9. Tools for Search-Tree Visualisation: The APT Tool
Manuel Carro, Manuel V. Hermenegildo · 2000
The control part of the execution of a constraint logic program can be conceptually shown as a search-tree, where nodes correspond to calls, and whose branches represent conjunctions and disjunctions. This tree represents the search space traversed by the program, and has also a direct relationship with the amount of work performed by the program. The nodes of the tree can be used to display information regarding the state and origin of instantiation of the variables involved in each call. This depiction can also be used for the enumeration process. These are the features implemented in APT, a tool which runs constraint logic programs while depicting a (modied) searchtree, keeping at the same time information about the state of the variables at every moment in the execution. This information can be used to replay the execution at will, both forwards and backwards in time. These views can be