CODEWITHSUNDEEP
rmatrixconnectivity
jsts
jsts

Reputation: 259

Create a connectivity matrix in R counting shared membership

Suppose I have a dataset in R indicating the membership of countries in International Organizations (the original dataset can be found here: IGO_stateunit_v2.3.zip).

Here is an example for the basic structure of the data:

cntr <- c('A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J')
UNO <- c(0, 1, 1, 1, 1, 1, 1, 1, 1, 1)
APEC <- c(0, 0, 0, 0, 1, 1, 1, 0, 0, 0)
ASEAN <- c(0, 0, 0, 0, 1, 1, 0, 0, 0, 0)
data <- data.frame(cntr, UNO, APEC, ASEAN)

So the data looks like this, where 1=membership in an organization:

cntr UNO APEC ASEAN
A   0    0     0
B   1    0     0
C   1    0     0
D   1    0     0
E   1    1     1
F   1    1     1
G   1    1     0
H   1    0     0
I   1    0     0
J   1    0     0

What I would like to create with this data in R is a matrix that counts the number of memberships two countries share together. The result should look like this:

cntr A B C D E F G H I J
   A 0 0 0 0 0 0 0 0 0 0
   B 0 0 1 1 1 1 1 1 1 1
   C 0 1 0 1 1 1 1 1 1 1
   D 0 1 1 0 1 1 1 1 1 1
   E 0 1 1 1 0 3 2 1 1 1
   F 0 1 1 1 3 0 2 1 1 1
   G 0 1 1 1 2 2 0 1 1 1
   H 0 1 1 1 1 1 1 0 1 1
   I 0 1 1 1 1 1 1 1 0 1
   J 0 1 1 1 1 1 1 1 1 0

Has anyone an idea how to calculate the connectivity matrix? Help would be greatly appreciated!

Upvotes: 3

Views: 209

Answers (1)

Marat Talipov
Marat Talipov

Reputation: 13314

Your data:

d <- structure(list(cntr = structure(1:10, .Label = c("A", "B", "C", 
"D", "E", "F", "G", "H", "I", "J"), class = "factor"), UNO = c(0L, 
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L), APEC = c(0L, 0L, 0L, 0L, 
1L, 1L, 1L, 0L, 0L, 0L), ASEAN = c(0L, 0L, 0L, 0L, 1L, 1L, 0L, 
0L, 0L, 0L)), .Names = c("cntr", "UNO", "APEC", "ASEAN"), class = "data.frame", row.names = c(NA, 
-10L))

Solution:

  m <- as.matrix(d[,-1])
  m2 <- m %*% t(m)
  # Alternatively, m2 <- tcrossprod(m) can be used with the same result (thanks to @akrun for pointing that out)!
  diag(m2) <- 0
  dimnames(m2) <- list(LETTERS[1:10],LETTERS[1:10])
  m2
  #   A B C D E F G H I J
  # A 0 0 0 0 0 0 0 0 0 0
  # B 0 0 1 1 1 1 1 1 1 1
  # C 0 1 0 1 1 1 1 1 1 1
  # D 0 1 1 0 1 1 1 1 1 1
  # E 0 1 1 1 0 3 2 1 1 1
  # F 0 1 1 1 3 0 2 1 1 1
  # G 0 1 1 1 2 2 0 1 1 1
  # H 0 1 1 1 1 1 1 0 1 1
  # I 0 1 1 1 1 1 1 1 0 1
  # J 0 1 1 1 1 1 1 1 1 0

EDIT: slightly more compact solution:

  rownames(d) <- d$cntr
  m <- tcrossprod(as.matrix(d[,-1]))
  diag(m) <- 0
  m

Upvotes: 6

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