Scikit-learn GridSearch donner “ValueError: multiclass format n'est pas pris en charge” erreur

Je suis en train d'utiliser GridSearch pour l'estimation des paramètres de LinearSVC() comme suit -

clf_SVM = LinearSVC()
params = {
          'C': [0.5, 1.0, 1.5],
          'tol': [1e-3, 1e-4, 1e-5],
          'multi_class': ['ovr', 'crammer_singer'],
          }
gs = GridSearchCV(clf_SVM, params, cv=5, scoring='roc_auc')
gs.fit(corpus1, y)

corpus1 a la forme (1726, 7001) et y a de la forme (1726,)

C'est un multiclasse, et y a des valeurs de 0 à 3, à la fois inclusive, c'est à dire il y a quatre classes.

Mais ce qui me donne l'erreur suivante -

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-220-0c627bda0543> in <module>()
5           }
6 gs = GridSearchCV(clf_SVM, params, cv=5, scoring='roc_auc')
----> 7 gs.fit(corpus1, y)
/usr/local/lib/python2.7/dist-packages/sklearn/grid_search.pyc in fit(self, X, y)
594 
595         """
--> 596         return self._fit(X, y, ParameterGrid(self.param_grid))
597 
598 
/usr/local/lib/python2.7/dist-packages/sklearn/grid_search.pyc in _fit(self, X, y, parameter_iterable)
376                                     train, test, self.verbose, parameters,
377                                     self.fit_params, return_parameters=True)
--> 378             for parameters in parameter_iterable
379             for train, test in cv)
380 
/usr/local/lib/python2.7/dist-packages/sklearn/externals/joblib/parallel.pyc in __call__(self, iterable)
651             self._iterating = True
652             for function, args, kwargs in iterable:
--> 653                 self.dispatch(function, args, kwargs)
654 
655             if pre_dispatch == "all" or n_jobs == 1:
/usr/local/lib/python2.7/dist-packages/sklearn/externals/joblib/parallel.pyc in dispatch(self, func, args, kwargs)
398         """
399         if self._pool is None:
--> 400             job = ImmediateApply(func, args, kwargs)
401             index = len(self._jobs)
402             if not _verbosity_filter(index, self.verbose):
/usr/local/lib/python2.7/dist-packages/sklearn/externals/joblib/parallel.pyc in __init__(self, func, args, kwargs)
136         # Don't delay the application, to avoid keeping the input
137         # arguments in memory
--> 138         self.results = func(*args, **kwargs)
139 
140     def get(self):
/usr/local/lib/python2.7/dist-packages/sklearn/cross_validation.pyc in _fit_and_score(estimator, X, y, scorer, train, test, verbose, parameters, fit_params, return_train_score, return_parameters)
1238     else:
1239         estimator.fit(X_train, y_train, **fit_params)
-> 1240     test_score = _score(estimator, X_test, y_test, scorer)
1241     if return_train_score:
1242         train_score = _score(estimator, X_train, y_train, scorer)
/usr/local/lib/python2.7/dist-packages/sklearn/cross_validation.pyc in _score(estimator, X_test, y_test, scorer)
1294         score = scorer(estimator, X_test)
1295     else:
-> 1296         score = scorer(estimator, X_test, y_test)
1297     if not isinstance(score, numbers.Number):
1298         raise ValueError("scoring must return a number, got %s (%s) instead."
/usr/local/lib/python2.7/dist-packages/sklearn/metrics/scorer.pyc in __call__(self, clf, X, y)
136         y_type = type_of_target(y)
137         if y_type not in ("binary", "multilabel-indicator"):
--> 138             raise ValueError("{0} format is not supported".format(y_type))
139 
140         try:
ValueError: multiclass format is not supported

OriginalL'auteur theharshest | 2014-10-06