add more methods for kmeans
add more methods for kmeans

cmu-db/cmdbac,cmu-db/db-webcrawler,cmu-db/db-webcrawler,cmu-db/db-webcrawler,cmu-db/cmdbac,cmu-db/cmdbac,cmu-db/db-webcrawler,cmu-db/cmdbac,cmu-db/cmdbac,cmu-db/db-webcrawler