/usr/lib/python3/dist-packages/sklearn/linear_model/tests/test_sgd.py is in python3-sklearn 0.17.0-4.
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import unittest
import numpy as np
import scipy.sparse as sp
from sklearn.utils.testing import assert_array_equal
from sklearn.utils.testing import assert_almost_equal
from sklearn.utils.testing import assert_array_almost_equal
from sklearn.utils.testing import assert_greater
from sklearn.utils.testing import assert_less
from sklearn.utils.testing import raises
from sklearn.utils.testing import assert_raises
from sklearn.utils.testing import assert_false, assert_true
from sklearn.utils.testing import assert_equal
from sklearn.utils.testing import assert_raises_regexp
from sklearn.utils.testing import ignore_warnings
from sklearn import linear_model, datasets, metrics
from sklearn.base import clone
from sklearn.linear_model import SGDClassifier, SGDRegressor
from sklearn.preprocessing import LabelEncoder, scale, MinMaxScaler
class SparseSGDClassifier(SGDClassifier):
def fit(self, X, y, *args, **kw):
X = sp.csr_matrix(X)
return super(SparseSGDClassifier, self).fit(X, y, *args, **kw)
def partial_fit(self, X, y, *args, **kw):
X = sp.csr_matrix(X)
return super(SparseSGDClassifier, self).partial_fit(X, y, *args, **kw)
def decision_function(self, X):
X = sp.csr_matrix(X)
return super(SparseSGDClassifier, self).decision_function(X)
def predict_proba(self, X):
X = sp.csr_matrix(X)
return super(SparseSGDClassifier, self).predict_proba(X)
class SparseSGDRegressor(SGDRegressor):
def fit(self, X, y, *args, **kw):
X = sp.csr_matrix(X)
return SGDRegressor.fit(self, X, y, *args, **kw)
def partial_fit(self, X, y, *args, **kw):
X = sp.csr_matrix(X)
return SGDRegressor.partial_fit(self, X, y, *args, **kw)
def decision_function(self, X, *args, **kw):
X = sp.csr_matrix(X)
return SGDRegressor.decision_function(self, X, *args, **kw)
# Test Data
# test sample 1
X = np.array([[-2, -1], [-1, -1], [-1, -2], [1, 1], [1, 2], [2, 1]])
Y = [1, 1, 1, 2, 2, 2]
T = np.array([[-1, -1], [2, 2], [3, 2]])
true_result = [1, 2, 2]
# test sample 2; string class labels
X2 = np.array([[-1, 1], [-0.75, 0.5], [-1.5, 1.5],
[1, 1], [0.75, 0.5], [1.5, 1.5],
[-1, -1], [0, -0.5], [1, -1]])
Y2 = ["one"] * 3 + ["two"] * 3 + ["three"] * 3
T2 = np.array([[-1.5, 0.5], [1, 2], [0, -2]])
true_result2 = ["one", "two", "three"]
# test sample 3
X3 = np.array([[1, 1, 0, 0, 0, 0], [1, 1, 0, 0, 0, 0],
[0, 0, 1, 0, 0, 0], [0, 0, 1, 0, 0, 0],
[0, 0, 0, 0, 1, 1], [0, 0, 0, 0, 1, 1],
[0, 0, 0, 1, 0, 0], [0, 0, 0, 1, 0, 0]])
Y3 = np.array([1, 1, 1, 1, 2, 2, 2, 2])
# test sample 4 - two more or less redundent feature groups
X4 = np.array([[1, 0.9, 0.8, 0, 0, 0], [1, .84, .98, 0, 0, 0],
[1, .96, .88, 0, 0, 0], [1, .91, .99, 0, 0, 0],
[0, 0, 0, .89, .91, 1], [0, 0, 0, .79, .84, 1],
[0, 0, 0, .91, .95, 1], [0, 0, 0, .93, 1, 1]])
Y4 = np.array([1, 1, 1, 1, 2, 2, 2, 2])
iris = datasets.load_iris()
# test sample 5 - test sample 1 as binary classification problem
X5 = np.array([[-2, -1], [-1, -1], [-1, -2], [1, 1], [1, 2], [2, 1]])
Y5 = [1, 1, 1, 2, 2, 2]
true_result5 = [0, 1, 1]
# Classification Test Case
class CommonTest(object):
def factory(self, **kwargs):
if "random_state" not in kwargs:
kwargs["random_state"] = 42
return self.factory_class(**kwargs)
# a simple implementation of ASGD to use for testing
# uses squared loss to find the gradient
def asgd(self, X, y, eta, alpha, weight_init=None, intercept_init=0.0):
if weight_init is None:
weights = np.zeros(X.shape[1])
else:
weights = weight_init
average_weights = np.zeros(X.shape[1])
intercept = intercept_init
average_intercept = 0.0
decay = 1.0
# sparse data has a fixed decay of .01
if (isinstance(self, SparseSGDClassifierTestCase) or
isinstance(self, SparseSGDRegressorTestCase)):
decay = .01
for i, entry in enumerate(X):
p = np.dot(entry, weights)
p += intercept
gradient = p - y[i]
weights *= 1.0 - (eta * alpha)
weights += -(eta * gradient * entry)
intercept += -(eta * gradient) * decay
average_weights *= i
average_weights += weights
average_weights /= i + 1.0
average_intercept *= i
average_intercept += intercept
average_intercept /= i + 1.0
return average_weights, average_intercept
def _test_warm_start(self, X, Y, lr):
