ppsbm (version 0.2.2)

convertNodePair: Convert node pair \((i,j)\)

Description

Convert node pair \((i,j)\) into an index

Directed case :

• The node pair \((i,j)\) with \((i\neq j)\) is converted into the index \((i-1)*(n-1)+j-(i<j)\)

Undirected case :

• The node pair \((i,j)\) with \((i\neq j)\) is converted into the index \((2*n-i)*(i-1)/2 +j-i\)

Usage

convertNodePair(i, j, n, directed)

Value

Index corresponding to the node pair

Arguments

i

Node \(i\) : \(i\in {1, \ldots, n} \)

j

Node \(j\) : \(j\in {1, \ldots, n} \)

n

Total number of nodes : \(i,j\in {1, \ldots, n} \)

directed

Boolean for directed (TRUE) or undirected (FALSE) case

Details

The number of possible node pairs is

• \(N = n*(n-1)\) for the directed case

• \(N = n*(n-1)/2\) for the undirected case

which corresponds to the cardinality of data$type.seq

Examples

# Convert the node pair (3,7) into an index, where the total number of nodes is 10,
# for directed and undirected graph

i <- 3
j <- 7
n <- 10

directedIndex <- convertNodePair(i,j,n,TRUE)
undirectedIndex <- convertNodePair(i,j,n,FALSE)