Gabriel

Thanks for your feedback. Indeed, I was not particularly clear here. The empty model is just a very special case in a more general setting. I'd have to work around this deficiency in my code -- sure I can do that, but I thought a generic solution should be possible. In particular, I'm using predict.rpart(..., type = "prob") -- this just reflects the observed relative frequencies.


Cheers

Kirill


On 08/15/2014 06:44 PM, Gabriel Becker wrote:
Kirill,

Perhaps I'm just being obtuse, but what are you proposing rpart do in the case of an empty model? Return a "tree" that always guesses the most common label, or doesn't guess at all (NA)? It doesn't seem like you'd need rpart for either of those.

~G


On Wed, Aug 13, 2014 at 3:51 AM, Kirill Müller <kirill.muel...@ivt.baug.ethz.ch <mailto:kirill.muel...@ivt.baug.ethz.ch>> wrote:

    Dear list


    For my work, it would be helpful if rpart worked seamlessly with
    an empty model:

    library(rpart); rpart(formula=y~0, data=data.frame(y=factor(1:10)))

    Currently, an unrelated error (originating from na.rpart) is thrown.

    At some point in the near future, I'd like to release a package to
    CRAN which uses rpart and relies on that functionality. I have
    prepared a patch (minor modifications at three places, and a test)
    which I'd like to propose for inclusion in the next CRAN release
    of rpart. The patch can be reviewed at
    https://github.com/krlmlr/rpart/tree/empty-model, the files (based
    on the current CRAN release 4.1-8) can be downloaded from
    https://github.com/krlmlr/rpart/archive/empty-model.zip.

    Thanks for your attention.


    With kindest regards

    Kirill Müller

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--
Gabriel Becker
Graduate Student
Statistics Department
University of California, Davis

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