... For CFHT scheduling, the input data was provided in a tabular text file with each program defined in a row and each column corresponding to a parameter. ... An additional input is a description of the telescope instrumentation (e.g. instruments and associated telescope foci) and constraints on instrument changes (e.g. some instrument changes may require a half-day or more of ``down time'' or a limit on the total number of upper-end changes in a semester). miller@ . ...