/usr/lib/python3/dist-packages/sklearn/svm/tests/test_svm.py is in python3-sklearn 0.17.0-4.
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Testing for Support Vector Machine module (sklearn.svm)
TODO: remove hard coded numerical results when possible
"""
import numpy as np
import itertools
from numpy.testing import assert_array_equal, assert_array_almost_equal
from numpy.testing import assert_almost_equal
from scipy import sparse
from nose.tools import assert_raises, assert_true, assert_equal, assert_false
from sklearn.base import ChangedBehaviorWarning
from sklearn import svm, linear_model, datasets, metrics, base
from sklearn.cross_validation import train_test_split
from sklearn.datasets import make_classification, make_blobs
from sklearn.metrics import f1_score
from sklearn.metrics.pairwise import rbf_kernel
from sklearn.utils import check_random_state
from sklearn.utils import ConvergenceWarning
from sklearn.utils.validation import NotFittedError
from sklearn.utils.testing import assert_greater, assert_in, assert_less
from sklearn.utils.testing import assert_raises_regexp, assert_warns
from sklearn.utils.testing import assert_warns_message, assert_raise_message
from sklearn.utils.testing import ignore_warnings
from sklearn.multiclass import OneVsRestClassifier
# toy sample
X = [[-2, -1], [-1, -1], [-1, -2], [1, 1], [1, 2], [2, 1]]
Y = [1, 1, 1, 2, 2, 2]
T = [[-1, -1], [2, 2], [3, 2]]
true_result = [1, 2, 2]
# also load the iris dataset
iris = datasets.load_iris()
rng = check_random_state(42)
perm = rng.permutation(iris.target.size)
iris.data = iris.data[perm]
iris.target = iris.target[perm]
def test_libsvm_parameters():
# Test parameters on classes that make use of libsvm.
clf = svm.SVC(kernel='linear').fit(X, Y)
assert_array_equal(clf.dual_coef_, [[-0.25, .25]])
assert_array_equal(clf.support_, [1, 3])
assert_array_equal(clf.support_vectors_, (X[1], X[3]))
assert_array_equal(clf.intercept_, [0.])
assert_array_equal(clf.predict(X), Y)
def test_libsvm_iris():
# Check consistency on dataset iris.
# shuffle the dataset so that labels are not ordered
for k in ('linear', 'rbf'):
clf = svm.SVC(kernel=k).fit(iris.data, iris.target)
assert_greater(np.mean(clf.predict(iris.data) == iris.target), 0.9)
assert_array_equal(clf.classes_, np.sort(clf.classes_))
# check also the low-level API
model = svm.libsvm.fit(iris.data, iris.target.astype(np.float64))
pred = svm.libsvm.predict(iris.data, *model)
assert_greater(np.mean(pred == iris.target), .95)
model = svm.libsvm.fit(iris.data, iris.target.astype(np.float64),
kernel='linear')
pred = svm.libsvm.predict(iris.data, *model, kernel='linear')
assert_greater(np.mean(pred == iris.target), .95)
pred = svm.libsvm.cross_validation(iris.data,
iris.target.astype(np.float64), 5,
kernel='linear',
random_seed=0)
assert_greater(np.mean(pred == iris.target), .95)
# If random_seed >= 0, the libsvm rng is seeded (by calling `srand`), hence
# we should get deteriministic results (assuming that there is no other
# thread calling this wrapper calling `srand` concurrently).
pred2 = svm.libsvm.cross_validation(iris.data,
iris.target.astype(np.float64), 5,
kernel='linear',
random_seed=0)
assert_array_equal(pred, pred2)
@ignore_warnings
def test_single_sample_1d():
# Test whether SVCs work on a single sample given as a 1-d array
clf = svm.SVC().fit(X, Y)
clf.predict(X[0])
clf = svm.LinearSVC(random_state=0).fit(X, Y)
clf.predict(X[0])
def test_precomputed():