# Test that explicit warm restart...
clf = self.factory(alpha=0.01, eta0=0.01, n_iter=5, shuffle=False,
learning_rate=lr)
clf.fit(X, Y)
clf2 = self.factory(alpha=0.001, eta0=0.01, n_iter=5, shuffle=False,
learning_rate=lr)
clf2.fit(X, Y,
coef_init=clf.coef_.copy(),
intercept_init=clf.intercept_.copy())
# ... and implicit warm restart are equivalent.
clf3 = self.factory(alpha=0.01, eta0=0.01, n_iter=5, shuffle=False,
warm_start=True, learning_rate=lr)
clf3.fit(X, Y)
assert_equal(clf3.t_, clf.t_)
assert_array_almost_equal(clf3.coef_, clf.coef_)
clf3.set_params(alpha=0.001)
clf3.fit(X, Y)
assert_equal(clf3.t_, clf2.t_)
assert_array_almost_equal(clf3.coef_, clf2.coef_)
def test_warm_start_constant(self):
self._test_warm_start(X, Y, "constant")
def test_warm_start_invscaling(self):
self._test_warm_start(X, Y, "invscaling")
def test_warm_start_optimal(self):
self._test_warm_start(X, Y, "optimal")
def test_input_format(self):
# Input format tests.
clf = self.factory(alpha=0.01, n_iter=5,
shuffle=False)
clf.fit(X, Y)
Y_ = np.array(Y)[:, np.newaxis]
Y_ = np.c_[Y_, Y_]
assert_raises(ValueError, clf.fit, X, Y_)
def test_clone(self):
# Test whether clone works ok.
clf = self.factory(alpha=0.01, n_iter=5, penalty='l1')
clf = clone(clf)
clf.set_params(penalty='l2')
clf.fit(X, Y)
clf2 = self.factory(alpha=0.01, n_iter=5, penalty='l2')
clf2.fit(X, Y)
assert_array_equal(clf.coef_, clf2.coef_)
def test_plain_has_no_average_attr(self):
clf = self.factory(average=True, eta0=.01)
clf.fit(X, Y)
assert_true(hasattr(clf, 'average_coef_'))
assert_true(hasattr(clf, 'average_intercept_'))
assert_true(hasattr(clf, 'standard_intercept_'))
assert_true(hasattr(clf, 'standard_coef_'))
clf = self.factory()
clf.fit(X, Y)
assert_false(hasattr(clf, 'average_coef_'))
assert_false(hasattr(clf, 'average_intercept_'))
assert_false(hasattr(clf, 'standard_intercept_'))
assert_false(hasattr(clf, 'standard_coef_'))
def test_late_onset_averaging_not_reached(self):
clf1 = self.factory(average=600)
clf2 = self.factory()
for _ in range(100):
if isinstance(clf1, SGDClassifier):
clf1.partial_fit(X, Y, classes=np.unique(Y))
clf2.partial_fit(X, Y, classes=np.unique(Y))
else:
clf1.partial_fit(X, Y)
clf2.partial_fit(X, Y)
assert_array_almost_equal(clf1.coef_, clf2.coef_, decimal=16)
assert_almost_equal(clf1.intercept_, clf2.intercept_, decimal=16)
def test_late_onset_averaging_reached(self):
eta0 = .001
alpha = .0001
Y_encode = np.array(Y)
Y_encode[Y_encode == 1] = -1.0
Y_encode[Y_encode == 2] = 1.0
clf1 = self.factory(average=7, learning_rate="constant",
loss='squared_loss', eta0=eta0,
alpha=alpha, n_iter=2, shuffle=False)
clf2 = self.factory(average=0, learning_rate="constant",
loss='squared_loss', eta0=eta0,
alpha=alpha, n_iter=1, shuffle=False)
clf1.fit(X, Y_encode)
clf2.fit(X, Y_encode)
average_weights, average_intercept = \
self.asgd(X, Y_encode, eta0, alpha,
weight_init=clf2.coef_.ravel(),
intercept_init=clf2.intercept_)
assert_array_almost_equal(clf1.coef_.ravel(),
average_weights.ravel(),
decimal=16)
assert_almost_equal(clf1.intercept_, average_intercept, decimal=16)
@raises(ValueError)
def test_sgd_bad_alpha_for_optimal_learning_rate(self):
# Check whether expected ValueError on bad alpha, i.e. 0
# since alpha is used to compute the optimal learning rate
self.factory(alpha=0, learning_rate="optimal")
class DenseSGDClassifierTestCase(unittest.TestCase, CommonTest):
"""Test suite for the dense representation variant of SGD"""
factory_class = SGDClassifier
def test_sgd(self):
# Check that SGD gives any results :-)
for loss in ("hinge", "squared_hinge", "log", "modified_huber"):
clf = self.factory(penalty='l2', alpha=0.01, fit_intercept=True,
loss=loss, n_iter=10, shuffle=True)
clf.fit(X, Y)
# assert_almost_equal(clf.coef_[0], clf.coef_[1], decimal=7)
assert_array_equal(clf.predict(T), true_result)
@raises(ValueError)
def test_sgd_bad_l1_ratio(self):
# Check whether expected ValueError on bad l1_ratio
self.factory(l1_ratio=1.1)
@raises(ValueError)
def test_sgd_bad_learning_rate_schedule(self):
# Check whether expected ValueError on bad learning_rate
self.factory(learning_rate="<unknown>")
@raises(ValueError)
def test_sgd_bad_eta0(self):
# Check whether expected ValueError on bad eta0
self.factory(eta0=0, learning_rate="constant")
@raises(ValueError)
def test_sgd_bad_alpha(self):
# Check whether expected ValueError on bad alpha
self.factory(alpha=-.1)
@raises(ValueError)
def test_sgd_bad_penalty(self):
# Check whether expected ValueError on bad penalty
self.factory(penalty='foobar', l1_ratio=0.85)
@raises(ValueError)
def test_sgd_bad_loss(self):
# Check whether expected ValueError on bad loss
self.factory(loss="foobar")
@raises(ValueError)
def test_sgd_n_iter_param(self):
# Test parameter validity check
self.factory(n_iter=-10000)
@raises(ValueError)
def test_sgd_shuffle_param(self):
# Test parameter validity check
self.factory(shuffle="false")
@raises(TypeError)
def test_argument_coef(self):
