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Understand bin packing problem, optimal and approximation algorithms, and practical implementations for efficient packing. Learn from professor C. L. Liu's insightful slides on packing algorithms and strategies.
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These slides on 1-D bin packing are adapted from slides from Professor C. L. Liu former President (1998-2002) Tsing Hua University, Hsinchu, Taiwan). Bin Packing (1-D)
.1 .2 .5 .5 .7 .5 .6 .2 .4 Bin Packing (1-D) The bins; (capacity 1) Bin Packing Problem 1 …… .5 .7 .5 .2 .4 .2 .5 .1 .6 Items to be packed
.1 .2 .5 .5 .7 .5 .6 .2 .4 Bin Packing (1-D) Bin Packing Problem 1 …… .5 .7 .5 .2 .4 .2 .5 .1 .6 Optimal Packing N0= 4
.4 .2 .2 .5 .1 .2 .5 .7 .5 .5 .5 .4 .7 .5 .6 .6 .2 Next Fit Packing Algorithm Bin Packing Problem .5 .7 .5 .2 .4 .2 .5 .1 .6 .1 N0= 4 Next Fit Packing Algorithm N= 6
Approximation Algorithms: Not optimal solution, but with some performance guarantee (eg, no worst than twice the optimal) Even though we don’t know what the optimal solution is!!! Bin Packing (1-D)
aj-1 ak-1 ai-1 am-1 … . . . . . . . . . . . . . . . . . . aj ak am a1 ai al Next Fit Packing Algorithm Let a1+ a2 + …….. = 2 N – 1 N0 ≈ a1+……..+ ai > 1 ai+……..+ aj > 1 aj+……..+ ak > 1 al+……..+ am > 1 . . . . .
aj-1 ak-1 ai-1 am-1 … . . . . . . . . . . . . . . . . . . aj ak am a1 ai al Next Fit Packing Algorithm (simpler proof) s(B1)+s(B2)> 1 s(B2)+s(B3)> 1 … … … … … s(BN-1)+s(BN)> 1 Let a1+ a2+ … = 2 > N – 1 2N0 2 N – 1 . . . . . 2( s(B1)+s(B2)+…+ s(BN) ) > N – 1
.4 .2 .2 .1 .1 .2 .2 .7 .7 .5 .5 .5 .5 .5 .5 .4 .6 .6 First Fit PackingAlgorithm .5 .7 .5 .2 .4 .2 .5 .1 .6 Next Fit Packing Algorithm First Fit Packing Algorithm N= 5 (Proof omitted)