# SVC with a precomputed kernel.
# We test it with a toy dataset and with iris.
clf = svm.SVC(kernel='precomputed')
# Gram matrix for train data (square matrix)
# (we use just a linear kernel)
K = np.dot(X, np.array(X).T)
clf.fit(K, Y)
# Gram matrix for test data (rectangular matrix)
KT = np.dot(T, np.array(X).T)
pred = clf.predict(KT)
assert_raises(ValueError, clf.predict, KT.T)
assert_array_equal(clf.dual_coef_, [[-0.25, .25]])
assert_array_equal(clf.support_, [1, 3])
assert_array_equal(clf.intercept_, [0])
assert_array_almost_equal(clf.support_, [1, 3])
assert_array_equal(pred, true_result)
# Gram matrix for test data but compute KT[i,j]
# for support vectors j only.
KT = np.zeros_like(KT)
for i in range(len(T)):
for j in clf.support_:
KT[i, j] = np.dot(T[i], X[j])
pred = clf.predict(KT)
assert_array_equal(pred, true_result)
# same as before, but using a callable function instead of the kernel
# matrix. kernel is just a linear kernel
kfunc = lambda x, y: np.dot(x, y.T)
clf = svm.SVC(kernel=kfunc)
clf.fit(X, Y)
pred = clf.predict(T)
assert_array_equal(clf.dual_coef_, [[-0.25, .25]])
assert_array_equal(clf.intercept_, [0])
assert_array_almost_equal(clf.support_, [1, 3])
assert_array_equal(pred, true_result)
# test a precomputed kernel with the iris dataset
# and check parameters against a linear SVC
clf = svm.SVC(kernel='precomputed')
clf2 = svm.SVC(kernel='linear')
K = np.dot(iris.data, iris.data.T)
clf.fit(K, iris.target)
clf2.fit(iris.data, iris.target)
pred = clf.predict(K)
assert_array_almost_equal(clf.support_, clf2.support_)
assert_array_almost_equal(clf.dual_coef_, clf2.dual_coef_)
assert_array_almost_equal(clf.intercept_, clf2.intercept_)
assert_almost_equal(np.mean(pred == iris.target), .99, decimal=2)
# Gram matrix for test data but compute KT[i,j]
# for support vectors j only.
K = np.zeros_like(K)
for i in range(len(iris.data)):
for j in clf.support_:
K[i, j] = np.dot(iris.data[i], iris.data[j])
pred = clf.predict(K)
assert_almost_equal(np.mean(pred == iris.target), .99, decimal=2)
clf = svm.SVC(kernel=kfunc)
clf.fit(iris.data, iris.target)
assert_almost_equal(np.mean(pred == iris.target), .99, decimal=2)
def test_svr():
# Test Support Vector Regression
diabetes = datasets.load_diabetes()
for clf in (svm.NuSVR(kernel='linear', nu=.4, C=1.0),
svm.NuSVR(kernel='linear', nu=.4, C=10.),
svm.SVR(kernel='linear', C=10.),
svm.LinearSVR(C=10.),
svm.LinearSVR(C=10.),
):
clf.fit(diabetes.data, diabetes.target)
assert_greater(clf.score(diabetes.data, diabetes.target), 0.02)
# non-regression test; previously, BaseLibSVM would check that
# len(np.unique(y)) < 2, which must only be done for SVC
svm.SVR().fit(diabetes.data, np.ones(len(diabetes.data)))
svm.LinearSVR().fit(diabetes.data, np.ones(len(diabetes.data)))
def test_linearsvr():
# check that SVR(kernel='linear') and LinearSVC() give
# comparable results
diabetes = datasets.load_diabetes()
lsvr = svm.LinearSVR(C=1e3).fit(diabetes.data, diabetes.target)
score1 = lsvr.score(diabetes.data, diabetes.target)
svr = svm.SVR(kernel='linear', C=1e3).fit(diabetes.data, diabetes.target)
score2 = svr.score(diabetes.data, diabetes.target)
assert np.linalg.norm(lsvr.coef_ - svr.coef_) / np.linalg.norm(svr.coef_) < .1
assert np.abs(score1 - score2) < 0.1
def test_svr_errors():
X = [[0.0], [1.0]]
