The cost function measures the quality of the current schedule and
generally involves the weighted sum of penalties associated with
different types of constraint violations. Summing these penalties or
costs is not strictly necessary, provided that the components
(individual costs) can be combined in some fashion to reflect the
overall quality of the schedule.
Let C be the set of the given constraints. A <#364#>feasible<#364#> schedule
is defined as a schedule that satisfies the set of hard constraints
#tex2html_wrap_inline1666#, where #tex2html_wrap_inline1668#.
We consider the following as part of the abovementioned cost function:
- <#368#>Time period cost<#368#> includes the cost of class or classes
assigned to that period, (for example, the cost that result from
having a certain class and its lab scheduled in the same time period);
and cost of class spreading over the week and within each of the
weekdays.
- <#369#>Professor cost<#369#> includes the cost
incurred from assigning more classes than the maximum number taught
by that professor; cost from not having a long enough time interval
between classes taught by the same professor; and cost of assigning
to the same professor two or more classes that overlap in time.
- <#370#>Student cost<#370#> is the sum of various costs associated with
each student, such as eligibility criteria, number of classes taken,
and preferences and class time cost.
- <#371#>Distance cost<#371#> is obtained from the distance constraint.
- <#372#>Room size cost<#372#> is obtained from the room constraint.