[R] Problem with rpart

[Uwe Ligges]

Andrew Zachary wrote:

>  
> Here is an example (though the data are too large to send ). The dataset
> is (6530 x 15). Predictors are continuous N(0,1). Trying to build a
> regression tree.
> 
>  fit <- rpart( y ~ x1 + x2 + x3 + x4 + x5 + x6 + x7 + x8 + x9 + x10 +
> x11 + x12 + x13 + x14, data=my.data.set, weights=wts )
> 
> And the output:
> 
>  summary( fit )
> Call:
> rpart(formula = y ~ x1 + x2 + x3 + x4 + x5 + x6 + x7 + x8 + x9 + x10 +
> x11 + x12 + x13 + x14, data =my.data.set, weights = wts)
>   n= 6530 
> 
>   CP nsplit rel error
> 1 NA      0        NA


Well, I tried out a self made exmple on a 6 year old laptop right now, 
and it works perfectly!
Hence, you have to give some more setails about your data, as Torsten 
already mentioned. E.g., start with the output of
str(my.data.set)
str(wts)

and perhaps this helps, otherwise, please make a small (as small as you 
can to reproduce) example available that reproduces the problem, e.g. on 
some web page.

Uwe LIgges


> Node number NA: NA observationsError in if (ff$complexity[i] < cp ||
> is.leaf[i]) cat("\n") else cat(",    complexity param=",  : 
>         missing value where TRUE/FALSE needed
> 
> 
> If I run this using a subset of 900 points, everything is fine.
> Similarly, if I run it using 1100 points, it dies. There are no missing
> values in the dataset. Is this simply a case where I should decrease cp?
> 
> Regards,
> Andrew
> 
> -----Original Message-----
> From: Torsten Hothorn [mailto:Torsten.Hothorn at rzmail.uni-erlangen.de] 
> Sent: Tuesday, September 19, 2006 4:45 PM
> To: Andrew Zachary
> Cc: r-help at stat.math.ethz.ch
> Subject: Re: [R] Problem with rpart
> 
> 
> On Tue, 19 Sep 2006, Andrew Zachary wrote:
> 
> 
>>Not sure if anyone has posted on this problem ... I want to use rpart 
>>to build a binary tree on a relatively large dataset with ~1400 data 
>>points and 15 predictors. But I've noticed that rpart fails almost 
>>immediately in the call to C_s_to_rp, as that code returns nonsense. 
>>Looking at the code itself isn't terribly helpful, and there don't 
>>seem to be any hard limits coded anywhere. Does anyone have a 
>>suggestion for what might be going on?
>>
> 
> 
> Andrew,
> 
> you need to give an _executable_ example illustrating your problem. What
> means `nonsense'?
> 
> Best,
> 
> Torsten
> 
> 
>>Thanks in advance for you help
>>Andrew Zachary
>>
>>----
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