y = [0.0, 0.5]
# Bad kernel
clf = svm.SVR(kernel=lambda x, y: np.array([[1.0]]))
clf.fit(X, y)
assert_raises(ValueError, clf.predict, X)
def test_oneclass():
# Test OneClassSVM
clf = svm.OneClassSVM()
clf.fit(X)
pred = clf.predict(T)
assert_array_almost_equal(pred, [-1, -1, -1])
assert_array_almost_equal(clf.intercept_, [-1.008], decimal=3)
assert_array_almost_equal(clf.dual_coef_,
[[0.632, 0.233, 0.633, 0.234, 0.632, 0.633]],
decimal=3)
assert_raises(ValueError, lambda: clf.coef_)
def test_oneclass_decision_function():
# Test OneClassSVM decision function
clf = svm.OneClassSVM()
rnd = check_random_state(2)
# Generate train data
X = 0.3 * rnd.randn(100, 2)
X_train = np.r_[X + 2, X - 2]
# Generate some regular novel observations
X = 0.3 * rnd.randn(20, 2)
X_test = np.r_[X + 2, X - 2]
# Generate some abnormal novel observations
X_outliers = rnd.uniform(low=-4, high=4, size=(20, 2))
# fit the model
clf = svm.OneClassSVM(nu=0.1, kernel="rbf", gamma=0.1)
clf.fit(X_train)
# predict things
y_pred_test = clf.predict(X_test)
assert_greater(np.mean(y_pred_test == 1), .9)
y_pred_outliers = clf.predict(X_outliers)
assert_greater(np.mean(y_pred_outliers == -1), .9)
dec_func_test = clf.decision_function(X_test)
assert_array_equal((dec_func_test > 0).ravel(), y_pred_test == 1)
dec_func_outliers = clf.decision_function(X_outliers)
assert_array_equal((dec_func_outliers > 0).ravel(), y_pred_outliers == 1)
def test_tweak_params():
# Make sure some tweaking of parameters works.
# We change clf.dual_coef_ at run time and expect .predict() to change
# accordingly. Notice that this is not trivial since it involves a lot
# of C/Python copying in the libsvm bindings.
# The success of this test ensures that the mapping between libsvm and
# the python classifier is complete.
clf = svm.SVC(kernel='linear', C=1.0)
clf.fit(X, Y)
assert_array_equal(clf.dual_coef_, [[-.25, .25]])
assert_array_equal(clf.predict([[-.1, -.1]]), [1])
clf._dual_coef_ = np.array([[.0, 1.]])
assert_array_equal(clf.predict([[-.1, -.1]]), [2])
def test_probability():
# Predict probabilities using SVC
# This uses cross validation, so we use a slightly bigger testing set.
for clf in (svm.SVC(probability=True, random_state=0, C=1.0),
svm.NuSVC(probability=True, random_state=0)):
clf.fit(iris.data, iris.target)
prob_predict = clf.predict_proba(iris.data)
assert_array_almost_equal(
np.sum(prob_predict, 1), np.ones(iris.data.shape[0]))
assert_true(np.mean(np.argmax(prob_predict, 1)
== clf.predict(iris.data)) > 0.9)
assert_almost_equal(clf.predict_proba(iris.data),
np.exp(clf.predict_log_proba(iris.data)), 8)
def test_decision_function():
# Test decision_function
# Sanity check, test that decision_function implemented in python
# returns the same as the one in libsvm
# multi class:
clf = svm.SVC(kernel='linear', C=0.1,
decision_function_shape='ovo').fit(iris.data, iris.target)
dec = np.dot(iris.data, clf.coef_.T) + clf.intercept_
assert_array_almost_equal(dec, clf.decision_function(iris.data))
# binary:
clf.fit(X, Y)
dec = np.dot(X, clf.coef_.T) + clf.intercept_
prediction = clf.predict(X)
assert_array_almost_equal(dec.ravel(), clf.decision_function(X))
assert_array_almost_equal(
prediction,
clf.classes_[(clf.decision_function(X) > 0).astype(np.int)])
expected = np.array([-1., -0.66, -1., 0.66, 1., 1.])
