for (i in...)

On 09/12/2007 3:04 PM, Rina Oldager Miehs wrote:

 Hey

 do anyone know why this error occurs??

 >> for(i in 1:n_trait){

 +    for( j in 1:n_trait){
 +    rG[i,j] <- (G_o[i,j]/(sqrt(G_o[i,i]%*%G_o[j,j]))
 +    rP[i,j] <- (P_o[i,j]/(sqrt(P_o[i,i]%*%P_o[j,j]))
 Error: unexpected symbol in:
 > "   rG[i,j] <- (G_o[i,j]/(sqrt(G_o[i,i]%*%G_o[j,j]))
    rP"

Your parentheses don't match on the rG line.  You have 3 lefts and 2 rights.

Duncan Murdoch

Rina,
   Alternatively, you could avoid the entire double loop by using 
matrix operations.  I show this and then reproduce it using the first 
section of your code:

#how to use matrices to avoid looping
n_trait <- 5
X <- matrix( rnorm(100*n_trait),ncol= n_trait) #create a data matrix
G_o <- t(X) %*% X   #create the G_o matrix as a  matrix of cross products
G_o          #show the cross products

dG <- diag(1/sqrt(diag(G_o)))  #divide by the sqrt of the diagonal
rG <- dG %*% G_o %*% dG
rG                              #show the result
#######################
  #abbreviated Rina code using loops
  for(i in 1:n_trait){
     for( j in 1:n_trait){
  rG[i,j] <- G_o[i,j]/(sqrt(G_o[i,i]%*%G_o[j,j])) }}
rG         #compare to above



Bill

William Revelle		http://personality-project.org/revelle.html
Professor			http://personality-project.org/personality.html
Department of Psychology             http://www.wcas.northwestern.edu/psych/
Northwestern University	http://www.northwestern.edu/
Use R for statistics:                          http://personality-project.org/r