[R] (no subject)

From: Jan de Leeuw <deleeuw_at_stat.ucla.edu>
Date: Sat 06 Aug 2005 - 09:51:56 EST

This does metric/nonmetric weighted least squares multidimensional scaling
using the smacof algorithm (deleeuw, 1977, in barra et al (eds), recent developments
in statistics; or deleeuw and heiser, 1980, in krishnaiah (ed), multivariate
analysis V). Uses a dist object for both dissimilarities and weights, which should both be non-negative for convergence. Fits euclidean distances only.

Monotone regression is done by pool-adjacent-violators, implemented in pava.R. The pava function can actually do monotone regression using weighted means, medians, or p-fractiles -- although for mds only means are used.

Somebody asked for this and it may be useful to others. It is not written
for efficiency, but the flexibility of allowing weights can be handy. By using relaxed smacof updates (see deleeuw and heiser or the book by borg and groenen) we can make this about twice as fast -- but that will come later. Feel free to tinker away.

Jan de Leeuw; Distinguished Professor and Chair, UCLA Department of Statistics;
Editor: Journal of Multivariate Analysis, Journal of Statistical Software
US mail: 8130 Math Sciences Bldg, Box 951554, Los Angeles, CA 90095-1554 phone (310)-825-9550; fax (310)-206-5658; email: deleeuw@stat.ucla.edu .mac: jdeleeuw ++++++ aim: deleeuwjan ++++++ skype: j_deleeuw homepages: http://gifi.stat.ucla.edu ++++++ http://www.cuddyvalley.org    

           No matter where you go, there you are. --- Buckaroo Banzai



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