ABSTRACT The general m-machine permutation flowshop problem with the total flow-time objective is known to be NP-hard for m ≥ 2. The only practical method for finding optimal solutions has been branch-and-bound algorithms. In this paper, we present an improved sequential algorithm which is based on a strict alternation of Generation and Exploration execution modes as well as Depth-First/Best-First hybrid strategies. The experimental results show that the proposed scheme exhibits improved performance compared with the algorithm in . More importantly, our method can be easily extended and implemented with lightweight threads to speed up the execution times. Good speedups can be obtained on shared-memory multicore systems.
Cite this paper
C. Chung, J. Flynn and J. Sang, "Parallelization of a Branch and Bound Algorithm on Multicore Systems," Journal of Software Engineering and Applications, Vol. 5 No. 8, 2012, pp. 621-629. doi: 10.4236/jsea.2012.58071.
 C. Chung, J. Flynn and O. Kirca, “A Branch and Bound Algorithm to Minimize the Total Flow Time for m-Machine Permutation Flowshop Problems,” International Journal of Production Economics, Vol. 79, No. 3, 2002, pp. 185-196. doi:10.1016/S0925-5273(02)00234-7
 K. R. Baker, “Introduction to Sequencing and Scheduling,” Wiley, New York, 1974.
 J. N. D. Gupta and E. F. Stafford Jr., “Flowshop Scheduling Research after Five Decades,” European Journal of Operational Research, Vol. 169, No. 3, 2006, pp. 699-711. doi:10.1016/j.ejor.2005.02.001
 R. A. Dudek, S. S. Panwalker and M. L. Smith, “The Lessons of Flowshop Scheduling Research,” Operations Research, Vol. 40, No. 1, 1992, pp. 7-13.
 D. Gelenter and T. G. Crainic, “Parallel Branch and Bound Algorithms: Survey and Synthesis,” Operation Research, Vol. 2, 1994, pp. 1042-1066.
 E. Ignall and L. Schrage, “Application of the Branch and Bound Technique to Some Flow-Shop Scheduling Problems,” Operations Research, Vol. 13, No. 3, 1965, pp. 400-412.
 S. P. Bansal, “Minimizing the Sum of Completion Times of n Jobs Over m Machines in a Flowshop—A Branch, Bound Approach,” AIIE Transactions, Vol. 9, 1977, pp. 306-311. doi:10.1080/05695557708975160
 R. H. Ahmadi and U. Bagchi, “Improved Lower Bounds for Minimizing the Sum of Completion Times of n Jobs Over m Machines in a Flow Shop,” European Journal of Operational Research, Vol. 44, 1990, pp. 331-336.
 C.-F. Yu and B. W. Wah, “Efficient Branch-and-Bound Algorithms on a Two-Level Memory System,” IEEE Transactions on Software Engineering, Vol. 14, No. 9, 1988, pp. 1342-1356. doi:10.1109/32.6177
 M. O. Neary and P. Cappello, “Advanced eager scheduling for Java-Based Adaptive Parallel Computing,” Concurrency and Computation: Practice and Experience, Vol. 17, No. 7-8, 2005, pp. 797-819.
 K. Yu, J. Zhou, C. Lin and C. Tang, “Efficient Parallel Branch-and-Bound Algorithm for Constructing Minimum Ultrametric Trees,” Journal of Parallel and Distributed Computing, Vol. 69, No. 11, 2009, pp. 905-914.
 V. N. Rao and V. Kumar, “Parallel Depth-First Search on Multiprocessors—Part I: Implementation,” International Journal of Parallel Programming, Vol. 16, No. 6, 1987, pp. 479-499. doi:10.1007/BF01389000
 M. K. Yang and C. R. Das, “Evaluation of a Parallel Branch-and-Bound Algorithm on a Class of Multiprocessors,” IEEE Transactions on Parallel and Distributed Systems, Vol. 5, No. 1, 1994, pp. 74-86.
 B. Mans, T. Mautor and C. Roucairol, “A Parallel Depth First Search Branch and Bound Algorithm for the Quadratic Assignment Problem,” European Journal of Operational Research, Vol. 81, No. 3, 1995, pp. 617-628.
 J. Framinan, R. Leisten and R. Ruiz-Usano, “Comparison of Heuristics for Flow Time Minimisation in Permutation Flowshops,” Computers & Operations Research, Vol. 32, No. 5, 2005, pp. 1237-1254.
 Y. D. Kim, “Heuristics for Flowshop Scheduling Problems Minimizing Mean Tardiness,” Journal of Operational Research Society, Vol. 44, No. 1, 1993, pp. 19-28.
 C. Reeves, “Genetic Algorithms for the Operations Researcher,” INFORMS Journal of Computing, Vol. 9, No. 3, 1997, pp. 231-250.
 C. Ruiz and C. Maroto, “Comprehensive Review and Evaluation of Permutation Flowshop Heuristics,” European Journal of Operational Research, Vol. 165, 2005, pp. 479-494. doi:10.1016/j.ejor.2004.04.017
 C. N. Potts, “An Adaptive Branching Rule for the Permutation Flow-Shop Problem,” European Journal of Operational Research, Vol. 5, No. 1, 1980, pp. 19-25.
 B. Nichols, D. Buttlar and J. P. Farrel, “Pthreads Programming,” 1st Edition, O’Reilly & Associates, Inc., Sebastopol, 1996.
 K. A. Robbins and S. Robbins, “Practical UNIX Programming,” Prentice-Hall, Englewood Cliffs, 1996.
 E. Taillard, “Benchmarks for Basic Scheduling Problems,” European Journal of Operational Research, Vol. 64, No. 2, 1993, pp. 278-285.
 W. Press, S. Teukolsky, W. Vetterling and B. Flannery, “Numerical Recipes in C: The Art of Scientific Computing,” 2nd Edition, Chapter 7, Cambridge University Press, Cambridge, 1992.