convertNodePair {ppsbm}

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)

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

Value

Index corresponding to the node pair

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)