def evaluate4svm(labels, feats, params={'c': 1, 'kernal': 'gauss'}, Nsplit=2):
"""
Run Cross-validation to evaluate the SVM.
Parameters
----------
labels: 2d array
Data set labels.
feats: array
Data set feats.
params: dictionary
Search scope parameters.
Nsplit: int, default = 2
The n for n-fold cross validation.
"""
c = params.get('c')
if params.get('kernal' == 'gauss'):
kernal = GaussianKernel()
kernal.set_width(80)
elif params.get('kernal' == 'sigmoid'):
kernal = SigmoidKernel()
else:
kernal = LinearKernel()
split = CrossValidationSplitting(labels, Nsplit)
split.build_subsets()
accuracy = np.zeros(Nsplit)
time_test = np.zeros(accuracy.shape)
for i in range(Nsplit):
idx_train = split.generate_subset_inverse(i)
idx_test = split.generate_subset_indices(i)
feats.add_subset(idx_train)
labels.add_subset(idx_train)
print c, kernal, labels
svm = GMNPSVM(c, kernal, labels)
_ = svm.train(feats)
out = svm.apply(feats_test)
evaluator = MulticlassAccuracy()
accuracy[i] = evaluator.evaluate(out, labels_test)
feats.remove_subset()
labels.remove_subset()
feats.add_subset(idx_test)
labels.add_subset(idx_test)
t_start = time.clock()
time_test[i] = (time.clock() - t_start) / labels.get_num_labels()
feats.remove_subset()
labels.remove_subset()
return accuracy
