[R] Random Forest - Strata

[Coll]

Hi all,

Had struggled in getting "Strata" in randomForest to work on this. 

Can I get randomForest for each of its TREE, to get ALL sample from some
strata to build tree, while leaving some strata TOTALLY untouched as oob?

e.g. in below, how I can tell RF to, 
- for tree 1 in the forest, to use only Site A and B to build the tree,
while using the WHOLE Site C data for the oob error rate,
- for tree 2, use only site A and C to build tree, while using whole site B
data for oob
- for tree 3, use Site B and C, A as oob...?

My command does not work as it would use some sample in all of the sites:
rforest.obj <- randomForest(Presence.f ~., data=dataset.subset, strata =
site.factor)

while 
the setting the corresponding "sampsize" argument seems would only screen
out the Site in all tree building...

Site	Presence	  Length	  Sulphur
A	        Yes	       3.50	        19.42
A	        No	        3.90	        51.09
A	        No	        3.60	        26.75
B	        Yes	       2.60	        9.71
B	        No	        2.20	        9.77
B	        No	        2.60	        8.60
B	        No	        3.00	        35.59
C	        Yes	       3.50	        16.07
C	        No	        3.40	        49.96
C	        No	        3.10	        35.35

Any idea / comments are welcomed.

Thanks in advance.

Coll
-- 
View this message in context: http://r.789695.n4.nabble.com/Random-Forest-Strata-tp2295731p2295731.html
Sent from the R help mailing list archive at Nabble.com.