assert_array_almost_equal(clf.decision_function(X), expected, 2)
# kernel binary:
clf = svm.SVC(kernel='rbf', gamma=1, decision_function_shape='ovo')
clf.fit(X, Y)
rbfs = rbf_kernel(X, clf.support_vectors_, gamma=clf.gamma)
dec = np.dot(rbfs, clf.dual_coef_.T) + clf.intercept_
assert_array_almost_equal(dec.ravel(), clf.decision_function(X))
def test_decision_function_shape():
# check that decision_function_shape='ovr' gives
# correct shape and is consistent with predict
clf = svm.SVC(kernel='linear', C=0.1,
decision_function_shape='ovr').fit(iris.data, iris.target)
dec = clf.decision_function(iris.data)
assert_equal(dec.shape, (len(iris.data), 3))
assert_array_equal(clf.predict(iris.data), np.argmax(dec, axis=1))
# with five classes:
X, y = make_blobs(n_samples=80, centers=5, random_state=0)
X_train, X_test, y_train, y_test = train_test_split(X, y, random_state=0)
clf = svm.SVC(kernel='linear', C=0.1,
decision_function_shape='ovr').fit(X_train, y_train)
dec = clf.decision_function(X_test)
assert_equal(dec.shape, (len(X_test), 5))
assert_array_equal(clf.predict(X_test), np.argmax(dec, axis=1))
# check shape of ovo_decition_function=True
clf = svm.SVC(kernel='linear', C=0.1,
decision_function_shape='ovo').fit(X_train, y_train)
dec = clf.decision_function(X_train)
assert_equal(dec.shape, (len(X_train), 10))
# check deprecation warning
clf = svm.SVC(kernel='linear', C=0.1).fit(X_train, y_train)
msg = "change the shape of the decision function"
dec = assert_warns_message(ChangedBehaviorWarning, msg,
clf.decision_function, X_train)
assert_equal(dec.shape, (len(X_train), 10))
def test_svr_predict():
# Test SVR's decision_function
# Sanity check, test that predict implemented in python
# returns the same as the one in libsvm
X = iris.data
y = iris.target
# linear kernel
reg = svm.SVR(kernel='linear', C=0.1).fit(X, y)
dec = np.dot(X, reg.coef_.T) + reg.intercept_
assert_array_almost_equal(dec.ravel(), reg.predict(X).ravel())
# rbf kernel
reg = svm.SVR(kernel='rbf', gamma=1).fit(X, y)
rbfs = rbf_kernel(X, reg.support_vectors_, gamma=reg.gamma)
dec = np.dot(rbfs, reg.dual_coef_.T) + reg.intercept_
assert_array_almost_equal(dec.ravel(), reg.predict(X).ravel())
def test_weight():
# Test class weights
clf = svm.SVC(class_weight={1: 0.1})
# we give a small weights to class 1
clf.fit(X, Y)
# so all predicted values belong to class 2
assert_array_almost_equal(clf.predict(X), [2] * 6)
X_, y_ = make_classification(n_samples=200, n_features=10,
weights=[0.833, 0.167], random_state=2)
for clf in (linear_model.LogisticRegression(),
svm.LinearSVC(random_state=0), svm.SVC()):
clf.set_params(class_weight={0: .1, 1: 10})
clf.fit(X_[:100], y_[:100])
y_pred = clf.predict(X_[100:])
assert_true(f1_score(y_[100:], y_pred) > .3)
def test_sample_weights():
# Test weights on individual samples
# TODO: check on NuSVR, OneClass, etc.
clf = svm.SVC()
clf.fit(X, Y)
assert_array_equal(clf.predict([X[2]]), [1.])
sample_weight = [.1] * 3 + [10] * 3
clf.fit(X, Y, sample_weight=sample_weight)
assert_array_equal(clf.predict([X[2]]), [2.])
# test that rescaling all samples is the same as changing C
clf = svm.SVC()
clf.fit(X, Y)
dual_coef_no_weight = clf.dual_coef_
clf.set_params(C=100)
clf.fit(X, Y, sample_weight=np.repeat(0.01, len(X)))
assert_array_almost_equal(dual_coef_no_weight, clf.dual_coef_)
def test_auto_weight():
