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The varstack displays the current path in the search space
together with past and future alternatives.
Whenever a variable is selected for labelling, it is displayed
in this window in a new row that contains the following items:
- a coloured bar which represents the variable domain
- labelling depth, which denotes the number of variables
currently labelled,
and thus also the stack row number starting from zero
- variable identification; it is written in the format
MatrixName: Row.Column
The variable domain box displays the original variable domain,
current value of the variable,
previous values which have been tried and failed (maybe after
producing a solution and backtracking in the search
for another one) and remaining values which still have to be tried.
The whole bar width represents the original variable domain
and selected domain parts are represented by rectangles with
the appropriate width and position.
The colours have the following meaning (ordered with increasing darkness
when black-and white):
- white - values which have been removed from the original
variable domain before it was labelled
- gray - values which have been tried and failed.
- blue - values which still remain to be tried
- orange - the current variable domain (if not instantiated
after labelling it. This might be the case e.g.
when the domain is split into two parts.)
- red - the current variable value (if instantiated)
For example, after the sequence
X :: 0..10, X #< 8, grace_label(X)
and backtracking over the values 0, 1 and 2, the variable
domain will be displayed as follows:
Next: Basic Labelling
Up: Starting with Grace
Previous: Basic Control
Micha Meier
Tue Jul 2 10:07:34 MET DST 1996