[R] calculation of inertial difference with huygens theorem in ward clustering ?
nicolas.baurin at univ-orleans.fr
Tue Dec 5 09:32:54 CET 2000
Hello to the R people,
within ward clustering the distance calculated to decide the clustering
of 2 subsets (h1 and h2) is the variation of inertia :
i've been said that a way to calculate faster this d(h1,h2) is using the
huygens theorem decomposing the inertia into "the inertia to the
centroid + the distance to an axe" (that's my version ...). My problem
is that i don't really see how to simplify the d(h1,h2) expression using
the theorem and then go faster?
Thanks in advance,
Laboratoire de Chimiométrie - Modélisation Moléculaire
Institut de Chimie Organique et Analytique, UMR 6005
Université d'Orléans, BP 6759
45067 ORLEANS Cedex 2, France
Tel: (33+) 2 38 49 45 77
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