Thank you! I just wanted to know how one goes from the values returned by kmeans to a distance metric. You have shown me that is simply the squared distance from the centers! Thanks again. John
John David Sorkin M.D., Ph.D. Chief, Biostatistics and Informatics University of Maryland School of Medicine Division of Gerontology Baltimore VA Medical Center 10 North Greene Street GRECC (BT/18/GR) Baltimore, MD 21201-1524 (Phone) 410-605-7119 (Fax) 410-605-7913 (Please call phone number above prior to faxing)>>> Ranjan Maitra <maitra.mbox.igno...@inbox.com> 10/2/2012 2:52 PM >>> On Tue, 2 Oct 2012 14:32:12 -0400 John Sorkin <jsor...@grecc.umaryland.edu> wrote: > Ranjan, > Thank you for your help. What eludes me is how one computes the distance from > each cluster for each subject. For my first subject, datascaled[1,], I have > tried to use the following: > v1 <- sum(fit$centers[1,]*datascaled[1,]) > v2 <- sum(fit$centers[2,]*datascaled[1,]) > v3 <- sum(fit$centers[2,]*datascaled[1,]) > hoping the max(v1,v2,v3) would reproduce the group assignment, i.e. simply > assign the subject to the group that gives the largest value, but it does > not. How is the distance to the three clusters computed for each subject? > Thanks, > John Well, it should be: v <- vector(length = 3) for (i in 1:3) v[i] <- sum((fit$centers[i, ] - datascaled[1, ])^2) whichmin(v) should provide the cluster assignment. Btw, there is a better, more efficient and automated way to do this, i.e. avoid the loop using matrices and arrays and apply, but I have not bothered with that here. Ranjan -- Important Notice: This mailbox is ignored: e-mails are set to be deleted on receipt. For those needing to send personal or professional e-mail, please use appropriate addresses. ____________________________________________________________ GET FREE SMILEYS FOR YOUR IM & EMAIL - Learn more at http://www.inbox.com/smileys Works with AIM?, MSN? Messenger, Yahoo!? Messenger, ICQ?, Google Talk? and most webmails Confidentiality Statement: This email message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original message.
______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
