[pymvpa] LinearSVM Classification Warning

Geethmala geethmala at gmail.com
Tue Feb 2 19:40:11 UTC 2010


code snippet:
########

dataset = dataset.selectSamples(
                N.array([l in [1, 2, 3, 4, 5] for l in dataset.labels],
                        dtype='bool'))

cv = CrossValidatedTransferError(
                        TransferError(LinearCSVMC()),
                        CustomSplitter([([0,1],[2,3,4,5,6,7]),
([2,3],[0,1,4,5,6,7]), ([4,5],[0,1,2,3,6,7]), ([6,7],[0,1,2,3,4,5])],
attr='chunks')
                        )

sl = Searchlight(cv, radius=11.0)

# run searchlight on example dataset and retrieve error map
sl_map = sl(dataset)

print 'Best performing sphere error:', max(sl_map)
############

Thanks,
Geethmala

On Tue, Feb 2, 2010 at 2:33 PM, Matthias Ekman <Matthias.Ekman at nf.mpg.de>wrote:

> wild guess :):
> because you did some selection like:
>
> ds = ds.selectSamples(N.array([l in [3,4] for l in
> ds.labels],dtype='bool'))
>
> before training/testing?
> May be you could post all relevant code parts?
>
> btw, is there any reason why your data is not counterbalanced?
>
> cheers,
>  Matthias
>
> Geethmala wrote:
> > Yes, but what is interesting is why is it not showing the warning for
> other
> > labels? Why only 3?
> >
> > Thanks,
> > Geethmala
> >
> > On Tue, Feb 2, 2010 at 2:19 PM, Matthias Ekman <Matthias.Ekman at nf.mpg.de
> >wrote:
> >
> >> Hi,
> >>
> >> i assume you already tracked the problem, right? ;-) ... since there a
> >> no samples (of class 3) in chunk, 0, 4, 5... exactly what
> >>
> >>>>>>  Classifier LinearCSVMC(kernel_type='linear', svm_impl='C_SVC')
> >>>>>>  wasn't trained to classify labels Set([3.0]) present in testing
> >>>>>>  dataset. Make sure that you have not mixed order/names of the
> >>>>>>  arguments anywhere
> >> says.
> >>
> >> cheers,
> >>  Matthias
> >>
> >> Geethmala wrote:
> >>> Here you go,
> >>>
> >>> Dataset / float32 153 x 40656
> >>> uniq: 8 chunks 5 labels
> >>> stats: mean=-0.0255406 std=0.994264 var=0.98856 min=-6.94855
> max=6.71638
> >>>
> >>> Counts of labels in each chunk:
> >>>   chunks\labels 1.0 2.0 3.0 4.0 5.0
> >>>                 --- --- --- --- ---
> >>>       0.0        3   6   0   9   6
> >>>       1.0        3   0   6   3   6
> >>>       2.0        3   6   3   3   3
> >>>       3.0        0   6   9   0   6
> >>>       4.0        6   0   0   3   3
> >>>       5.0        6   3   0   9   0
> >>>       6.0        6   6   3   6   0
> >>>       7.0        3   3   9   0   6
> >>>
> >>> Summary per label across chunks
> >>>   label mean  std min max #chunks
> >>>    1    3.75 1.98  0   6     7
> >>>    2    3.75 2.49  0   6     6
> >>>    3    3.75  3.6  0   9     5
> >>>    4    4.12 3.33  0   9     6
> >>>    5    3.75 2.49  0   6     6
> >>>
> >>> Summary per chunk across labels
> >>>   chunk mean  std min max #labels
> >>>    0     4.8 3.06  0   9     4
> >>>    1     3.6 2.24  0   6     4
> >>>    2     3.6  1.2  3   6     5
> >>>    3     4.2  3.6  0   9     3
> >>>    4     2.4 2.24  0   6     3
> >>>    5     3.6  3.5  0   9     3
> >>>    6     4.2  2.4  0   6     4
> >>>    7     4.2 3.06  0   9     4
> >>>
> >>>
> >>> Thanks,
> >>> Geethmala
> >>>
> >>> On Tue, Feb 2, 2010 at 2:11 PM, Matthias Ekman <
> Matthias.Ekman at nf.mpg.de
> >>> wrote:
> >>>
> >>>> Hi,
> >>>>
> >>>> could you please post:
> >>>> print ds.summary()
> >>>>
> >>>> .. just to make sure, that there are samples belonging to class 3 :)
> >>>>
> >>>>
> >>>> Matthias
> >>>>
> >>>> Geethmala wrote:
> >>>>> No, I don't have a mix of them. They are all integer values.
> >>>>>
> >>>>> Thanks,
> >>>>> Geethmala
> >>>>>
> >>>>> On Tue, Feb 2, 2010 at 1:59 PM, Yaroslav Halchenko <
> >>>> debian at onerussian.com>wrote:
> >>>>>> it means that
> >>>>>>
> >>>>>>  Classifier LinearCSVMC(kernel_type='linear', svm_impl='C_SVC')
> >>>>>>  wasn't trained to classify labels Set([3.0]) present in testing
> >>>>>>  dataset. Make sure that you have not mixed order/names of the
> >>>>>>  arguments anywhere
> >>>>>>
> >>>>>> Also test if you don't have a mix of float and int labels in your
> >>>>>> datasets (as I remember you are manually composing those).
> >>>>>>
> >>>>>>
> >>>>>> On Tue, 02 Feb 2010, Geethmala wrote:
> >>>>>>
> >>>>>>>    Hi,
> >>>>>>>    I get the following warning when I run LinearCSVMC.
> >>>>>>>    WARNING: Classifier LinearCSVMC(kernel_type='linear',
> >>>>>> svm_impl='C_SVC')
> >>>>>>>    wasn't trained to classify labels Set([3.0]) present in testing
> >>>>>>>    dataset. Make sure that you have not mixed order/names of the
> >>>>>> arguments
> >>>>>>>    anywhere
> >>>>>>>    What does this warning mean?
> >>>>>>>    Thanks,
> >>>>>>>    Geethmala
> >>>>>>> _______________________________________________
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> >>>>>> --
> >>>>>>                                  .-.
> >>>>>> =------------------------------   /v\  ----------------------------=
> >>>>>> Keep in touch                    // \\     (yoh@|www.)
> onerussian.com
> >>>>>> Yaroslav Halchenko              /(   )\               ICQ#: 60653192
> >>>>>>                   Linux User    ^^-^^    [175555]
> >>>>>>
> >>>>>>
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