tag:blogger.com,1999:blog-7407486920844354583.post5592739723875580600..comments2023-12-20T07:40:56.484+00:00Comments on Raptor's Nest: Principal coordinate analysis and the quest for a solution to a non-existent problemRaptor's Nesthttp://www.blogger.com/profile/01451618880276065935noreply@blogger.comBlogger5125tag:blogger.com,1999:blog-7407486920844354583.post-74601411758584280052013-01-11T13:08:40.292+00:002013-01-11T13:08:40.292+00:00I'm also having a problem very close to this o...I'm also having a problem very close to this one, with the exception that i'm actually getting a non-euclidean distance matrix out of UniFrac (strictly speaking, NOT a positive semi-definite matrix). And i'm also wondering what the hell to do with those negative eigenvalues. Does anyone know what they ultimately mean? Paulyhttps://www.blogger.com/profile/17006776999223065956noreply@blogger.comtag:blogger.com,1999:blog-7407486920844354583.post-45063694843081554182011-01-31T00:22:57.537+00:002011-01-31T00:22:57.537+00:00Holy crap! I found this blog post with the EXACT ...Holy crap! I found this blog post with the EXACT same problem in R. You just saved me some time.Unknownhttps://www.blogger.com/profile/15005759516287557095noreply@blogger.comtag:blogger.com,1999:blog-7407486920844354583.post-42277992282742156122010-04-07T09:07:54.347+01:002010-04-07T09:07:54.347+01:00Hi Sudharsan,
I've found it difficult to find...Hi Sudharsan,<br /><br />I've found it difficult to find a single good reference on principal coordinates and principal components analyses, so I had to read multiple sources, namely multivariate statistics text books. But there is a pretty good essay by Norman MacLeod (Natural History Museum, London) that explains in relatively simple terms PCA and other related methods: <br /><br />http://www.palass.org/modules.php?name=palaeo_math&page=3<br /><br />The great thing about this essay series is that it starts with correlations and regressions and extends the line of thought to PCA.Raptor's Nest (old)https://www.blogger.com/profile/11093451947295359924noreply@blogger.comtag:blogger.com,1999:blog-7407486920844354583.post-92191054899416207272010-04-07T05:15:43.694+01:002010-04-07T05:15:43.694+01:00I'm newbie for principal coordinate analysis. ...I'm newbie for principal coordinate analysis. Infact my current assign ment ot o write about principal coordinate analysis and principal component analysis.... but the problem is that i dun get enough simple reference to get an idea about these principals....can u please any useful explanation? thank you.Sudharsan Selvarajahttps://www.blogger.com/profile/02412931118104055289noreply@blogger.comtag:blogger.com,1999:blog-7407486920844354583.post-77980185368492987102009-05-13T17:59:00.000+01:002009-05-13T17:59:00.000+01:00I never make these sort of mistaks
es...I never make these sort of mistaks<br />es...Malacodahttps://www.blogger.com/profile/02602635447222532525noreply@blogger.com