The mailing list ate the attachments, so here they are again.

R code
https://gist.github.com/4270628

Log
http://pastebin.com/0e49CTsL



Andrew

-----Original Message-----
From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On 
Behalf Of Andrew Ziem 
Sent: Wednesday, December 12, 2012 10:33 AM
To: r-help@r-project.org
Subject: [R] extracting splitting rules from GBM

I am extracting splitting rules from Greg Ridgeway's GBM 1.6-3.2 in R 2.15.2, 
so I can run classification in a production system outside of R.  I have it 
working and verified for a dummy data set with all variable types (numeric, 
factor, ordered) and missing values, but in the titanic survivors data set the 
splitting rule for factors does not make sense.  The attached code and log 
below explains the dilemma.

Also I tried tracing the predictions backwards (also in the log and code), but 
it doesn't make sense. The first record is a female and predict.gbm() gives 
values (around 0.0108) that land her on rule 7 on both trees.  Then 7's parent 
is 5, and 5's parent is 0, but in each tree rule 0 has a different 
SplitCodePred.


Andrew

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