Hi

I am using R for a simple hierarchical clustering method for finding protein sequence similarities. I already have a distance matrix computed. I am using hclust method to run it. (Thus I dont want to use dist method). Could anyone tell me what format does my distance matrix need to be for hclust to run?

I used the read.xls method to read my excel file. I need only the lower triangular portion of the matrix. And this I am sending to hclust to be clustered.

d= as.matrix(mat)
hc =hclust(d, method="single")

How ever this is the error i get:

Error in if (n < 2) stop("must have n >= 2 objects to cluster") :    

argument is of length zero

Am I doing this right?

Could anyone please help me out?

Thanks