HierClust <- function(arr, wts)
{

# FM, Jan. 2004   Update DZ, Mar. 2006

# Example of use.
# dyn.load("C:/TEMP/hierclust.dll") 
# arr <- matrix(c(1,4,2,3,0,2,1,2,4,2,3,2),nrow=4,ncol=3)
# wts <- as.double(c(0.7, 0.3, 0.5, 0.8))

# NOTE: By careful with input data.  read.table produces an object of 
# type list.  Convert this to a matrix (e.g. y <- as.matrix(x) ).

order <- as.integer(rep(0,nrow(arr)))
ia <- as.integer(rep(0,nrow(arr)-1))
ib <- as.integer(rep(0,nrow(arr)-1))
height <- as.double(rep(0,nrow(arr)-1))

data <- as.double(rep(0,nrow(arr)))

count <- 1
for (row in 1:nrow(arr)) {
  for (col in 1:ncol(arr)) {
    data[count] <- arr[row, col]
    count <- count + 1
  }
}


output <-  .C("HierClust", order,
                          ia,
                          ib,
                          height,
                          data,
                          wts,
                          nrow(arr),
                          ncol(arr))


retlist <- list(merge=cbind(output[[2]], output[[3]]),
                height=output[[4]],order=output[[1]])

retlist 

}