# Test class weights for imbalanced data
from sklearn.linear_model import LogisticRegression
# We take as dataset the two-dimensional projection of iris so
# that it is not separable and remove half of predictors from
# class 1.
# We add one to the targets as a non-regression test: class_weight="balanced"
# used to work only when the labels where a range [0..K).
from sklearn.utils import compute_class_weight
X, y = iris.data[:, :2], iris.target + 1
unbalanced = np.delete(np.arange(y.size), np.where(y > 2)[0][::2])
classes = np.unique(y[unbalanced])
class_weights = compute_class_weight('balanced', classes, y[unbalanced])
assert_true(np.argmax(class_weights) == 2)
for clf in (svm.SVC(kernel='linear'), svm.LinearSVC(random_state=0),
LogisticRegression()):
# check that score is better when class='balanced' is set.
y_pred = clf.fit(X[unbalanced], y[unbalanced]).predict(X)
clf.set_params(class_weight='balanced')
y_pred_balanced = clf.fit(X[unbalanced], y[unbalanced],).predict(X)
assert_true(metrics.f1_score(y, y_pred, average='weighted')
<= metrics.f1_score(y, y_pred_balanced,
average='weighted'))
def test_bad_input():
# Test that it gives proper exception on deficient input
# impossible value of C
assert_raises(ValueError, svm.SVC(C=-1).fit, X, Y)
# impossible value of nu
clf = svm.NuSVC(nu=0.0)
assert_raises(ValueError, clf.fit, X, Y)
Y2 = Y[:-1] # wrong dimensions for labels
assert_raises(ValueError, clf.fit, X, Y2)
# Test with arrays that are non-contiguous.
for clf in (svm.SVC(), svm.LinearSVC(random_state=0)):
Xf = np.asfortranarray(X)
assert_false(Xf.flags['C_CONTIGUOUS'])
yf = np.ascontiguousarray(np.tile(Y, (2, 1)).T)
yf = yf[:, -1]
assert_false(yf.flags['F_CONTIGUOUS'])
assert_false(yf.flags['C_CONTIGUOUS'])
clf.fit(Xf, yf)
assert_array_equal(clf.predict(T), true_result)
# error for precomputed kernelsx
clf = svm.SVC(kernel='precomputed')
assert_raises(ValueError, clf.fit, X, Y)
# sample_weight bad dimensions
clf = svm.SVC()
assert_raises(ValueError, clf.fit, X, Y, sample_weight=range(len(X) - 1))
# predict with sparse input when trained with dense
clf = svm.SVC().fit(X, Y)
assert_raises(ValueError, clf.predict, sparse.lil_matrix(X))
Xt = np.array(X).T
clf.fit(np.dot(X, Xt), Y)
assert_raises(ValueError, clf.predict, X)
clf = svm.SVC()
clf.fit(X, Y)
assert_raises(ValueError, clf.predict, Xt)
def test_sparse_precomputed():
clf = svm.SVC(kernel='precomputed')
sparse_gram = sparse.csr_matrix([[1, 0], [0, 1]])
try:
clf.fit(sparse_gram, [0, 1])
assert not "reached"
except TypeError as e:
assert_in("Sparse precomputed", str(e))
def test_linearsvc_parameters():
# Test possible parameter combinations in LinearSVC
# Generate list of possible parameter combinations
losses = ['hinge', 'squared_hinge', 'logistic_regression', 'foo']
penalties, duals = ['l1', 'l2', 'bar'], [True, False]
X, y = make_classification(n_samples=5, n_features=5)
for loss, penalty, dual in itertools.product(losses, penalties, duals):
clf = svm.LinearSVC(penalty=penalty, loss=loss, dual=dual)
if ((loss, penalty) == ('hinge', 'l1') or
(loss, penalty, dual) == ('hinge', 'l2', False) or
(penalty, dual) == ('l1', True) or
loss == 'foo' or penalty == 'bar'):
assert_raises_regexp(ValueError,
"Unsupported set of arguments.*penalty='%s.*"
"loss='%s.*dual=%s"
% (penalty, loss, dual),
clf.fit, X, y)
else:
clf.fit(X, y)
# Incorrect loss value - test if explicit error message is raised
assert_raises_regexp(ValueError, ".*loss='l3' is not supported.*",
svm.LinearSVC(loss="l3").fit, X, y)
# FIXME remove in 1.0
def test_linearsvx_loss_penalty_deprecations():
X, y = [[0.0], [1.0]], [0, 1]
msg = ("loss='%s' has been deprecated in favor of "
