[pymvpa] kNN and sensitivity map

[marco tettamanti]

Dear all,
since kNN performs best on a particular dataset, I am trying to obtain a 
sensitivity map based on the code that I have used for other classifiers. 
However, I receive an error message, and I am not able to proceed further.
I have been struggling with the documentation, but I still cannot find any 
solutions for this problem.
Can somebody please help?
Thank you and best wishes,
Marco



This is the relevant snippet:

{fds == fmri dataset}
clf = kNN(k=2, dfx=one_minus_correlation, voting='majority')
partitioner = HalfPartitioner()
fraction=1
fselaov = SensitivityBasedFeatureSelection(OneWayAnova(), 
FractionTailSelector(fraction, mode='select', tail='upper'))
fclf = FeatureSelectionClassifier(clf, fselaov)
fselcvte = CrossValidation(fclf, partitioner, errorfx=lambda p, t: np.mean(p == 
t), postproc=mean_sample(), enable_ca=['confusion', 'stats'])
res_fsel = fselcvte(fds)
sensana = fclf.get_sensitivity_analyzer(postproc=maxofabs_sample())




This is the error message:

---------------------------------------------------------------------------
NotImplementedError                        Traceback (most recent call last)
<ipython-input-32-2e8317c1b278>  in<module>() ----> 1sensana = fclf.get_sensitivity_analyzer(postproc=maxofabs_sample())
2  #sensana = fclf.get_sensitivity_analyzer(postproc=absolute_features())
3  #sensana = fclf.get_sensitivity_analyzer(postproc=mean_sample())
4  cv_sensana=  RepeatedMeasure(sensana,  ChainNode((partitioner,  Splitter('partitions',  attr_values=(1,)))))
5  sens=  cv_sensana(fds)

/usr/lib/python2.7/dist-packages/mvpa2/misc/args.pyc  indo_group_kwargs(self, *args_, **kwargs_) 73 if passthrough:    kwargs__[k]  =  skwargs
74                  if  assign:  setattr(self,  '_%s'  %  k,  skwargs)
---> 75return method(self,  *args_,  **kwargs__)
76          do_group_kwargs.func_name=  method.func_name
77          return  do_group_kwargs

/usr/lib/python2.7/dist-packages/mvpa2/clfs/meta.pyc  inget_sensitivity_analyzer(self, slave_kwargs, **kwargs) 329 return 
self.__sa_class__( 330 self,
--> 331analyzer=self.__clf.get_sensitivity_analyzer(**slave_kwargs),
332                  **kwargs)
333  

/usr/lib/python2.7/dist-packages/mvpa2/clfs/base.pyc  inget_sensitivity_analyzer(self, **kwargs) 492 """Factory method to return an 
appropriate sensitivity analyzer for 493 the respective classifier.""" --> 
494raise NotImplementedError
495  
496  

NotImplementedError:




This are the code and OS versions:

Current date:   2016-05-31 17:22
PyMVPA:
  Version:       2.5.0
  Hash:          6a9d4060ad863f99170801854c272b61af51f015
  Path:          /usr/lib/python2.7/dist-packages/mvpa2/__init__.pyc
  Version control (GIT):
  GIT information could not be obtained due "/usr/lib/python2.7/dist-packages/mvpa2/.. is not under GIT"
SYSTEM:
  OS:            posix Linux 4.3.0-1-amd64 #1 SMP Debian 4.3.3-7 (2016-01-19)
  Distribution:  debian/stretch/sid
EXTERNALS:
  Present:       atlas_fsl, cPickle, ctypes, good scipy.stats.rv_continuous._reduce_func(floc,fscale), good scipy.stats.rv_discrete.ppf, griddata, gzip, h5py, hdf5, ipython, joblib, liblapack.so, libsvm, libsvm verbosity control, lxml, matplotlib, mdp, mdp ge 2.4, mock, nibabel, nipy, nose, numpy, numpy_correct_unique, pprocess, pylab, pylab plottable, pywt, pywt wp reconstruct, reportlab, running ipython env, scipy, scipy.weave, sg ge 0.6.4, sg ge 0.6.5, sg_fixedcachesize, shogun, shogun.mpd, shogun.svmocas, skl, statsmodels
  Absent:        atlas_pymvpa, cran-energy, datalad, elasticnet, glmnet, good scipy.stats.rdist, hcluster, lars, mass, nipy.neurospin, numpydoc, openopt, pywt wp reconstruct fixed, rpy2, shogun.krr, shogun.lightsvm, shogun.svrlight, weave
  Versions of critical externals:
   ctypes      : 1.1.0
   h5py        : 2.5.0
   hdf5        : 1.8.13
   ipython     : 2.3.0
   joblib      : 0.9.4
   lxml        : 3.4.4
   matplotlib  : 1.4.2
   mdp         : 3.5
   mock        : 1.3.0
   nibabel     : 2.0.2
   nipy        : 0.4.0.dev
   numpy       : 1.8.2
   pprocess    : 0.5
   reportlab   : 3.2.0
   scipy       : 0.14.1
   shogun      : 3.2.0
   shogun:full : 3.2.0_2014-2-17_18:46
   shogun:rev  : 197120
   skl         : 0.17.1
  Matplotlib backend: module://IPython.kernel.zmq.pylab.backend_inline


-- 
Marco Tettamanti, Ph.D.
Nuclear Medicine Department & Division of Neuroscience
San Raffaele Scientific Institute
Via Olgettina 58
I-20132 Milano, Italy
Phone ++39-02-26434888
Fax ++39-02-26434892
Email: tettamanti.marco at hsr.it
Skype: mtettamanti