TIGHT-TARDY PROGRESSIVE IDLING-FREE 1-MACHINE PREEMPTIVE SCHEDULING WITH JOB PRIORITY WEIGHTS BY HEURISTIC’S EFFICIENT JOB ORDER INPUT

Background. In setting a problem of minimizing total weighted tardiness by the heuristic based on remaining available and processing periods, there are two opposite ways to input data: job release dates given in either ascending or descending order. It was recently ascertained that scheduling few equal-length jobs is expectedly faster order, whereas 30 70 1.5 % 2.5 For number between roughly 90 250, order again results shorter computation times. case when have different lengths, significance much lower. On average, gives tiny advantage time. This decreases as increases. Objective. The goal ascertain whether significant using for lengths with priority weights. Job efficiency will be studied tight-tardy progressive idling-free 1-machine preemptive scheduling. Methods. To achieve said goal, computational study carried out purpose estimate averaged time both orders dates. First, estimated series problems. Then, each instance this series, weights, dates, due reversed making thus respective input, which well. Results. lower than without priorities. With assigning becomes further “dithered”, adding randomly scattered weights partially randomized believed give up 100 jobs. However, advantage, if any (being tinier random priorities), quickly vanishes Conclusions. better compose problems would closer priorities, where saved can counted hours. Even scattered, it recommended artificially “flatten” them. When artificial manipulations over periods impossible, use jobs, more although substantial benefits not expected case.