# Checks coef_init not allowed as model argument (only fit)
# Provided coef_ does not match dataset.
self.factory(coef_init=np.zeros((3,))).fit(X, Y)
@raises(ValueError)
def test_provide_coef(self):
# Checks coef_init shape for the warm starts
# Provided coef_ does not match dataset.
self.factory().fit(X, Y, coef_init=np.zeros((3,)))
@raises(ValueError)
def test_set_intercept(self):
# Checks intercept_ shape for the warm starts
# Provided intercept_ does not match dataset.
self.factory().fit(X, Y, intercept_init=np.zeros((3,)))
def test_set_intercept_binary(self):
# Checks intercept_ shape for the warm starts in binary case
self.factory().fit(X5, Y5, intercept_init=0)
def test_average_binary_computed_correctly(self):
# Checks the SGDClassifier correctly computes the average weights
eta = .1
alpha = 2.
n_samples = 20
n_features = 10
rng = np.random.RandomState(0)
X = rng.normal(size=(n_samples, n_features))
w = rng.normal(size=n_features)
clf = self.factory(loss='squared_loss',
learning_rate='constant',
eta0=eta, alpha=alpha,
fit_intercept=True,
n_iter=1, average=True, shuffle=False)
# simple linear function without noise
y = np.dot(X, w)
y = np.sign(y)
clf.fit(X, y)
average_weights, average_intercept = self.asgd(X, y, eta, alpha)
average_weights = average_weights.reshape(1, -1)
assert_array_almost_equal(clf.coef_,
average_weights,
decimal=14)
assert_almost_equal(clf.intercept_, average_intercept, decimal=14)
def test_set_intercept_to_intercept(self):
# Checks intercept_ shape consistency for the warm starts
# Inconsistent intercept_ shape.
clf = self.factory().fit(X5, Y5)
self.factory().fit(X5, Y5, intercept_init=clf.intercept_)
clf = self.factory().fit(X, Y)
self.factory().fit(X, Y, intercept_init=clf.intercept_)
@raises(ValueError)
def test_sgd_at_least_two_labels(self):
# Target must have at least two labels
self.factory(alpha=0.01, n_iter=20).fit(X2, np.ones(9))
def test_partial_fit_weight_class_balanced(self):
# partial_fit with class_weight='balanced' not supported"""
assert_raises_regexp(ValueError,
"class_weight 'balanced' is not supported for "
"partial_fit. In order to use 'balanced' weights, "
"use compute_class_weight\('balanced', classes, y\). "
"In place of y you can us a large enough sample "
"of the full training set target to properly "
"estimate the class frequency distributions. "
"Pass the resulting weights as the class_weight "
"parameter.",
self.factory(class_weight='balanced').partial_fit,
X, Y, classes=np.unique(Y))
def test_sgd_multiclass(self):
# Multi-class test case
clf = self.factory(alpha=0.01, n_iter=20).fit(X2, Y2)
assert_equal(clf.coef_.shape, (3, 2))
assert_equal(clf.intercept_.shape, (3,))
assert_equal(clf.decision_function([[0, 0]]).shape, (1, 3))
pred = clf.predict(T2)
assert_array_equal(pred, true_result2)
def test_sgd_multiclass_average(self):
eta = .001
alpha = .01
# Multi-class average test case
clf = self.factory(loss='squared_loss',
learning_rate='constant',
eta0=eta, alpha=alpha,
fit_intercept=True,
n_iter=1, average=True, shuffle=False)
np_Y2 = np.array(Y2)
clf.fit(X2, np_Y2)
classes = np.unique(np_Y2)
for i, cl in enumerate(classes):
y_i = np.ones(np_Y2.shape[0])
y_i[np_Y2 != cl] = -1
average_coef, average_intercept = self.asgd(X2, y_i, eta, alpha)
assert_array_almost_equal(average_coef, clf.coef_[i], decimal=16)
assert_almost_equal(average_intercept,
clf.intercept_[i],
decimal=16)
def test_sgd_multiclass_with_init_coef(self):
# Multi-class test case
clf = self.factory(alpha=0.01, n_iter=20)
clf.fit(X2, Y2, coef_init=np.zeros((3, 2)),
intercept_init=np.zeros(3))
assert_equal(clf.coef_.shape, (3, 2))
assert_true(clf.intercept_.shape, (3,))
pred = clf.predict(T2)
assert_array_equal(pred, true_result2)
def test_sgd_multiclass_njobs(self):
# Multi-class test case with multi-core support
clf = self.factory(alpha=0.01, n_iter=20, n_jobs=2).fit(X2, Y2)
assert_equal(clf.coef_.shape, (3, 2))
assert_equal(clf.intercept_.shape, (3,))
assert_equal(clf.decision_function([[0, 0]]).shape, (1, 3))
pred = clf.predict(T2)
assert_array_equal(pred, true_result2)
def test_set_coef_multiclass(self):
# Checks coef_init and intercept_init shape for for multi-class
# problems
# Provided coef_ does not match dataset
clf = self.factory()
assert_raises(ValueError, clf.fit, X2, Y2, coef_init=np.zeros((2, 2)))
# Provided coef_ does match dataset
clf = self.factory().fit(X2, Y2, coef_init=np.zeros((3, 2)))
# Provided intercept_ does not match dataset
clf = self.factory()
assert_raises(ValueError, clf.fit, X2, Y2,
intercept_init=np.zeros((1,)))
