def test_balance_weights():
weights = balance_weights([0, 0, 1, 1])
assert_array_equal(weights, [1., 1., 1., 1.])
weights = balance_weights([0, 1, 1, 1, 1])
assert_array_equal(weights, [1., 0.25, 0.25, 0.25, 0.25])
weights = balance_weights([0, 0])
assert_array_equal(weights, [1., 1.])
def test_balance_weights():
weights = balance_weights([0, 0, 1, 1])
assert_array_equal(weights, [1., 1., 1., 1.])
weights = balance_weights([0, 1, 1, 1, 1])
assert_array_equal(weights, [1., 0.25, 0.25, 0.25, 0.25])
weights = balance_weights([0, 0])
assert_array_equal(weights, [1., 1.])
def weighted_randomforest(data, targets, tree_num=TREE_NUM):
model = RandomForestClassifier(n_estimators=tree_num,
n_jobs=4,
max_features=data.shape[1] / 2 + 1,
verbose=0,
compute_importances=True)
model.fit(data, targets, balance_weights(targets))
return model
def weighted_randomforest(data, targets, tree_num=TREE_NUM):
model = RandomForestClassifier(n_estimators=tree_num,
n_jobs=4,
max_features=data.shape[1]/2+1,
verbose=0,
compute_importances=True)
model.fit(data, targets, balance_weights(targets))
return model
def test_unbalanced_iris():
"""Check class rebalancing."""
unbalanced_X = iris.data[:125]
unbalanced_y = iris.target[:125]
sample_weight = balance_weights(unbalanced_y)
clf = tree.DecisionTreeClassifier()
clf.fit(unbalanced_X, unbalanced_y, sample_weight=sample_weight)
assert_almost_equal(clf.predict(unbalanced_X), unbalanced_y)
def test_unbalanced_iris():
"""Check class rebalancing."""
unbalanced_X = iris.data[:125]
unbalanced_y = iris.target[:125]
sample_weight = balance_weights(unbalanced_y)
clf = tree.DecisionTreeClassifier()
clf.fit(unbalanced_X, unbalanced_y, sample_weight=sample_weight)
assert_almost_equal(clf.predict(unbalanced_X), unbalanced_y)
def __init__(self, stories=None, df=None):
self.stories = stories
if self.stories is not None: # training set
candidates = df[['candidate', 'story_id']].to_dict('records')
y = np.array([get_relevance(candidate, self.stories)
for candidate in candidates])
self.target = pd.get_dummies(y)
self.y = y
self.sample_weight = balance_weights(y)
def _attempt(clf, X_train, y_train, X_test, y_test, weighted=True):
weights = None
if weighted:
weights = balance_weights(y_train)
clf.fit(X_train, y_train, sample_weight=weights)
pred = clf.predict(X_test)
print metrics.classification_report(y_test, pred, target_names=['high', 'low'])
def test_unbalanced_iris():
"""Check class rebalancing."""
unbalanced_X = iris.data[:125]
unbalanced_y = iris.target[:125]
sample_weight = balance_weights(unbalanced_y)
for name, TreeClassifier in CLF_TREES.items():
clf = TreeClassifier(random_state=0)
clf.fit(unbalanced_X, unbalanced_y, sample_weight=sample_weight)
assert_almost_equal(clf.predict(unbalanced_X), unbalanced_y)
def test_unbalanced_iris():
"""Check class rebalancing."""
unbalanced_X = iris.data[:125]
unbalanced_y = iris.target[:125]
sample_weight = balance_weights(unbalanced_y)
for name, TreeClassifier in CLF_TREES.items():
clf = TreeClassifier(random_state=0)
clf.fit(unbalanced_X, unbalanced_y, sample_weight=sample_weight)
assert_almost_equal(clf.predict(unbalanced_X), unbalanced_y)
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')
self.scorer_ = _deprecate_loss_and_score_funcs(self.loss_func,
self.score_func,
self.scoring)
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 self.verbose > 0:
if isinstance(parameter_iterable, Sized):
n_candidates = len(parameter_iterable)
print("Fitting {0} folds for each of {1} candidates, totalling"
" {2} fits".format(len(cv), n_candidates,
n_candidates * len(cv)))
base_estimator = clone(self.estimator)
pre_dispatch = self.pre_dispatch
out = Parallel(n_jobs=self.n_jobs,
verbose=self.verbose,
pre_dispatch=pre_dispatch)(delayed(fit_grid_point)(
X, y, base_estimator, parameters, train, test,
self.scorer_, self.verbose, **{
'sample_weight': balance_weights(y[train])
}) for parameters in parameter_iterable
for train, test in cv)
# Out is a list of triplet: score, estimator, n_test_samples
n_fits = len(out)
n_folds = len(cv)
scores = list()
grid_scores = list()
for grid_start in range(0, n_fits, n_folds):
n_test_samples = 0
score = 0
all_scores = []
for this_score, parameters, this_n_test_samples in \
out[grid_start:grid_start + n_folds]:
all_scores.append(this_score)
if self.iid:
this_score *= this_n_test_samples
n_test_samples += this_n_test_samples
score += this_score
if self.iid:
score /= float(n_test_samples)
else:
score /= float(n_folds)
scores.append((score, parameters))
