Aims

In this tutorial we want to show how to use constraint and search tree visualization to understand and solve a number of performance debugging problems commonly found in finite domain constraint programs. Whenever faced with a performance debugging problem, we have to answer the following questions:

What is happening?

Why is it happening?

What can we do about it?

Methods

We will use the visualization tools available in the CHIP V5.2 system, some of which have been developed inside the DiSCiPl Esprit project.

Searchtree Visualization

The search tree tool shows the form of the search tree and the information about the state of the constraint system at each node.

Constraint Visualization

These tools show individual global constraints and visualize the reasoning inside them.

Variable Visualization

These tools show sets of variables and their evolution during the search.

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