# Provided intercept_ does match dataset.
clf = self.factory().fit(X2, Y2, intercept_init=np.zeros((3,)))
def test_sgd_proba(self):
# Check SGD.predict_proba
# Hinge loss does not allow for conditional prob estimate.
# We cannot use the factory here, because it defines predict_proba
# anyway.
clf = SGDClassifier(loss="hinge", alpha=0.01, n_iter=10).fit(X, Y)
assert_false(hasattr(clf, "predict_proba"))
assert_false(hasattr(clf, "predict_log_proba"))
# log and modified_huber losses can output probability estimates
# binary case
for loss in ["log", "modified_huber"]:
clf = self.factory(loss="modified_huber", alpha=0.01, n_iter=10)
clf.fit(X, Y)
p = clf.predict_proba([[3, 2]])
assert_true(p[0, 1] > 0.5)
p = clf.predict_proba([[-1, -1]])
assert_true(p[0, 1] < 0.5)
p = clf.predict_log_proba([[3, 2]])
assert_true(p[0, 1] > p[0, 0])
p = clf.predict_log_proba([[-1, -1]])
assert_true(p[0, 1] < p[0, 0])
# log loss multiclass probability estimates
clf = self.factory(loss="log", alpha=0.01, n_iter=10).fit(X2, Y2)
d = clf.decision_function([[.1, -.1], [.3, .2]])
p = clf.predict_proba([[.1, -.1], [.3, .2]])
assert_array_equal(np.argmax(p, axis=1), np.argmax(d, axis=1))
assert_almost_equal(p[0].sum(), 1)
assert_true(np.all(p[0] >= 0))
p = clf.predict_proba([[-1, -1]])
d = clf.decision_function([[-1, -1]])
assert_array_equal(np.argsort(p[0]), np.argsort(d[0]))
l = clf.predict_log_proba([[3, 2]])
p = clf.predict_proba([[3, 2]])
assert_array_almost_equal(np.log(p), l)
l = clf.predict_log_proba([[-1, -1]])
p = clf.predict_proba([[-1, -1]])
assert_array_almost_equal(np.log(p), l)
# Modified Huber multiclass probability estimates; requires a separate
# test because the hard zero/one probabilities may destroy the
# ordering present in decision_function output.
clf = self.factory(loss="modified_huber", alpha=0.01, n_iter=10)
clf.fit(X2, Y2)
d = clf.decision_function([[3, 2]])
p = clf.predict_proba([[3, 2]])
if not isinstance(self, SparseSGDClassifierTestCase):
assert_equal(np.argmax(d, axis=1), np.argmax(p, axis=1))
else: # XXX the sparse test gets a different X2 (?)
assert_equal(np.argmin(d, axis=1), np.argmin(p, axis=1))
# the following sample produces decision_function values < -1,
# which would cause naive normalization to fail (see comment
# in SGDClassifier.predict_proba)
x = X.mean(axis=0)
d = clf.decision_function([x])
if np.all(d < -1): # XXX not true in sparse test case (why?)
p = clf.predict_proba([x])
assert_array_almost_equal(p[0], [1 / 3.] * 3)
def test_sgd_l1(self):
# Test L1 regularization
n = len(X4)
rng = np.random.RandomState(13)
idx = np.arange(n)
rng.shuffle(idx)
X = X4[idx, :]
Y = Y4[idx]
clf = self.factory(penalty='l1', alpha=.2, fit_intercept=False,
n_iter=2000, shuffle=False)
clf.fit(X, Y)
assert_array_equal(clf.coef_[0, 1:-1], np.zeros((4,)))
pred = clf.predict(X)
assert_array_equal(pred, Y)
# test sparsify with dense inputs
clf.sparsify()
assert_true(sp.issparse(clf.coef_))
pred = clf.predict(X)
assert_array_equal(pred, Y)
# pickle and unpickle with sparse coef_
clf = pickle.loads(pickle.dumps(clf))
assert_true(sp.issparse(clf.coef_))
pred = clf.predict(X)
assert_array_equal(pred, Y)
def test_class_weights(self):
# Test class weights.
X = np.array([[-1.0, -1.0], [-1.0, 0], [-.8, -1.0],
[1.0, 1.0], [1.0, 0.0]])
y = [1, 1, 1, -1, -1]
clf = self.factory(alpha=0.1, n_iter=1000, fit_intercept=False,
class_weight=None)
clf.fit(X, y)
assert_array_equal(clf.predict([[0.2, -1.0]]), np.array([1]))
# we give a small weights to class 1
clf = self.factory(alpha=0.1, n_iter=1000, fit_intercept=False,
class_weight={1: 0.001})
clf.fit(X, y)
# now the hyperplane should rotate clock-wise and
# the prediction on this point should shift
assert_array_equal(clf.predict([[0.2, -1.0]]), np.array([-1]))
def test_equal_class_weight(self):
