Cleanup of main. Adding Katz

Schrick-Noah_CG-Analysis.R

@@ -4,14 +4,8 @@
 # Noah L. Schrick - 1492657
 
 library(igraph)
-library(sna)
-library(Rgraphviz) # Reading graphviz' "dot" files
-library(readr)
 
-################# Read in the previously generated networks #################
-# If sourcing:
-#setwd(getSrcDirectory()[1])
-# If running:
+################## Read in the previously generated networks ##################
 setwd(dirname(rstudioapi::getActiveDocumentContext()$path))
 source("./CG_Files/manual_import.R")
 
@@ -19,6 +13,11 @@ car <- import_networks(1)
 hipaa <- import_networks(2)
 pci <- import_networks(3)
 
-car.deg <- degree(car)
-hipaa.deg <- degree(hipaa)
-pci.deg <- degree(pci)
+################################ Centralities ################################
+source("centralities.R")
+
+#### Katz
+car.katz <- katz.cent(car)
+hipaa.katz <- katz.cent(hipaa)
+pci.katz <- katz.cent(pci)
+

centralities.R

@@ -0,0 +1,21 @@
+katz.cent <- function(A, alpha=NULL, beta=NULL){ #NULL sets the default value
+  if (class(A) == 'igraph'){
+    #Error checking. Turn into adj matrix.
+    A <- get.adjacency(A)
+  }
+  
+  lam.dom <- eigen(A)$values[1] #dom eigenvec
+  if (is.null(alpha)){
+    alpha <- 0.9 * (1/lam.dom) #Set alpha to 90% of max allowed
+  }
+  
+  n <- nrow(A)
+  if (is.null(beta)){
+    beta <- matrix(rep(1/n, n),ncol=1)
+  }
+  
+  #Katz scores
+  scores <- solve(diag(n) - alpha*A,beta)
+  
+  return(scores)
+}