OPTIMIZATION

After the initial evaluation of the dependencies and the index set-up, a further optimizing step is taken. By analyzing the indices described above, the following three indices can be created:

1. *needed* for each index number (which corresponds to a rule), record a list of index numbers (which correspond to rules) that could satisfy needed constraints.
2. *need-filler* for each index number, records a list of index numbers that need a constraint supplied by the corresponding rule.
3. *eff-failers* for each index number, records a list of index numbers that must be failed if this rule is used due to conflicts with the rule's effects.
4. *dep-failers* for each index number, records a list of index numbers that must be failed if this rule is used due to conflicts with the rule's DEP preconditions.

For relation-20, the following information is recorded.

• *EFF-FAILERS*
• *DEP-FAILERS*
• *NEED-FILLERS*
• *NEEDED*