"loss='%s' as of 0.16. Backward compatibility"
" for the %s will be removed in %s")
# LinearSVC
# loss l1/L1 --> hinge
assert_warns_message(DeprecationWarning,
msg % ("l1", "hinge", "loss='l1'", "1.0"),
svm.LinearSVC(loss="l1").fit, X, y)
# loss l2/L2 --> squared_hinge
assert_warns_message(DeprecationWarning,
msg % ("L2", "squared_hinge", "loss='L2'", "1.0"),
svm.LinearSVC(loss="L2").fit, X, y)
# LinearSVR
# loss l1/L1 --> epsilon_insensitive
assert_warns_message(DeprecationWarning,
msg % ("L1", "epsilon_insensitive", "loss='L1'",
"1.0"),
svm.LinearSVR(loss="L1").fit, X, y)
# loss l2/L2 --> squared_epsilon_insensitive
assert_warns_message(DeprecationWarning,
msg % ("l2", "squared_epsilon_insensitive",
"loss='l2'", "1.0"),
svm.LinearSVR(loss="l2").fit, X, y)
# FIXME remove in 0.18
def test_linear_svx_uppercase_loss_penalty():
# Check if Upper case notation is supported by _fit_liblinear
# which is called by fit
X, y = [[0.0], [1.0]], [0, 1]
msg = ("loss='%s' has been deprecated in favor of "
"loss='%s' as of 0.16. Backward compatibility"
" for the uppercase notation will be removed in %s")
# loss SQUARED_hinge --> squared_hinge
assert_warns_message(DeprecationWarning,
msg % ("SQUARED_hinge", "squared_hinge", "0.18"),
svm.LinearSVC(loss="SQUARED_hinge").fit, X, y)
# penalty L2 --> l2
assert_warns_message(DeprecationWarning,
msg.replace("loss", "penalty")
% ("L2", "l2", "0.18"),
svm.LinearSVC(penalty="L2").fit, X, y)
# loss EPSILON_INSENSITIVE --> epsilon_insensitive
assert_warns_message(DeprecationWarning,
msg % ("EPSILON_INSENSITIVE", "epsilon_insensitive",
"0.18"),
svm.LinearSVR(loss="EPSILON_INSENSITIVE").fit, X, y)
def test_linearsvc():
# Test basic routines using LinearSVC
clf = svm.LinearSVC(random_state=0).fit(X, Y)
# by default should have intercept
assert_true(clf.fit_intercept)
assert_array_equal(clf.predict(T), true_result)
assert_array_almost_equal(clf.intercept_, [0], decimal=3)
# the same with l1 penalty
clf = svm.LinearSVC(penalty='l1', loss='squared_hinge', dual=False, random_state=0).fit(X, Y)
assert_array_equal(clf.predict(T), true_result)
# l2 penalty with dual formulation
clf = svm.LinearSVC(penalty='l2', dual=True, random_state=0).fit(X, Y)
assert_array_equal(clf.predict(T), true_result)
# l2 penalty, l1 loss
clf = svm.LinearSVC(penalty='l2', loss='hinge', dual=True, random_state=0)
clf.fit(X, Y)
assert_array_equal(clf.predict(T), true_result)
# test also decision function
dec = clf.decision_function(T)
res = (dec > 0).astype(np.int) + 1
assert_array_equal(res, true_result)
def test_linearsvc_crammer_singer():
# Test LinearSVC with crammer_singer multi-class svm
ovr_clf = svm.LinearSVC(random_state=0).fit(iris.data, iris.target)
cs_clf = svm.LinearSVC(multi_class='crammer_singer', random_state=0)
cs_clf.fit(iris.data, iris.target)
# similar prediction for ovr and crammer-singer:
assert_true((ovr_clf.predict(iris.data) ==
cs_clf.predict(iris.data)).mean() > .9)
# classifiers shouldn't be the same
assert_true((ovr_clf.coef_ != cs_clf.coef_).all())
# test decision function
assert_array_equal(cs_clf.predict(iris.data),
np.argmax(cs_clf.decision_function(iris.data), axis=1))
dec_func = np.dot(iris.data, cs_clf.coef_.T) + cs_clf.intercept_
assert_array_almost_equal(dec_func, cs_clf.decision_function(iris.data))
def test_crammer_singer_binary():
# Test Crammer-Singer formulation in the binary case
X, y = make_classification(n_classes=2, random_state=0)
for fit_intercept in (True, False):
acc = svm.LinearSVC(fit_intercept=fit_intercept,
multi_class="crammer_singer",
random_state=0).fit(X, y).score(X, y)
assert_greater(acc, 0.9)
def test_linearsvc_iris():
