def predict_proba(self, X):
"""Return probability estimates for the test data X.
Parameters
----------
X : array-like, shape (n_query, n_features), \
or (n_query, n_indexed) if metric == 'precomputed'
Test samples.
Returns
-------
proba : array of shape (n_samples, n_classes), or a list of n_outputs
of such arrays if n_outputs > 1.
The class probabilities of the input samples. Classes are ordered
by lexicographic order.
"""
X = check_array(X, accept_sparse='csr')
dists, inds = self.kneighbors(X, return_distance=True)
classes = self.fit_y_[inds]
dists_array = np.empty((X.shape[0], self.n_classes_))
# TODO: check if a more efficient implementation can be done
for c in self.classes_:
dists_array[:, c] = np.ma.MaskedArray(dists,
classes != c).mean(axis=1)
probas = softmax(1. / dists_array)
return probas
def predict_proba_ensemble_weighted(classifier_ensemble, weights, X):
"""Estimates the posterior probabilities for each sample in X.
Parameters
----------
classifier_ensemble : list of shape = [n_classifiers]
containing the ensemble of classifiers used to estimate the probabilities.
weights : array of shape = [n_samples, n_classifiers]
Weights associated to each base classifier for each sample
X : array of shape = [n_samples, n_features]
The input data.
Returns
-------
list_proba : array of shape = [n_classifiers, n_samples, n_classes]
probabilities predicted by each base classifier in the ensemble for all samples in X.
"""
if weights.ndim == 1:
weights = np.atleast_2d(weights)
ensemble_proba = _get_ensemble_probabilities(classifier_ensemble, X)
n_classifiers = ensemble_proba.shape[0]
if n_classifiers != weights.shape[1]:
raise ValueError(
'The number of weights should be equal to the number of base classifiers in the ensemble.'
'The number of classifiers is {},'
' and the number of weights is {}'.format(n_classifiers,
weights.shape[1]))
predicted_proba = np.einsum('ijk,ji->jk', ensemble_proba,
weights) / n_classifiers
return softmax(predicted_proba)
def aggregate_proba_ensemble_weighted(ensemble_proba, weights):
predicted_proba = ensemble_proba * np.expand_dims(weights, axis=2)
predicted_proba = predicted_proba.mean(axis=1)
return softmax(predicted_proba)
def test_softmax(vector, expected):
assert np.isclose(softmax(vector), expected, atol=0.001).all()
def test_softmax_sum_to_one():
test = np.random.rand(10)
assert np.allclose(np.sum(softmax(test)), 1.0, atol=0.001)