# Test if equal class weights approx. equals no class weights.
X = [[1, 0], [1, 0], [0, 1], [0, 1]]
y = [0, 0, 1, 1]
clf = self.factory(alpha=0.1, n_iter=1000, class_weight=None)
clf.fit(X, y)
X = [[1, 0], [0, 1]]
y = [0, 1]
clf_weighted = self.factory(alpha=0.1, n_iter=1000,
class_weight={0: 0.5, 1: 0.5})
clf_weighted.fit(X, y)
# should be similar up to some epsilon due to learning rate schedule
assert_almost_equal(clf.coef_, clf_weighted.coef_, decimal=2)
@raises(ValueError)
def test_wrong_class_weight_label(self):
# ValueError due to not existing class label.
clf = self.factory(alpha=0.1, n_iter=1000, class_weight={0: 0.5})
clf.fit(X, Y)
@raises(ValueError)
def test_wrong_class_weight_format(self):
# ValueError due to wrong class_weight argument type.
clf = self.factory(alpha=0.1, n_iter=1000, class_weight=[0.5])
clf.fit(X, Y)
def test_weights_multiplied(self):
# Tests that class_weight and sample_weight are multiplicative
class_weights = {1: .6, 2: .3}
sample_weights = np.random.random(Y4.shape[0])
multiplied_together = np.copy(sample_weights)
multiplied_together[Y4 == 1] *= class_weights[1]
multiplied_together[Y4 == 2] *= class_weights[2]
clf1 = self.factory(alpha=0.1, n_iter=20, class_weight=class_weights)
clf2 = self.factory(alpha=0.1, n_iter=20)
clf1.fit(X4, Y4, sample_weight=sample_weights)
clf2.fit(X4, Y4, sample_weight=multiplied_together)
assert_almost_equal(clf1.coef_, clf2.coef_)
def test_balanced_weight(self):
# Test class weights for imbalanced data"""
# compute reference metrics on iris dataset that is quite balanced by
# default
X, y = iris.data, iris.target
X = scale(X)
idx = np.arange(X.shape[0])
rng = np.random.RandomState(6)
rng.shuffle(idx)
X = X[idx]
y = y[idx]
clf = self.factory(alpha=0.0001, n_iter=1000,
class_weight=None, shuffle=False).fit(X, y)
assert_almost_equal(metrics.f1_score(y, clf.predict(X), average='weighted'), 0.96,
decimal=1)
# make the same prediction using balanced class_weight
clf_balanced = self.factory(alpha=0.0001, n_iter=1000,
class_weight="balanced",
shuffle=False).fit(X, y)
assert_almost_equal(metrics.f1_score(y, clf_balanced.predict(X), average='weighted'), 0.96,
decimal=1)
# Make sure that in the balanced case it does not change anything
# to use "balanced"
assert_array_almost_equal(clf.coef_, clf_balanced.coef_, 6)
# build an very very imbalanced dataset out of iris data
X_0 = X[y == 0, :]
y_0 = y[y == 0]
X_imbalanced = np.vstack([X] + [X_0] * 10)
y_imbalanced = np.concatenate([y] + [y_0] * 10)
# fit a model on the imbalanced data without class weight info
clf = self.factory(n_iter=1000, class_weight=None, shuffle=False)
clf.fit(X_imbalanced, y_imbalanced)
y_pred = clf.predict(X)
assert_less(metrics.f1_score(y, y_pred, average='weighted'), 0.96)
# fit a model with balanced class_weight enabled
clf = self.factory(n_iter=1000, class_weight="balanced", shuffle=False)
clf.fit(X_imbalanced, y_imbalanced)
y_pred = clf.predict(X)
assert_greater(metrics.f1_score(y, y_pred, average='weighted'), 0.96)
# fit another using a fit parameter override
clf = self.factory(n_iter=1000, class_weight="balanced", shuffle=False)
clf.fit(X_imbalanced, y_imbalanced)
y_pred = clf.predict(X)
assert_greater(metrics.f1_score(y, y_pred, average='weighted'), 0.96)
def test_sample_weights(self):
# Test weights on individual samples
X = np.array([[-1.0, -1.0], [-1.0, 0], [-.8, -1.0],
[1.0, 1.0], [1.0, 0.0]])
y = [1, 1, 1, -1, -1]
clf = self.factory(alpha=0.1, n_iter=1000, fit_intercept=False)
clf.fit(X, y)
assert_array_equal(clf.predict([[0.2, -1.0]]), np.array([1]))
# we give a small weights to class 1
clf.fit(X, y, sample_weight=[0.001] * 3 + [1] * 2)
# now the hyperplane should rotate clock-wise and
# the prediction on this point should shift
assert_array_equal(clf.predict([[0.2, -1.0]]), np.array([-1]))
@raises(ValueError)
def test_wrong_sample_weights(self):
# Test if ValueError is raised if sample_weight has wrong shape
clf = self.factory(alpha=0.1, n_iter=1000, fit_intercept=False)
# provided sample_weight too long
clf.fit(X, Y, sample_weight=np.arange(7))
@raises(ValueError)
def test_partial_fit_exception(self):
