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Grace has many features that assist the user
during the development of constraint programs:
- It allows to stop the execution at any time
and to inspect the current state, without having to compile
the program in a specific mode and without
any significant overhead.
- It displays the current domain of all or selected
variables as well as the path in the search space,
and the variable selected for labelling.
- The user can step through the execution
from labelling one variable
to the next one, or even from modifying one variable to another
during constraint propagation.
- The user can specify various stop conditions
and let the program run in its full speed until one of them is met.
The conditions can be the state of one or more variables,
reaching a specified step number or a solution,
reaching or failing a specified depth, ...
- Skipping to a particular step number,
be it backward of forward, is straightforward.
- The user can modify variables interactively
and see the immediate consequence of such modifications.
- Grace allows to move quickly in the search space
and to look for a solution in a man-machine cooperation.
- The user can easily experiment with a number
of predefined labelling strategies,
both for variable and value selection.
- Using the options mechanism, the user can customise
Grace to a large extent to the needs of the hardware and operating
system
and the program being developed.
- Grace is itself an ECLiPSe program which can be loaded
and used independently on other programs.
It can be switched on and off, without causing an overhead
when it is not used.
- Grace also provides a utility library which simplifies
the task of defining constraints over lists or matrices
of variables.
This on one hand simplifies the programming
task,
on the other hand it gives the user more flexibility
in experimenting with various models for a given problem.
Next: Constraint Programs
Up: Grace 1.0 User
Previous: Prologue
Micha Meier
Tue Jul 2 10:07:34 MET DST 1996