Prototyping CLP(FD) Tracers: a Trace Model and an Experimental Validation Environment

TL;DR

This paper introduces a novel trace model for CLP(FD) constraint solving, along with an experimental environment, enabling better visualization and analysis of logic program execution, which facilitates tool development and understanding.

Contribution

It presents the first trace model for CLP(FD), along with an instrumented meta-interpreter, to support execution analysis and visualization tools.

Findings

The trace model captures essential execution information.

The instrumented meta-interpreter validates the model.

The model supports building useful execution views.

Abstract

Developing and maintaining CLP programs requires visualization and explanation tools. However, existing tools are built in an ad hoc way. Therefore porting tools from one platform to another is very difficult. We have shown in previous work that, from a fine-grained execution trace, a number of interesting views about logic program executions could be generated by trace analysis. In this article, we propose a trace model for constraint solving by narrowing. This trace model is the first one proposed for CLP(FD) and does not pretend to be the ultimate one. We also propose an instrumented meta-interpreter in order to experiment with the model. Furthermore, we show that the proposed trace model contains the necessary information to build known and useful execution views. This work sets the basis for generic execution analysis of CLP(FD) programs.