# TODO: shall we also store the test_fold_sizes?
grid_scores.append(
_CVScoreTuple(parameters, score, np.array(all_scores)))
# Store the computed scores
self.grid_scores_ = grid_scores
# Find the best parameters by comparing on the mean validation score:
# note that `sorted` is deterministic in the way it breaks ties
best = sorted(grid_scores,
key=lambda x: x.mean_validation_score,
reverse=True)[0]
self.best_params_ = best.parameters
self.best_score_ = best.mean_validation_score
if self.refit:
# fit the best estimator using the entire dataset
# clone first to work around broken estimators
best_estimator = clone(base_estimator).set_params(
**best.parameters)
if y is not None:
best_estimator.fit(X,
y,
sample_weight=balance_weights(y),
**self.fit_params)
else:
best_estimator.fit(X, **self.fit_params)
self.best_estimator_ = best_estimator
return self
data_y = train["target"]
train_X, val_X, train_y, val_y = train_test_split(data_X, data_y,
test_size = 0.33, random_state = 42)
test_X = test.drop(["id"], axis = 1)
# <codecell>
#rf = GridSearchCV(rfClassifier(), [{'n_estimators': [10, 50, 100, 150, 200, 300, 500]},
#{'max_features': ["sqrt", "log2", None]}])
rf = rfClassifier(n_estimators = 500, max_features = 18, verbose = 1)
# <codecell>
rf_fit = rf.fit(train_X, train_y, sample_weight = balance_weights(train_y))
# <codecell>
rf_fit
# <codecell>
rf_prob = rf_fit.score(val_X, val_y)
# <codecell>
rf_prob
# <codecell>
def calculate_weights(self, classes):
return balance_weights(classes)
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')
self.scorer_ = _deprecate_loss_and_score_funcs(
self.loss_func, self.score_func, self.scoring)
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 self.verbose > 0:
if isinstance(parameter_iterable, Sized):
n_candidates = len(parameter_iterable)
print("Fitting {0} folds for each of {1} candidates, totalling"
" {2} fits".format(len(cv), n_candidates,
n_candidates * len(cv)))
base_estimator = clone(self.estimator)
pre_dispatch = self.pre_dispatch
out = Parallel(
n_jobs=self.n_jobs, verbose=self.verbose,
pre_dispatch=pre_dispatch)(
delayed(fit_grid_point)(
X, y, base_estimator, parameters, train, test, self.scorer_,
self.verbose, **{'sample_weight': balance_weights(y[train])}) for parameters in
parameter_iterable for train, test in cv)
# Out is a list of triplet: score, estimator, n_test_samples
n_fits = len(out)
n_folds = len(cv)
scores = list()
grid_scores = list()
for grid_start in range(0, n_fits, n_folds):
n_test_samples = 0
score = 0
all_scores = []
for this_score, parameters, this_n_test_samples in \
out[grid_start:grid_start + n_folds]:
all_scores.append(this_score)
if self.iid:
this_score *= this_n_test_samples
n_test_samples += this_n_test_samples
score += this_score
if self.iid:
score /= float(n_test_samples)
else:
score /= float(n_folds)
scores.append((score, parameters))
# TODO: shall we also store the test_fold_sizes?
grid_scores.append(_CVScoreTuple(
parameters,
score,
np.array(all_scores)))
# Store the computed scores
self.grid_scores_ = grid_scores
# Find the best parameters by comparing on the mean validation score:
# note that `sorted` is deterministic in the way it breaks ties
best = sorted(grid_scores, key=lambda x: x.mean_validation_score,
reverse=True)[0]
self.best_params_ = best.parameters
self.best_score_ = best.mean_validation_score
if self.refit:
# fit the best estimator using the entire dataset
# clone first to work around broken estimators
best_estimator = clone(base_estimator).set_params(
**best.parameters)
if y is not None:
best_estimator.fit(X, y, sample_weight = balance_weights(y),**self.fit_params)
else:
best_estimator.fit(X, **self.fit_params)
self.best_estimator_ = best_estimator
return self
def calculate_weights(self, classes):
return balance_weights(classes)
