def _fit(self, X, y, parameter_iterable):
"""Actual fitting, performing the search over parameters."""
estimator = self.estimator
cv = self.cv
n_samples = _num_samples(X)
X, y = check_arrays(X, y, allow_lists=True, sparse_format='csr')
if y is not None:
if len(y) != n_samples:
raise ValueError('Target variable (y) has a different number '
'of samples (%i) than data (X: %i samples)'
% (len(y), n_samples))
y = np.asarray(y)
cv = check_cv(cv, X, y, classifier=is_classifier(estimator))
if not self.dataset_filenames:
self.save_dataset_filename(X, y, cv)
dataset_filenames = self.dataset_filenames
client = Client()
lb_view = client.load_balanced_view()
if self.verbose > 0:
print("Number of CPU core %d" % len(client.ids()))
self.tasks = [([lb_view.apply(evaluate, estimator, dataset_filename, params)
for dataset_filename in dataset_filenames], params)
for params in parameter_iterable]
if self.sync:
self.wait()
self.set_grid_scores()
self.set_best_score_params()
if self.refit:
self.set_best_estimator(estimator)
return self
