[R] Error in mvpart example

Wearn, Oliver
Fri, 26 Feb 2010 13:55:29 -0000

Dear all,

I'm getting an error in one of the stock examples in the 'mvpart'
package. I tried:

require(mvpart)
data(spider)
fit3 <-
rpart(gdist(spider[,1:12],meth="bray",full=TRUE,sq=TRUE)~water+twigs+reft+herbs+moss+sand,spider,method="dist")
#directly from ?rpart
summary(fit3)

...which returned the following:

Error in apply(formatg(yval, digits - 3), 1, paste, collapse = ",",
sep = "") :
  dim(X) must have a positive length

This seems to be a problem with the cross-validation, since the
"xerror" and "xstd" columns are missing from the summary
table as well.

Using the mpart() wrapper results in the same error:

fit4<-mvpart(gdist(spider[,1:12],meth="bray",full=TRUE,sq=TRUE)~water+twigs+reft+herbs+moss+sand,spider,method="dist")
summary(fit4)

Note, changing the 'method' argument to ="mrt" seems,
superficially, to solve the problem. However, when the dependent variable is a
dissimilarity matrix, shouldn't method="dist" be used (as per the
examples)?

Thanks, in advance, for any help on this error.

Oliver