[R] 1-SE rule in mvpart

AlexisMarceau amarceau at bcgn.grignon.inra.fr
Tue Sep 16 11:17:36 CEST 2008


Hello,

I'm using mvpart option xv="1se" to compute a regression tree of good size
with the 1-SE rule.
To better understand 1-SE rule, I took a look on its coding in mvpart, which
is :

Let z be a rpart object ,
xerror <- z$cptable[, 4]
xstd <- z$cptable[, 5]
splt <- min(seq(along = xerror)[xerror <= min(xerror) + xvse * xstd])

I interprete this as following: the simplest tree with xerror under
min(xerror) + its own xstd

Neverthless, in some article I read the following rule:

the simplest tree with xerror under min(xerror) + xstd corresponding to the
min(xerror)

Is this a mistake or any variant of 1-SE rule ? 

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