clf = self.factory(alpha=0.01)
# classes was not specified
clf.partial_fit(X3, Y3)
def test_partial_fit_binary(self):
third = X.shape[0] // 3
clf = self.factory(alpha=0.01)
classes = np.unique(Y)
clf.partial_fit(X[:third], Y[:third], classes=classes)
assert_equal(clf.coef_.shape, (1, X.shape[1]))
assert_equal(clf.intercept_.shape, (1,))
assert_equal(clf.decision_function([[0, 0]]).shape, (1, ))
id1 = id(clf.coef_.data)
clf.partial_fit(X[third:], Y[third:])
id2 = id(clf.coef_.data)
# check that coef_ haven't been re-allocated
assert_true(id1, id2)
y_pred = clf.predict(T)
assert_array_equal(y_pred, true_result)
def test_partial_fit_multiclass(self):
third = X2.shape[0] // 3
clf = self.factory(alpha=0.01)
classes = np.unique(Y2)
clf.partial_fit(X2[:third], Y2[:third], classes=classes)
assert_equal(clf.coef_.shape, (3, X2.shape[1]))
assert_equal(clf.intercept_.shape, (3,))
assert_equal(clf.decision_function([[0, 0]]).shape, (1, 3))
id1 = id(clf.coef_.data)
clf.partial_fit(X2[third:], Y2[third:])
id2 = id(clf.coef_.data)
# check that coef_ haven't been re-allocated
assert_true(id1, id2)
def test_partial_fit_multiclass_average(self):
third = X2.shape[0] // 3
clf = self.factory(alpha=0.01, average=X2.shape[0])
classes = np.unique(Y2)
clf.partial_fit(X2[:third], Y2[:third], classes=classes)
assert_equal(clf.coef_.shape, (3, X2.shape[1]))
assert_equal(clf.intercept_.shape, (3,))
clf.partial_fit(X2[third:], Y2[third:])
assert_equal(clf.coef_.shape, (3, X2.shape[1]))
assert_equal(clf.intercept_.shape, (3,))
def test_fit_then_partial_fit(self):
# Partial_fit should work after initial fit in the multiclass case.
# Non-regression test for #2496; fit would previously produce a
# Fortran-ordered coef_ that subsequent partial_fit couldn't handle.
clf = self.factory()
clf.fit(X2, Y2)
clf.partial_fit(X2, Y2) # no exception here
def _test_partial_fit_equal_fit(self, lr):
for X_, Y_, T_ in ((X, Y, T), (X2, Y2, T2)):
clf = self.factory(alpha=0.01, eta0=0.01, n_iter=2,
learning_rate=lr, shuffle=False)
clf.fit(X_, Y_)
y_pred = clf.decision_function(T_)
t = clf.t_
classes = np.unique(Y_)
clf = self.factory(alpha=0.01, eta0=0.01, learning_rate=lr,
shuffle=False)
for i in range(2):
clf.partial_fit(X_, Y_, classes=classes)
y_pred2 = clf.decision_function(T_)
assert_equal(clf.t_, t)
assert_array_almost_equal(y_pred, y_pred2, decimal=2)
def test_partial_fit_equal_fit_constant(self):
self._test_partial_fit_equal_fit("constant")
def test_partial_fit_equal_fit_optimal(self):
self._test_partial_fit_equal_fit("optimal")
def test_partial_fit_equal_fit_invscaling(self):
self._test_partial_fit_equal_fit("invscaling")
def test_regression_losses(self):
clf = self.factory(alpha=0.01, learning_rate="constant",
eta0=0.1, loss="epsilon_insensitive")
clf.fit(X, Y)
assert_equal(1.0, np.mean(clf.predict(X) == Y))
clf = self.factory(alpha=0.01, learning_rate="constant",
eta0=0.1, loss="squared_epsilon_insensitive")
clf.fit(X, Y)
assert_equal(1.0, np.mean(clf.predict(X) == Y))
clf = self.factory(alpha=0.01, loss="huber")
clf.fit(X, Y)
assert_equal(1.0, np.mean(clf.predict(X) == Y))
clf = self.factory(alpha=0.01, learning_rate="constant", eta0=0.01,
loss="squared_loss")
clf.fit(X, Y)
assert_equal(1.0, np.mean(clf.predict(X) == Y))
def test_warm_start_multiclass(self):
self._test_warm_start(X2, Y2, "optimal")
def test_multiple_fit(self):
# Test multiple calls of fit w/ different shaped inputs.
clf = self.factory(alpha=0.01, n_iter=5,
shuffle=False)
clf.fit(X, Y)
assert_true(hasattr(clf, "coef_"))
# Non-regression test: try fitting with a different label set.
y = [["ham", "spam"][i] for i in LabelEncoder().fit_transform(Y)]
clf.fit(X[:, :-1], y)
class SparseSGDClassifierTestCase(DenseSGDClassifierTestCase):
"""Run exactly the same tests using the sparse representation variant"""
factory_class = SparseSGDClassifier
###############################################################################
# Regression Test Case
class DenseSGDRegressorTestCase(unittest.TestCase, CommonTest):
"""Test suite for the dense representation variant of SGD"""
factory_class = SGDRegressor
def test_sgd(self):
