文档介绍：Practical work analysis
(with R and igraph)
G´abor Cs´ardi
******@
Department of Biophysics, KFKI Research Institute for Nuclear and Particle Physics of the
Hungarian Academy of Sciences, Budapest, Hungary
Currently at
Department of Medical ics,
University of Lausanne, Lausanne, Switzerland
What is work (or graph)?
Practical work analysis – WU Wien 2
What is work (or graph)?
Practical work analysis – WU Wien 3
What is work (or graph)?
Practical work analysis – WU Wien 4
What is a graph?
• Binary relation (=edges) between elements of a set (=vertices).
What is a graph?
• Binary relation (=edges) between elements of a set (=vertices).
• .
vertices = {A, B, C, D, E}
edges = ({A, B}, {A, C}, {B, C}, {C, E}).
What is a graph?
• Binary relation (=edges) between elements of a set (=vertices).
• .
vertices = {A, B, C, D, E}
edges = ({A, B}, {A, C}, {B, C}, {C, E}).
• It is“better”to draw it:
E
D
C
B
A
What is a graph?
• Binary relation (=edges) between elements of a set (=vertices).
• .
vertices = {A, B, C, D, E}
edges = ({A, B}, {A, C}, {B, C}, {C, E}).
• It is“better”to draw it:
E B
D
A
C
C
E
B
A D
Practical work analysis – WU Wien 5
Undirected and directed graphs
• If the pairs are unordered, then the graph is undirected:
B
A C
vertices = {A, B, C, D, E} E
edges = ({A, B}, {A, C}, {B, C}, {C, E}). D
Undirected and directed graphs
• If the pairs are unordered, then the graph is undirected:
B
A C
vertices = {A, B, C, D, E} E
edges = ({A, B}, {A, C}, {B, C}, {C, E}). D
• Otherwise it is directed:
B
A C
vertices = {A, B, C, D, E} E
edges = ((A, B), (A, C), (B, C), (C, E)). D
Practical work analysis – WU Wien 6