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CSE 6405Graph Drawing
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Text Books
• T. Nishizeki and M. S. Rahman, Planar Graph Drawing, World Scientific, Singapore, 2004.
• G. Di Battista, P. Eades, R. Tamassia, I. G. Tollies, Graph Drawing: Algorithms for the visualization of Graphs, Prentice-Hall Inc., 1999.
Marks Distribution
• Attendance 10• Participation in Class Discussions 5• Presentation 20• Review Report/Survey Report/
Slide Prepration 10• Examination 55
Presentation
A paper (or a chapter of a book) from the area of Graph Drawing will be assigned to you.You have to read, understand and present the paper. Use PowerPoint slides for presentation.
Presentation Format
Problem definitionResults of the paperContribution of the paper in respect to
previous resultsAlgorithm and methodology including
outline of the proofsFuture works, open problems and your
idea
Presentation Schedule
• Presentation time: 25 minutes
• Presentation will start from 5th week.
Graphs and Graph Drawings
A diagram of a computer network
ATM-SW
ATM-SW
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ATM-SW
ATM-SW
ATM-HUBATM-RT
ATM-RT
ATM-HUB
ATM-HUB
ATM-RT
ATM-RT
ATM-HUB
STATIONSTATION
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STATIONATM-HUB
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Objectives of Graph Drawings
To obtain a nice representation of a graph so that the structure of the graph is easily understandable.
structure of the graph is difficult to understand
structure of the graph is easy to understand
Nice drawing
Symmetric Eades, Hong
The drawing should satisfy some criterion arising from the application point of view.
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not suitable for single layered PCB
suitable for single layered PCB
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Objectives of Graph Drawings
Diagram of an electronic circuit
Wire crossings
Drawing Styles
A drawing of a graph is planar if no two edges intersect in the drawing. It is preferable to find a planar drawing of a graph if the graph has such a drawing. Unfortunately not all graphs admit planar drawings. A graph which admits a planar drawing is called a planar graph.
Planar Drawing
Polyline Drawing
A polyline drawing is a drawing of a graph in which each edge of the graph is represented by a polygonal chain.
Straight Line Drawing
Plane graph
Straight Line Drawing
Plane graphStraight line drawing
Straight Line Drawing
Each vertex is drawn as a point.
Plane graphStraight line drawing
Straight Line Drawing
Each vertex is drawn as a point.
Each edge is drawn as a single straight line segment.
Plane graphStraight line drawing
Straight Line Drawing
Each vertex is drawn as a point.
Each edge is drawn as a single straight line segment.
Plane graphStraight line drawing
Every plane graph has a straight line drawing.
Wagner ’36 Fary ’48Polynomial-time algorithm
Convex drawing
Orthogonal drawing Box-orthogonal Drawing
Rectangular Drawing Box-rectangular Drawing
Octagonal drawing
A 46
B 65
C 11D 56
E
23
F 8
H 37
G 19
I 12 J 14
K 27
Grid Drawing
• When the embedding has to be drawn on a raster device, real vertex coordinates have to be mapped to integer grid points, and there is no guarantee that a correct embedding will be obtained after rounding.
• Many vertices may be concentrated in a small region of the drawing. Thus the embedding may be messy, and line intersections may not be detected.
• One cannot compare area requirement for two or more different drawings using real number arithmetic, since any drawing can be fitted in any small area using magnification.
Grid Drawing
Visibility drawing
A visibility drawing of a plane graph G is a drawing of G where each vertex is drawn as a horizontal line segment and each edge is drawn as a vertical line segment. The vertical line segment representing an edge must connect points on the horizontal line segments representing the end vertices.
A 2-visibility drawing is a generalization of a visibility drawing where vertices are drawn as boxes and edges are drawn as either a horizontal line segment or a vertical line segment
A 2-visibility drawing
Properties of graph drawing
Area. A drawing is useless if it is unreadable. If the used areaof the drawing is large, then we have to use many pages, or we must decrease resolution, so either way the drawing becomes unreadable. Therefore one major objective is to ensure a small area. Small drawing area is also preferable in application domains like VLSI floorplanning.
Aspect Ratio. Aspect ratiois defined as the ratio of the length of the longest side to the length of the shortest side of the smallest rectangle which encloses the drawing.
Bends. At a bend, the polyline drawing of an edge changes direction, and hence a bend on an edge increases the difficulties of following the course of the edge. For this reason, both the total number of bends and the number of bends per edge should be kept small.
Crossings. Every crossing of edges bears the potential of confusion, and therefore the number of crossings should be kept small.
Shape of Faces. If every face has a regular shape in a drawing, the drawing looks nice. For VLSI floorplanning, it is desirable that each face is drawn as a rectangle.
Symmetry. Symmetry is an important aesthetic criteria in graph drawing. A symmetryof a two-dimensional figure is an isometry of the plane that fixes the figure.