# Test that LinearSVC gives plausible predictions on the iris dataset
# Also, test symbolic class names (classes_).
target = iris.target_names[iris.target]
clf = svm.LinearSVC(random_state=0).fit(iris.data, target)
assert_equal(set(clf.classes_), set(iris.target_names))
assert_greater(np.mean(clf.predict(iris.data) == target), 0.8)
dec = clf.decision_function(iris.data)
pred = iris.target_names[np.argmax(dec, 1)]
assert_array_equal(pred, clf.predict(iris.data))
def test_dense_liblinear_intercept_handling(classifier=svm.LinearSVC):
# Test that dense liblinear honours intercept_scaling param
X = [[2, 1],
[3, 1],
[1, 3],
[2, 3]]
y = [0, 0, 1, 1]
clf = classifier(fit_intercept=True, penalty='l1', loss='squared_hinge',
dual=False, C=4, tol=1e-7, random_state=0)
assert_true(clf.intercept_scaling == 1, clf.intercept_scaling)
assert_true(clf.fit_intercept)
# when intercept_scaling is low the intercept value is highly "penalized"
# by regularization
clf.intercept_scaling = 1
clf.fit(X, y)
assert_almost_equal(clf.intercept_, 0, decimal=5)
# when intercept_scaling is sufficiently high, the intercept value
# is not affected by regularization
clf.intercept_scaling = 100
clf.fit(X, y)
intercept1 = clf.intercept_
assert_less(intercept1, -1)
# when intercept_scaling is sufficiently high, the intercept value
# doesn't depend on intercept_scaling value
clf.intercept_scaling = 1000
clf.fit(X, y)
intercept2 = clf.intercept_
assert_array_almost_equal(intercept1, intercept2, decimal=2)
def test_liblinear_set_coef():
# multi-class case
clf = svm.LinearSVC().fit(iris.data, iris.target)
values = clf.decision_function(iris.data)
clf.coef_ = clf.coef_.copy()
clf.intercept_ = clf.intercept_.copy()
values2 = clf.decision_function(iris.data)
assert_array_almost_equal(values, values2)
# binary-class case
X = [[2, 1],
[3, 1],
[1, 3],
[2, 3]]
y = [0, 0, 1, 1]
clf = svm.LinearSVC().fit(X, y)
values = clf.decision_function(X)
clf.coef_ = clf.coef_.copy()
clf.intercept_ = clf.intercept_.copy()
values2 = clf.decision_function(X)
assert_array_equal(values, values2)
def test_immutable_coef_property():
# Check that primal coef modification are not silently ignored
svms = [
svm.SVC(kernel='linear').fit(iris.data, iris.target),
svm.NuSVC(kernel='linear').fit(iris.data, iris.target),
svm.SVR(kernel='linear').fit(iris.data, iris.target),
svm.NuSVR(kernel='linear').fit(iris.data, iris.target),
svm.OneClassSVM(kernel='linear').fit(iris.data),
]
for clf in svms:
assert_raises(AttributeError, clf.__setattr__, 'coef_', np.arange(3))
assert_raises((RuntimeError, ValueError),
clf.coef_.__setitem__, (0, 0), 0)
def test_linearsvc_verbose():
# stdout: redirect
import os
stdout = os.dup(1) # save original stdout
os.dup2(os.pipe()[1], 1) # replace it
# actual call
clf = svm.LinearSVC(verbose=1)
clf.fit(X, Y)
# stdout: restore
os.dup2(stdout, 1) # restore original stdout
def test_svc_clone_with_callable_kernel():
# create SVM with callable linear kernel, check that results are the same
# as with built-in linear kernel
svm_callable = svm.SVC(kernel=lambda x, y: np.dot(x, y.T),
probability=True, random_state=0,
decision_function_shape='ovr')
