lec18-steiner

E costt32costtopt steiner tree heuristics observation

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: proximation can be easily improved cost(T)=6 cost(T)=4 Difficulty: where to add Steiner points?? L-Shaped MST approach Ho, Vijayan and Wong, “ A new approach to the rectilinear steiner tree problem”, DAC’89, pp161-166 Basic Idea: Each on-degenerated edge in MST has two possible L-shaped layouts, choose one for each edge in MST to maximize overlap. degenerate edges MST non-degenerate edge two L-shaped layouts one L-shaped mapping Problem: Compute the best L-shaped mapping another L-shaped mapping Key Ideas in L-RST Approach Separable MST: bounding boxes of every two nonadjacent edges don’t intersect or overlap non-separable MST separable MST Theorem: Every point set has a separable MST Theorem: Each node is adjacent to at most 8 edges (6 non-degenerate edges) in a rectilinear MST Theorem: We can compute an optimal L-shaped implementation of an MST in O(2d•n) time. ( Dynamic Programming Approach). Note that d≤6 Compute a Separabl...
View Full Document

Ask a homework question - tutors are online