Angular Resolution. Angular resolution is measured by the smallest angle between adjacent edges in a drawing. Higher angular resolution is desirable for displaying a drawing on a raster device.
Applications of Graph Drawing
Floorplanning
VLSI Layout
Circuit Schematics
Simulating molecular structures
Data Mining
Etc…..
VLSI Layout
EA
B
C
F
G
D
VLSI FloorplanningVLSI Floorplanning
Interconnection graph
EA
B
C
F
G
D
AB
EC
F
G
D
VLSI FloorplanningVLSI Floorplanning
Interconnection graph VLSI floorplan
EA
B
C
F
G
D
AB
EC
F
G
D
VLSI FloorplanningVLSI Floorplanning
Interconnection graph VLSI floorplan
EA
B
C
F
G
D
AB
EC
F
G
D
VLSI FloorplanningVLSI Floorplanning
Interconnection graph VLSI floorplan
EA
B
C
F
G
D
AB
EC
F
G
D
VLSI FloorplanningVLSI Floorplanning
AB
E
C
F
G
D
Interconnection graph VLSI floorplan
Dual-like graph
EA
B
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D
AB
EC
F
G
D
VLSI FloorplanningVLSI Floorplanning
AB
E
C
F
G
D
AB
E
C
F
G
D
Interconnection graph VLSI floorplan
Dual-like graph Add four corners
EA
B
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F
G
D
AB
EC
F
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VLSI FloorplanningVLSI Floorplanning
AB
E
C
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D
AB
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Interconnection graph VLSI floorplan
Dual-like graph Add four corners
Rectangular drawing
Rectangular Drawings
Plane graph G of 3
Input
Rectangular Drawings
Rectangular drawing of GPlane graph G of 3
Input Output
corner
Rectangular Drawings
Rectangular drawing of GPlane graph G of 3
Each vertex is drawn as a point.Input Output
corner
Rectangular Drawings
Rectangular drawing of GPlane graph G of 3
Each edge is drawn as a horizontal or a vertical line segment.
Each vertex is drawn as a point.Input Output
corner
Rectangular Drawings
Rectangular drawing of GPlane graph G of 3
Each edge is drawn as a horizontal or a vertical line segment.
Each face is drawn as a rectangle.
Each vertex is drawn as a point.Input Output
corner
Not every plane graph has a rectangular drawing.
EA
B
C
F
G
D
AB
EC
F
G
D
VLSI FloorplanningVLSI Floorplanning
Interconnection graph VLSI floorplan
Rectangular drawing
EA
B
C
F
G
D
AB
EC
F
G
D
VLSI FloorplanningVLSI Floorplanning
Interconnection graph VLSI floorplan
Rectangular drawing
Unwanted adjacency
Not desirable for MCM floorplanning andfor some architectural floorplanning.
A
B
E C
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D
MCM FloorplanningMCM Floorplanning SherwaniSherwani
Architectural FloorplanningArchitectural Floorplanning Munemoto, Katoh, ImamuraMunemoto, Katoh, Imamura
EA
B
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F
G
D
Interconnection graph
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B
E C
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MCM FloorplanningMCM FloorplanningArchitectural FloorplanningArchitectural Floorplanning
EA
B
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G
D
Interconnection graph
MCM FloorplanningMCM FloorplanningArchitectural FloorplanningArchitectural Floorplanning
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FG
CD
EA
B
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Interconnection graph
Dual-like graph
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B
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MCM FloorplanningMCM FloorplanningArchitectural FloorplanningArchitectural Floorplanning
A
E
B
FG
CD
EA
B
C
F
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D
Interconnection graph
Dual-like graph
A
B
E C
F
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D
MCM FloorplanningMCM FloorplanningArchitectural FloorplanningArchitectural Floorplanning
A
E
B
FG
CD
EA
B
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F
G
D
A
E
B
FG
CD
Interconnection graph
Dual-like graph
A
B
E C
F
G
D
MCM FloorplanningMCM FloorplanningArchitectural FloorplanningArchitectural Floorplanning
A
E
B
FG
CD
EA
B
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F
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D
A
E
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FG
CD
Box-Rectangular drawing
Interconnection graph
Dual-like graph
A
B
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D
dead space
Applications
Entity-relationship diagramsFlow diagrams
Applications
Circuit schematics
Minimization of bends reduces the number of “vias” or “throughholes,” and hence reduces VLSI fabrication costs.
A planar graph
planar graph non-planar graph
Planar graphs and plane graphs
An embedding is not fixed.A planar graph may have an exponential number of embeddings.
A plane graph is a planar graph with a fixed embedding.
different plane graphs
same planar graph
・・・・
Graph Drawing Data Mining
Internet Computing
Social Sciences
Software Engineering
Information Systems
Homeland Security
Web Searching