On Wed, Jul 22, 2009 at 2:53 PM, Laurent Gautier<lgaut...@gmail.com> wrote:
> Skipper Seabold wrote:
>>
>> Hello all,
>>
>> Are RPy bugs still being accepted on the sourceforge page?
>
> They certainly are.
>
>> I think I found one when trying to do an rlm estimation.
>>
>> I can provide code to (possibly) reproduce; however, the short version
>> is this. Given the stackloss data from R datasets and a data frame
>> and formula given in the examples here
>> <http://sekhon.berkeley.edu/library/MASS/html/rlm.html>
>>
>> from rpy import r
>> r.library('MASS')
>> results1 = r.rlm(formula, data=frame, psi="psi.huber")
>>
>> # works correctly
>>
>> results2 = r.rlm(formula, data=frame, psi="psi.bisquare")
>>
>> # works correctly
>>
>> results3 = r.rlm(formula, data=frame, psi="psi.hampel")
>>
>> # raises exception
>>
>> The last one raises the following exception, though this works fine at
>> the R intepreter.
>>
>> RPy_RException: Error in x * wts : non-conformable arrays
>>
>> Anyone have any idea if this is user error or a bug?
>
> Unfortunately I don't, but someone else might.
>
> Note: Having a standalone example to demonstrate the bug is always good (I
> think that we are missing something in the first part here).
>
>
> L.
>
Thanks for the reply. I have a wrapper for RPy that makes the
interface similar to some statistical models code that I am working on
for SciPy, and this is how the bug comes up. The weird thing that I
discovered in trying to replicate is that it only comes up when x is
defined from another source and only for psi.hampel, even though it is
*exactly* the same as the x below. Very frustrating and odd. I can't
think of anything that would make the x array that I have different
from the one defined below. If anyone is interested in pursuing this
I can provide the rest of the code. On a first pass, the below
created the error though I had previously been working at the
interpreter. I couldn't replicate after but can replicate with the
arrays that are imported.
import rpy
from rpy import r
import numpy as np
data = rpy.as_list(r('stackloss'))
y = data[0]['stack.loss']
x = np.column_stack(np.array(data[0][name]) for name in data[0].keys()[0:-1])
x = np.column_stack((x,np.ones((len(x),1))))
# x is now a (21,4) array with a constant
formula = r('y~ x.1 + x.2 + x.3 + x.4 - 1')
frame = r.data_frame(y=y, x=x)
r.library('MASS')
results1 = r.rlm(formula, data=frame, psi='psi.huber')
results2 = r.rlm(formula, data=frame, psi='psi.bisquare')
# this works fine
results3 = r.rlm(formula, data=frame, psi='psi.hampel')
# this raises the exception when x is defined elsewhere though is
equivalent to the above x
RPy_RException: Error in x * wts : non-conformable arrays
Skipper
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