# clone for checking clonability with lambda functions..
svm_cloned = base.clone(svm_callable)
svm_cloned.fit(iris.data, iris.target)
svm_builtin = svm.SVC(kernel='linear', probability=True, random_state=0,
decision_function_shape='ovr')
svm_builtin.fit(iris.data, iris.target)
assert_array_almost_equal(svm_cloned.dual_coef_,
svm_builtin.dual_coef_)
assert_array_almost_equal(svm_cloned.intercept_,
svm_builtin.intercept_)
assert_array_equal(svm_cloned.predict(iris.data),
svm_builtin.predict(iris.data))
assert_array_almost_equal(svm_cloned.predict_proba(iris.data),
svm_builtin.predict_proba(iris.data),
decimal=4)
assert_array_almost_equal(svm_cloned.decision_function(iris.data),
svm_builtin.decision_function(iris.data))
def test_svc_bad_kernel():
svc = svm.SVC(kernel=lambda x, y: x)
assert_raises(ValueError, svc.fit, X, Y)
def test_timeout():
a = svm.SVC(kernel=lambda x, y: np.dot(x, y.T), probability=True,
random_state=0, max_iter=1)
assert_warns(ConvergenceWarning, a.fit, X, Y)
def test_unfitted():
X = "foo!" # input validation not required when SVM not fitted
clf = svm.SVC()
assert_raises_regexp(Exception, r".*\bSVC\b.*\bnot\b.*\bfitted\b",
clf.predict, X)
clf = svm.NuSVR()
assert_raises_regexp(Exception, r".*\bNuSVR\b.*\bnot\b.*\bfitted\b",
clf.predict, X)
# ignore convergence warnings from max_iter=1
@ignore_warnings
def test_consistent_proba():
a = svm.SVC(probability=True, max_iter=1, random_state=0)
proba_1 = a.fit(X, Y).predict_proba(X)
a = svm.SVC(probability=True, max_iter=1, random_state=0)
proba_2 = a.fit(X, Y).predict_proba(X)
assert_array_almost_equal(proba_1, proba_2)
def test_linear_svc_convergence_warnings():
# Test that warnings are raised if model does not converge
lsvc = svm.LinearSVC(max_iter=2, verbose=1)
assert_warns(ConvergenceWarning, lsvc.fit, X, Y)
assert_equal(lsvc.n_iter_, 2)
def test_svr_coef_sign():
# Test that SVR(kernel="linear") has coef_ with the right sign.
# Non-regression test for #2933.
X = np.random.RandomState(21).randn(10, 3)
y = np.random.RandomState(12).randn(10)
for svr in [svm.SVR(kernel='linear'), svm.NuSVR(kernel='linear'),
svm.LinearSVR()]:
svr.fit(X, y)
assert_array_almost_equal(svr.predict(X),
np.dot(X, svr.coef_.ravel()) + svr.intercept_)
def test_linear_svc_intercept_scaling():
# Test that the right error message is thrown when intercept_scaling <= 0
for i in [-1, 0]:
lsvc = svm.LinearSVC(intercept_scaling=i)
msg = ('Intercept scaling is %r but needs to be greater than 0.'
' To disable fitting an intercept,'
' set fit_intercept=False.' % lsvc.intercept_scaling)
assert_raise_message(ValueError, msg, lsvc.fit, X, Y)
def test_lsvc_intercept_scaling_zero():
# Test that intercept_scaling is ignored when fit_intercept is False
lsvc = svm.LinearSVC(fit_intercept=False)
lsvc.fit(X, Y)
assert_equal(lsvc.intercept_, 0.)
def test_hasattr_predict_proba():
# Method must be (un)available before or after fit, switched by
# `probability` param
G = svm.SVC(probability=True)
assert_true(hasattr(G, 'predict_proba'))
G.fit(iris.data, iris.target)
assert_true(hasattr(G, 'predict_proba'))
G = svm.SVC(probability=False)
assert_false(hasattr(G, 'predict_proba'))
G.fit(iris.data, iris.target)
assert_false(hasattr(G, 'predict_proba'))
# Switching to `probability=True` after fitting should make
# predict_proba available, but calling it must not work:
G.probability = True
assert_true(hasattr(G, 'predict_proba'))
msg = "predict_proba is not available when fitted with probability=False"
assert_raise_message(NotFittedError, msg, G.predict_proba, iris.data)
def test_decision_function_shape_two_class():
for n_classes in [2, 3]:
X, y = make_blobs(centers=n_classes, random_state=0)
for estimator in [svm.SVC, svm.NuSVC]:
clf = OneVsRestClassifier(estimator(
decision_function_shape="ovr")).fit(X, y)
assert_equal(len(clf.predict(X)), len(y))
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