[R] agnes() in package cluster on R 2.14.1 and R 3.0.1

Martin Maechler maechler at stat.math.ethz.ch
Mon Jun 10 15:12:39 CEST 2013

>>>>> 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 ^^^^^^^^^^^^^^^^^

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yes indeed, please.

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