Dear R users, I discovered something strange using the function agnes() of the cluster package on R 3.0.1 and on R 2.14.1. Indeed, the clusterings obtained are different whereas I ran exactly the same code. I quickly looked at the source code of the function and I discovered that there was an important change: agnes() in R 2.14.1 used a FORTRAN code whereas agnes() in R 3.0.1 uses a C code. Here is one of the contingency table between R 2.14.1 and R 3.0.1: classe.agnTani.2.14.1 classe.agnTani.3.0.1 1 2 3 1 74 0 229 2 0 235 0 3 120 0 15 So, I was wondering if it was normal that the C and FORTRAN codes give different results? Best regards, Hugo Varet [[alternative HTML version deleted]]
Martin Maechler
2013-Jun-10 13:12 UTC
[R] agnes() in package cluster on R 2.14.1 and R 3.0.1
>>>>> Hugo Varet <varethugo at gmail.com> >>>>> on Sun, 9 Jun 2013 11:43:32 +0200 writes:> Dear R users, > I discovered something strange using the function agnes() of the cluster > package on R 3.0.1 and on R 2.14.1. Indeed, the clusterings obtained are > different whereas I ran exactly the same code. hard to believe... but .. > I quickly looked at the source code of the function and I discovered that > there was an important change: agnes() in R 2.14.1 used a FORTRAN code > whereas agnes() in R 3.0.1 uses a C code. well, it does so quite a bit longer, e.g., also in R 2.15.0 > Here is one of the contingency table between R 2.14.1 and R 3.0.1: > classe.agnTani.2.14.1 > classe.agnTani.3.0.1 1 2 3 > 1 74 0 229 > 2 0 235 0 > 3 120 0 15 > So, I was wondering if it was normal that the C and FORTRAN codes give > different results? It's not normal, and I'm pretty sure I have had many many examples which gave identical results. Can you provide a reproducible example, please? If the example is too large [for dput() ], please send me the *.rda file produced from save(<your data>, file=<the file I neeed>) *and* a the exact call to agnes() for your data. Thank you in advance! Martin Maechler, the one you could have e-mailed directly to using maintainer("cluster") ... > Best regards, > Hugo Varet > [[alternative HTML version deleted]] ^^^^^^^^^^^^^ try to avoid, please ^^^^^^^^^^^^^^^^^ > ______________________________________________ > R-help at 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. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ yes indeed, please.