A hybrid metaheuristic method for solving resource constrained project scheduling problem

Resource constrained project scheduling problem (RCPSP) is a renowned variant of the scheduling problem. RCPSP is very important in production and management but computationally hard. It is widely used in many fields like job shop scheduling, flow shop scheduling, transactional planning, wireless communication etc. The objective of solving RCPSP is to obtain minimum makespan maintaining all constraints. There are some exact, approximate, heuristic and metaheuristic algorithms which were proposed to solve this problem. RCPSP is an NP-hard problem. Chemical reaction optimization (CRO) is a population based metaheuristic method to solve such problems and it shows better performance comparing with some other existing algorithms. CRO explores the large search space both locally and globally using its four operators. Genetic algorithm (GA) is also a nature inspired algorithm which is used to solve various optimization problems. In this paper, we are proposing a hybrid metaheuristic approach that integrates chemical reaction optimization (CRO) and genetic algorithm (GA) named CRO-GA to solve RCPSP. We have redesigned the basic operators of CRO and GA to find out the solutions. An additional operator called priority based selection operator is used in CRO to adjust with GA. Our proposed method is compared with other related approaches such as adaptive particle swarm optimization (A-PSO), multi agent optimization algorithm (MAOA), artificial bee colony (ABC), genetic algorithm (GA) which are state of the art for the RCPSP. The experimental results show that our proposed methodology gives better results than other existing algorithms to solve RCPSP with less computational time.