Earth (MARS) package with categorical predictors

Steve, thanks for your reply. Here is what I get.

pkg is a 4-level categorical vector.

is.factor(pkg)

[1] TRUE>

summary(pkg)

BGA PGA QCC QFP 
225  36  19 178

dat <- earth(lifetime ~ pkg+pins+volts+temp+doi+logspd, degree=3) ## The

other vars are continuous.

s <- 243
pr <- c(pkg[s],pins[s],volts[s],temp[s],doi[s],logspd[s])
pkg[s]

[1] BGA
Levels: BGA PGA QCC QFP

pr

[1]    1.000000  256.000000    3.300000  125.000000 2002.258105    4.890349

pred <- predict(dat, newdata=pr)

Error : variable 'pkg' was fitted with type "factor" but type "numeric" was
supplied
Forging on regardless, first few rows of x are
  pkg pins volts temp      doi   logspd
1   1  256   3.3  125 2002.258 4.890349
Error: get.earth.x from model.matrix.earth from predict.earth: the number 6
of columns of x
(after factor expansion) does not match the number 8 of columns of the earth
object
    expanded x:  pkg pins volts temp doi logspd
    object$dirs: pkgPGA pkgQCC pkgQFP pins volts temp doi logspd
Possible remedy: check factors in the input data

Pkg is being passed as numeric 1. I'm unsure how to correctly specify pkg
for predict. In the example you gave, does the data include a categorical?

Chris

-----Original Message-----
From: Stephen Milborrow [mailto:milbo at sonic.net] 
Sent: Monday, November 11, 2013 7:21 AM
To: kinsham at verizon.net
Subject: [R] Earth (MARS) package with categorical predictors

See if you can provide a simple reproducible example.  It's not clear 
exactly what the issue is from your question.  The following simple example 
gives the correct response:

data(etitanic)
a <- earth(survived~., data=etitanic)
predict(a, newdata=etitanic[1,])

Regards,
Steve

Message: 42
Date: Thu, 07 Nov 2013 23:16:18 -0500
From: Chris Wilkinson <kinsham at verizon.net>
To: r-help at r-project.org, Chris Wilkinson <kinsham at verizon.net>
Subject: [R] Earth (MARS) package with categorical predictors
Message-ID: <ml99syxejec3ep0u4h0je78h.1383884178002 at email.android.com>
Content-Type: text/plain; charset=utf-8

It appears to be legitimate to include multi-level categorical and
continuous variables in defining the model for earth (e.g. y ~ cat +
cont1 + cont2) but is it also then possible use categoricals in the
predict method using the earth result? I tried but it returns an error
which is not very informative.

Thanks

Chris