From: Clément Viel <Clement.Viel_at_polytech-lille.net>

Date: Wed 05 Jul 2006 - 01:11:30 EST

Date: Wed 05 Jul 2006 - 01:11:30 EST

I am currently working on mixtures of two densities ( f(xi,teta)=
(1-teta)*f1(xi) + teta*f2(xi) ),

particularly on the behavior of the variance for teta=0 (so sample only
comes from the first distribution).

To determine the maximum likelihood estimator I use the Newton-Rapdon
Iteration. But when

computing the first derivative I get a none linear function (with several
asymptotes) which is completely

absurd.

This is my function to compute the first derivative:

phy=function(teta,vect1,vect2){

return( sum(( vect2 - vect1) / (( 1 - teta) * vect1 + teta * vect2))) }

Have you got any suggestions, please?

-- Clément Viel Student in engineering school of Polytech-Lille http://www.polytech-lille.fr [[alternative HTML version deleted]]Received on Wed Jul 05 01:25:57 2006______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html

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