[R--gR] deal: heuristic search lowers the score?

[Claus Dethlefsen / Aalborg Sygehus]

Dear Sam
 
The score should not be positive, so something is not right here. This is possibly caused by numerical instabilities, either because the jointprior has a too low size of the imaginary database, or because the continuous variables need to be rescaled. If, for example, you have a continuous variable taking values around 0.001, try multiplying the variable by 1000.
 
I have not explored this further, so I have not got a really good explanation for what is going on.
 
The relscore in a networklist (e.g. after you have sorted the networks according to their score using 'nwfsort') is the relative score of the networks using the network with the highest score as reference. (see help(nwfsort)).
 
Best,
Claus
 
________________________________
Claus Dethlefsen, Msc, PhD
Statistiker ved Kardiovaskulært Forskningscenter

 
Forskningens Hus
Aalborg Sygehus 
Sdr. Skovvej 15
9000 Aalborg

Tlf:   9932 6863
email: aas.claus.dethlefsen at nja.dk <mailto:aas.claus.dethlefsen at nja.dk> 

________________________________

Fra: r-sig-gr-bounces at stat.math.ethz.ch på vegne af Sam Steingold
Sendt: on 22-03-2006 20:08
Til: dealsoftware at yahoogroups.com
Cc: r-sig-gr at stat.math.ethz.ch
Emne: [R--gR] deal: heuristic search lowers the score?



Hi,
I noticed that the network created by heuristic() has lower score than
the one created by autosearch():

prior <- jointprior(net,nrow(df)*10)
search <- autosearch(net,df,prior,timetrace=TRUE,removecycles=TRUE)
heuristic <- heuristic(getnetwork(search),df,trylist=gettrylist(search))
score(getnetwork(search))
[1] 378.5992
score(getnetwork(heuristic))
[1] 357.014
why?  does this mean that the score is actually the _negative_ of log
likelihood?

also, it is not clear what the relscore is.


PS. I read the paper and the manual...

--
Sam Steingold (http://www.podval.org/~sds) on Fedora Core release 4 (Stentz)
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