Two neighbourhood approaches to the timetabling problem

It is well known that any search algorithm needs for certain parts to be problem specific. It is very important the way these parts are implemented. A fine tuning of parameters will never balance a bad definition of the solution set, of the neighbourhood or the cost function. In this paper we try to compare two well known neighbourhood operators applied to the timetabling problem. Tests were made using real data from three Portuguese schools of different size and complexity. We then observed that the application of the correct neighbourhood operator is essential to the success of the search algorithm.