Student Luch Break
The StudentLuchBreak additional criterion penalizes cases when there are two classes sharing students overlapping with the lunchtime that is one after the other with a break in between smaller than the requested lunch break. It creates a student lunch break conflict every time a student has two classes overlapping the lunch period (by default between 11:00 and 13:30) that have less than 30 minutes in between. While this approach is quite naive, it works surprisingly well, especially when most classes are longer than an hour.
On the Administration > Solver > Solver Parameters page, the StudentLuchBreak criterion must be added to the General.AdditionalCriteria parameter. For instance, you can put the following text:
at the end of the current Default value of the parameter (it contains a semicolon-separated list of classes).
With that, you should start seeing "Student lunch conflicts" property in the Best / Current Timetable solution information on the Solver page. But please note that it only shows the line when there is at least one student lunch conflict.
Other than that, you can create the following parameters (if you need to change the defaults).
StudentLunch.StartSlot=132 (lunch period start time, in 5 minute slots since midnight)
StudentLunch.EndStart=162 (lunch period end time, in 5 minute slits since midnight)
StudentLunch.Length=6 (minimal lenght of a lunch break, in the number of 5 minute slots)
Comparator.StudentLunchWeight (conflict weight, defaults to Comparator.StudentConflictWeight which is the weight of a student conflict)
Lunchtime is defined by StudentLunch.StartSlot and StudentLunch.EndStart properties (default is 11:00 am - 1:30 pm), with the lunch break of at least StudentLunch.Length slots (default is 30 minutes). The parameters are defined in time slots, one slot is 5 minutes and they start at midnight (132 is 11 am, that is (132 * 5) / 60). The weight of a lunch conflict (there is a conflict when there are two classes for a student overlapping the lunch period, that do not have enough time in between) is defined by Comparator.StudentLunchWeight parameter which defaults to the (ordinary) student conflict weight.
You can define a new solver parameter by clicking on the Add Solver Parameter button, e.g.: