Gentra4cp: A Generic Trace Format for Constraint Programming

Abstract

Several debugging tools have been designed for constraint programming (CP). There is no ultimate tool, that satis.es all the needs, but rather a set of complementary tools. Most of them are dynamic tools. They collect data from the execution and produce abstract views of this execution, for instance a search-tree, the evolution of some domains, or an application-specific display.

So far, there are two issues concerning CP debugging tools. Firstly, each tool is dedicated to a given platform: there is no sharing of tools among the CP platforms, whereas most of solvers are based on the same techniques. Secondly, the extraction of execution data requires the solver to be instrumented. Such instrumentation is tedious and needs to access the solver code. We propose to address those two issues by means of a generic trace format which allows the execution to be described as a sequence of elementary events reflecting the behavior of the search procedure and the propagation process. The tools can then pick in the trace the data they need.

This work has been partly supported by the French RNTL OADymPPaC project.