Module 2 Dynamic Programming To accompany Quantitative Analysis for Management, 8e by Render/Stair/Hanna M2-1 © 2003 by Prentice Hall, Inc. Upper Saddle River, NJ 07458 Learning Objectives Students will be able to • Understand the overall approach of dynamic programming • Use dynamic programming to solve the shortest-route problem. • Develop dynamic programming stages. • Describe important dynamic programming terminology. • Describe the use of dynamic programming in solving knapsack problems. To accompany Quantitative Analysis for Management, 8e by Render/Stair/Hanna M2-2 © 2003 by Prentice Hall, Inc. Upper Saddle River, NJ 07458 Module Outline M2.1 Introduction M2.2 Shortest-Route Problem Solved by Dynamic Programming M2.3 Dynamic Programming Terminology M2.4 Dynamic Programming Notation M2.5 Knapsack Problem To accompany Quantitative Analysis for Management, 8e by Render/Stair/Hanna M2-3 © 2003 by Prentice Hall, Inc. Upper Saddle River, NJ 07458 Four Steps in Dynamic Programming • Divide the original problem into subproblems called stages. • Solve the last stage of the problem for all possible conditions or states. • Working backward from that last stage, solve each intermediate stage. • Obtain the optimal solution for the original problem by solving all stages sequentially. To accompany Quantitative Analysis for Management, 8e by Render/Stair/Hanna M2-4 © 2003 by Prentice Hall, Inc. Upper Saddle River, NJ 07458 Dynamic Programming George Yates Lakecity 4 Rice 1 Athens 10 miles 5 Brown 5 miles 3 7 2 6 10 miles Hope Georgetown To accompany Quantitative Analysis for Management, 8e by Render/Stair/Hanna M2-5 © 2003 by Prentice Hall, Inc. Upper Saddle River, NJ 07458 George Yates Stages Lakecity 4 Rice 1 Athens 10 miles 5 Brown 5 miles 7 3 Dixieville 2 6 10 miles Hope Georgetown Stage 3 Stage 2 Stage 1 To accompany Quantitative Analysis for Management, 8e by Render/Stair/Hanna M2-6 © 2003 by Prentice Hall, Inc. Upper Saddle River, NJ 07458 George Yates Stage 1 14 4 1 5 miles 10 miles 5 3 2 7 10 miles 6 2 To accompany Quantitative Analysis for Management, 8e by Render/Stair/Hanna M2-7 © 2003 by Prentice Hall, Inc. Upper Saddle River, NJ 07458 George Yates Stage 2 14 24 4 10 miles 5 8 1 5 miles 3 2 7 10 miles 12 To accompany Quantitative Analysis for Management, 8e by Render/Stair/Hanna 6 2 M2-8 © 2003 by Prentice Hall, Inc. Upper Saddle River, NJ 07458 George Yates Stage 3 24 4 14 10 miles 5 13 8 1 5 miles 7 3 2 10 miles 2 12 To accompany Quantitative Analysis for Management, 8e by Render/Stair/Hanna 6 M2-9 © 2003 by Prentice Hall, Inc. Upper Saddle River, NJ 07458 Dynamic Programming Terminology 1. Stage - A logical subproblem 2. State Variable - Possible condition 3. Decision Variable - Alternative 4. Decision Criterion - Problem objective 5. Optimal Policy - A set of decision rules 6. Transformation - Relationship between stages To accompany Quantitative Analysis for Management, 8e by Render/Stair/Hanna M2-10 © 2003 by Prentice Hall, Inc. Upper Saddle River, NJ 07458 Roller Transport Problem Items to be Shipped Item Weight Profit($) Number Available 1 1 3 6 2 4 9 1 3 3 8 2 4 2 5 2 The Relationship Between Items and Stages Item 1 Stage 4 Item 2 Stage 3 Item 3 Stage 2 Item 4 Stage 1 To accompany Quantitative Analysis for Management, 8e by Render/Stair/Hanna M2-11 © 2003 by Prentice Hall, Inc. Upper Saddle River, NJ 07458 Roller Transport Problem Solution Final Solution Stage Optimal Optimal Decision Return 4 6 18 3 0 0 2 0 0 1 2 10 Total 8 28 To accompany Quantitative Analysis for Management, 8e by Render/Stair/Hanna M2-12 © 2003 by Prentice Hall, Inc. Upper Saddle River, NJ 07458 Dynamic Programming Key Equations • sn Input to stage n • dn Decision at stage n • rn Return at stage n • sn-1 Input to stage n-1 • tn Transformation function at stage n • sn-1 = tn [sn dn] General relationship between stages • fn Total return at stage n To accompany Quantitative Analysis for Management, 8e by Render/Stair/Hanna M2-13 © 2003 by Prentice Hall, Inc. Upper Saddle River, NJ 07458