rpart trees.row.names of frame contain the (unique) node numbers that
follow a binary ordering indexed by node depth.
Columns of frame include
var, a factor giving the name of the variable used in the split
at each node (leaf nodes are denoted by the string n, the size of each node,
wt, the sum of case weights for the node,
dev, the deviance of each node,
yval, the fitted value of the response at each node,
and splits, a two column matrix of left and right split labels
for each node. Extra response information is in yval2, which contains the number
of events at the node (poisson), or a matrix containing the fitted
class, the class counts for each node and the class probabilities
(classification). Also included in the frame are complexity, the
complexity parameter at which this split will collapse, ncompete,
the number of competitor splits retained, and nsurrogate, the
number of surrogate splits retained.
frame corresponding to
the leaf node that each observation falls into.count, the number of
observations sent left or right by the split (for competitor splits
this is the number that would have been sent left or right had this
split been used, for surrogate splits it is the number missing the
primary split variable which were decided using this surrogate),
ncat, the number of categories or levels for the variable
(+/-1 for a continuous variable), improve, which is the
improvement in deviance given by this split, or, for surrogates, the
concordance of the surrogate with the primary, and index, the
numeric split point. The last column adj gives the adjusted
concordance for surrogate splits. For a factor, the index
column contains the row number of the csplit matrix. For a continuous
variable, the sign of ncat determines whether the subset
x < cutpoint or x > cutpoint is sent to the left.
For rows with zero count the rest of the row should be ignored
as no split was computed.index column
of the splits matrix. The columns record 1 if that
level of the factor goes to the left, 3 if it goes to the
right, and 2 if that level is not present at this node
of the tree (or not defined for the factor).summary.rpart these are rescaled to add to 100.expression and class "term" summarizing
the formula.
Used by various methods, but typically not of direct relevance to users.update(tree).
Optional components include the matrix of predictors (x) and the
response variable (y) used to construct the rpart object.rpart
object. Of these, only the where component has the same length
as the data used to fit the rpart object.
The internal structures were changed in rpart.