# Check that SGD gives any results.
clf = self.factory(alpha=0.1, n_iter=2,
fit_intercept=False)
clf.fit([[0, 0], [1, 1], [2, 2]], [0, 1, 2])
assert_equal(clf.coef_[0], clf.coef_[1])
@raises(ValueError)
def test_sgd_bad_penalty(self):
# Check whether expected ValueError on bad penalty
self.factory(penalty='foobar', l1_ratio=0.85)
@raises(ValueError)
def test_sgd_bad_loss(self):
# Check whether expected ValueError on bad loss
self.factory(loss="foobar")
def test_sgd_averaged_computed_correctly(self):
# Tests the average regressor matches the naive implementation
eta = .001
alpha = .01
n_samples = 20
n_features = 10
rng = np.random.RandomState(0)
X = rng.normal(size=(n_samples, n_features))
w = rng.normal(size=n_features)
# simple linear function without noise
y = np.dot(X, w)
clf = self.factory(loss='squared_loss',
learning_rate='constant',
eta0=eta, alpha=alpha,
fit_intercept=True,
n_iter=1, average=True, shuffle=False)
clf.fit(X, y)
average_weights, average_intercept = self.asgd(X, y, eta, alpha)
assert_array_almost_equal(clf.coef_,
average_weights,
decimal=16)
assert_almost_equal(clf.intercept_, average_intercept, decimal=16)
def test_sgd_averaged_partial_fit(self):
# Tests whether the partial fit yields the same average as the fit
eta = .001
alpha = .01
n_samples = 20
n_features = 10
rng = np.random.RandomState(0)
X = rng.normal(size=(n_samples, n_features))
w = rng.normal(size=n_features)
# simple linear function without noise
y = np.dot(X, w)
clf = self.factory(loss='squared_loss',
learning_rate='constant',
eta0=eta, alpha=alpha,
fit_intercept=True,
n_iter=1, average=True, shuffle=False)
clf.partial_fit(X[:int(n_samples / 2)][:], y[:int(n_samples / 2)])
clf.partial_fit(X[int(n_samples / 2):][:], y[int(n_samples / 2):])
average_weights, average_intercept = self.asgd(X, y, eta, alpha)
assert_array_almost_equal(clf.coef_,
average_weights,
decimal=16)
assert_almost_equal(clf.intercept_[0], average_intercept, decimal=16)
def test_average_sparse(self):
# Checks the average weights on data with 0s
eta = .001
alpha = .01
clf = self.factory(loss='squared_loss',
learning_rate='constant',
eta0=eta, alpha=alpha,
fit_intercept=True,
n_iter=1, average=True, shuffle=False)
n_samples = Y3.shape[0]
clf.partial_fit(X3[:int(n_samples / 2)][:], Y3[:int(n_samples / 2)])
clf.partial_fit(X3[int(n_samples / 2):][:], Y3[int(n_samples / 2):])
average_weights, average_intercept = self.asgd(X3, Y3, eta, alpha)
assert_array_almost_equal(clf.coef_,
average_weights,
decimal=16)
assert_almost_equal(clf.intercept_, average_intercept, decimal=16)
def test_sgd_least_squares_fit(self):
xmin, xmax = -5, 5
n_samples = 100
rng = np.random.RandomState(0)
X = np.linspace(xmin, xmax, n_samples).reshape(n_samples, 1)
# simple linear function without noise
y = 0.5 * X.ravel()
clf = self.factory(loss='squared_loss', alpha=0.1, n_iter=20,
fit_intercept=False)
clf.fit(X, y)
score = clf.score(X, y)
assert_greater(score, 0.99)
# simple linear function with noise
y = 0.5 * X.ravel() + rng.randn(n_samples, 1).ravel()
clf = self.factory(loss='squared_loss', alpha=0.1, n_iter=20,
fit_intercept=False)
clf.fit(X, y)
score = clf.score(X, y)
assert_greater(score, 0.5)
def test_sgd_epsilon_insensitive(self):
xmin, xmax = -5, 5
n_samples = 100
X = np.linspace(xmin, xmax, n_samples).reshape(n_samples, 1)
# simple linear function without noise
y = 0.5 * X.ravel()
clf = self.factory(loss='epsilon_insensitive', epsilon=0.01,
alpha=0.1, n_iter=20,
fit_intercept=False)
clf.fit(X, y)
score = clf.score(X, y)
assert_true(score > 0.99)
# simple linear function with noise
y = 0.5 * X.ravel() \
+ np.random.randn(n_samples, 1).ravel()
clf = self.factory(loss='epsilon_insensitive', epsilon=0.01,
alpha=0.1, n_iter=20,
fit_intercept=False)
clf.fit(X, y)
score = clf.score(X, y)
assert_true(score > 0.5)
def test_sgd_huber_fit(self):
xmin, xmax = -5, 5
n_samples = 100
rng = np.random.RandomState(0)
X = np.linspace(xmin, xmax, n_samples).reshape(n_samples, 1)
# simple linear function without noise
y = 0.5 * X.ravel()
clf = self.factory(loss="huber", epsilon=0.1, alpha=0.1, n_iter=20,
fit_intercept=False)
clf.fit(X, y)
score = clf.score(X, y)
assert_greater(score, 0.99)
# simple linear function with noise
y = 0.5 * X.ravel() + rng.randn(n_samples, 1).ravel()
clf = self.factory(loss="huber", epsilon=0.1, alpha=0.1, n_iter=20,
fit_intercept=False)
clf.fit(X, y)
score = clf.score(X, y)
assert_greater(score, 0.5)
def test_elasticnet_convergence(self):
# Check that the SGD output is consistent with coordinate descent
n_samples, n_features = 1000, 5
rng = np.random.RandomState(0)
X = np.random.randn(n_samples, n_features)
# ground_truth linear model that generate y from X and to which the
# models should converge if the regularizer would be set to 0.0
ground_truth_coef = rng.randn(n_features)
