[R] My own correlation structure with nlme

[Mohand]

Dear all,

I am trying to define my own corStruct which is different from the 
classical one available in nlme. The structure of this correlation is 
given below.
I am wondering to know how to continue with this structure by using 
specific functions (corMatrix, getCovariate, Initialize,...) in order to 
get a structure like corAR1, corSymm which will be working for my data.

Thanks  in advance.

Regards

M. Feddag




*Correlation structure _
_*


pairCorr <- function(A, B, lowerTriangle = TRUE){
  n <- length(A)
  m <- length(B)
  if (n != m) stop("A and B must have same length")
  result <- matrix(0, n, n)
  same.A <- outer(A, A, "==")
  same.B <- outer(B, B, "==")
  A.matches.B <- outer(A, B, "==")
  B.matches.A <- outer(B, A, "==")
  result <- result + 0.5*same.A + 0.5*same.B -
                     0.5*A.matches.B - 0.5*B.matches.A
  rownames(result) <- colnames(result) <- paste(A, B, sep = "")
  if (lowerTriangle) result <- result[row(result) > col(result)]
  result
}