cut dendrogram into clusters/groups and save to files

[emanlee]

Here is a figure on this home page: https://github.com/lbehnke/hierarchical-clustering-java. From this dendrogram, how can we get clusters or groups. For example, if we want get two clusters, it should be [o6] [o1 o2 o3 o4 o5]; If we want get three clusters, it should be [06] [03 05] [01 02 04 ]. How to use codes to get such clusters and output them to console or files? Thanks!

In my case, I have more than 800 samples/genes. After clustering, the dendrogram is very big and complex, therfore, we need to divide/cut/sect the dendrogram into clusters and save them to files (each file contains the gene names and represents a cluster/group).