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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
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
It gives 3/2-approximation, i.e. cost(T)≤3/2cost(Topt) Steiner Tree Heuristics
Observation: MST ap...
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