y = np.dot(X, ground_truth_coef)
# XXX: alpha = 0.1 seems to cause convergence problems
for alpha in [0.01, 0.001]:
for l1_ratio in [0.5, 0.8, 1.0]:
cd = linear_model.ElasticNet(alpha=alpha, l1_ratio=l1_ratio,
fit_intercept=False)
cd.fit(X, y)
sgd = self.factory(penalty='elasticnet', n_iter=50,
alpha=alpha, l1_ratio=l1_ratio,
fit_intercept=False)
sgd.fit(X, y)
err_msg = ("cd and sgd did not converge to comparable "
"results for alpha=%f and l1_ratio=%f"
% (alpha, l1_ratio))
assert_almost_equal(cd.coef_, sgd.coef_, decimal=2,
err_msg=err_msg)
@ignore_warnings
def test_partial_fit(self):
third = X.shape[0] // 3
clf = self.factory(alpha=0.01)
clf.partial_fit(X[:third], Y[:third])
assert_equal(clf.coef_.shape, (X.shape[1], ))
assert_equal(clf.intercept_.shape, (1,))
assert_equal(clf.predict([[0, 0]]).shape, (1, ))
id1 = id(clf.coef_.data)
clf.partial_fit(X[third:], Y[third:])
id2 = id(clf.coef_.data)
# check that coef_ haven't been re-allocated
assert_true(id1, id2)
def _test_partial_fit_equal_fit(self, lr):
clf = self.factory(alpha=0.01, n_iter=2, eta0=0.01,
learning_rate=lr, shuffle=False)
clf.fit(X, Y)
y_pred = clf.predict(T)
t = clf.t_
clf = self.factory(alpha=0.01, eta0=0.01,
learning_rate=lr, shuffle=False)
for i in range(2):
clf.partial_fit(X, Y)
y_pred2 = clf.predict(T)
assert_equal(clf.t_, t)
assert_array_almost_equal(y_pred, y_pred2, decimal=2)
def test_partial_fit_equal_fit_constant(self):
self._test_partial_fit_equal_fit("constant")
def test_partial_fit_equal_fit_optimal(self):
self._test_partial_fit_equal_fit("optimal")
def test_partial_fit_equal_fit_invscaling(self):
self._test_partial_fit_equal_fit("invscaling")
def test_loss_function_epsilon(self):
clf = self.factory(epsilon=0.9)
clf.set_params(epsilon=0.1)
assert clf.loss_functions['huber'][1] == 0.1
class SparseSGDRegressorTestCase(DenseSGDRegressorTestCase):
# Run exactly the same tests using the sparse representation variant
factory_class = SparseSGDRegressor
def test_l1_ratio():
# Test if l1 ratio extremes match L1 and L2 penalty settings.
X, y = datasets.make_classification(n_samples=1000,
n_features=100, n_informative=20,
random_state=1234)
# test if elasticnet with l1_ratio near 1 gives same result as pure l1
est_en = SGDClassifier(alpha=0.001, penalty='elasticnet',
l1_ratio=0.9999999999, random_state=42).fit(X, y)
est_l1 = SGDClassifier(alpha=0.001, penalty='l1', random_state=42).fit(X, y)
assert_array_almost_equal(est_en.coef_, est_l1.coef_)
# test if elasticnet with l1_ratio near 0 gives same result as pure l2
est_en = SGDClassifier(alpha=0.001, penalty='elasticnet',
l1_ratio=0.0000000001, random_state=42).fit(X, y)
est_l2 = SGDClassifier(alpha=0.001, penalty='l2', random_state=42).fit(X, y)
assert_array_almost_equal(est_en.coef_, est_l2.coef_)
def test_underflow_or_overlow():
with np.errstate(all='raise'):
# Generate some weird data with hugely unscaled features
rng = np.random.RandomState(0)
n_samples = 100
n_features = 10
X = rng.normal(size=(n_samples, n_features))
X[:, :2] *= 1e300
assert_true(np.isfinite(X).all())
# Use MinMaxScaler to scale the data without introducing a numerical
# instability (computing the standard deviation naively is not possible
# on this data)
X_scaled = MinMaxScaler().fit_transform(X)
assert_true(np.isfinite(X_scaled).all())
# Define a ground truth on the scaled data
ground_truth = rng.normal(size=n_features)
y = (np.dot(X_scaled, ground_truth) > 0.).astype(np.int32)
assert_array_equal(np.unique(y), [0, 1])
model = SGDClassifier(alpha=0.1, loss='squared_hinge', n_iter=500)
# smoke test: model is stable on scaled data
model.fit(X_scaled, y)
assert_true(np.isfinite(model.coef_).all())
# model is numerically unstable on unscaled data
msg_regxp = (r"Floating-point under-/overflow occurred at epoch #.*"
" Scaling input data with StandardScaler or MinMaxScaler"
" might help.")
assert_raises_regexp(ValueError, msg_regxp, model.fit, X, y)
def test_numerical_stability_large_gradient():
# Non regression test case for numerical stability on scaled problems
# where the gradient can still explode with some losses
model = SGDClassifier(loss='squared_hinge', n_iter=10, shuffle=True,
penalty='elasticnet', l1_ratio=0.3, alpha=0.01,
eta0=0.001, random_state=0)
with np.errstate(all='raise'):
model.fit(iris.data, iris.target)
assert_true(np.isfinite(model.coef_).all())
def test_large_regularization():
# Non regression tests for numerical stability issues caused by large
# regularization parameters
for penalty in ['l2', 'l1', 'elasticnet']:
model = SGDClassifier(alpha=1e5, learning_rate='constant', eta0=0.1,
n_iter=5, penalty=penalty, shuffle=False)
with np.errstate(all='raise'):
model.fit(iris.data, iris.target)
assert_array_almost_equal(model.coef_, np.zeros_like(model.coef_))
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