absence of any icon indicates that the rule was not even in the conflict set.

If the forward chaining history is displayed while a rule is executing (for example, while the rule is being single stepped) a half-coloured box is displayed as execution is not complete.

The Works > Rule menu can be used in the same way as in the Rule Browser, described in The Rule Browser. It applies to the selected rule in the FC Cycles pane.

This tool is not available when debugging is turned off.


KnowledgeWorks and Prolog User Guide - 4 Apr 2005