lec18-steiner

# 14 cjsherwani 92 data structures and basic algorithms

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

This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: erent Steiner trees constructed from a MST (a) (b) (c) (d) Hwang's Thm (76'): The ratio of the cost of a rectilinear MST to that of an optimal RST is no greater than 3/2. (e) Algorithms for VLSI Physical Design Automation 3.15 cjSherwani 92 Rectilinear Steiner Trees Given a set of points on the plane Determine a Steiner tree using only horizontal and vertical v1=(x1,y1) wires( lines) Manhattan distance: cost(v1,v2) =|x1-x2|+|y1-y2| v1=(x1,y1), v2=(x2,y2) v2=(x2,y2) Steiner points Draw a horizontal and a vertical line through each point. Need to consider only grid points as steiner points Prim-based algorithm: Grow a connected subtree by iteratively adding the closest points It gives 3/2-approximation, i.e. cost(T)≤3/2cost(Topt) Steiner Tree Heuristics Observation: MST ap...
View Full Document

{[ snackBarMessage ]}

Ask a homework question - tutors are online