An integer programming model and heuristic algorithm for automatic scheduling in synchrotron facilities

This paper studies the automatic scheduling problem at the Canadian national synchrotron facility, Canadian Light Source (CLS). An automatic scheduling tool needs to be developed to replace the current manual approach for scheduling experiments on a set of beamlines - resources that generate high-intensity X-rays for use in many kinds of scientific experiments. We present an, Integer programming model for this scheduling activity by formulating it as a problem of unrelated and paralleled machines with partially overlapping capabilities. Furthermore a heuristic based approach is used that can save computation time by pruning the search space. Using realistic data sets generated using parameters made available by CLS, we compare the performance of the base line approach that uses ILOG CPLEX implementation of the Integer programming algorithm with one that uses heuristics. The results show that the heuristic approach runs faster than the base-line, but at the cost of producing a less optimal scheduling solution. An obvious advantage of the study presented in this paper is that the automatic scheduling can handle more scheduling conditions and constraints than humans are able to handle manually and can reach optimal solutions. As far as we know, this is the first attempt to propose an automatic scheduling approach for synchrotron facilities like CLS around the world.