def test_kernel_operator_commutative():
# Adding kernels and multiplying kernels should be commutative.
# Check addition
assert_almost_equal((RBF(2.0) + 1.0)(X), (1.0 + RBF(2.0))(X))
# Check multiplication
assert_almost_equal((3.0 * RBF(2.0))(X), (RBF(2.0) * 3.0)(X))
def test_kernel_anisotropic():
# Anisotropic kernel should be consistent with isotropic kernels.
kernel = 3.0 * RBF([0.5, 2.0])
K = kernel(X)
X1 = np.array(X)
X1[:, 0] *= 4
K1 = 3.0 * RBF(2.0)(X1)
assert_almost_equal(K, K1)
X2 = np.array(X)
X2[:, 1] /= 4
K2 = 3.0 * RBF(0.5)(X2)
assert_almost_equal(K, K2)
# Check getting and setting via theta
kernel.theta = kernel.theta + np.log(2)
assert_array_equal(kernel.theta, np.log([6.0, 1.0, 4.0]))
assert_array_equal(kernel.k2.length_scale, [1.0, 4.0])
def test_anisotropic_kernel():
# Test that GPR can identify meaningful anisotropic length-scales.
# We learn a function which varies in one dimension ten-times slower
# than in the other. The corresponding length-scales should differ by at
# least a factor 5
rng = np.random.RandomState(0)
X = rng.uniform(-1, 1, (50, 2))
y = X[:, 0] + 0.1 * X[:, 1]
kernel = RBF([1.0, 1.0])
gpr = GaussianProcessRegressor(kernel=kernel).fit(X, y)
assert (np.exp(gpr.kernel_.theta[1]) > np.exp(gpr.kernel_.theta[0]) * 5)
def test_no_fit_default_predict():
# Test that GPR predictions without fit does not break by default.
default_kernel = (C(1.0, constant_value_bounds="fixed") *
RBF(1.0, length_scale_bounds="fixed"))
gpr1 = GaussianProcessRegressor()
_, y_std1 = gpr1.predict(X, return_std=True)
_, y_cov1 = gpr1.predict(X, return_cov=True)
gpr2 = GaussianProcessRegressor(kernel=default_kernel)
_, y_std2 = gpr2.predict(X, return_std=True)
_, y_cov2 = gpr2.predict(X, return_cov=True)
assert_array_almost_equal(y_std1, y_std2)
assert_array_almost_equal(y_cov1, y_cov2)
def test_y_multioutput():
# Test that GPR can deal with multi-dimensional target values
y_2d = np.vstack((y, y * 2)).T
# Test for fixed kernel that first dimension of 2d GP equals the output
# of 1d GP and that second dimension is twice as large
kernel = RBF(length_scale=1.0)
gpr = GaussianProcessRegressor(kernel=kernel,
optimizer=None,
normalize_y=False)
gpr.fit(X, y)
gpr_2d = GaussianProcessRegressor(kernel=kernel,
optimizer=None,
normalize_y=False)
gpr_2d.fit(X, y_2d)
y_pred_1d, y_std_1d = gpr.predict(X2, return_std=True)
y_pred_2d, y_std_2d = gpr_2d.predict(X2, return_std=True)
_, y_cov_1d = gpr.predict(X2, return_cov=True)
_, y_cov_2d = gpr_2d.predict(X2, return_cov=True)
assert_almost_equal(y_pred_1d, y_pred_2d[:, 0])
assert_almost_equal(y_pred_1d, y_pred_2d[:, 1] / 2)
# Standard deviation and covariance do not depend on output
assert_almost_equal(y_std_1d, y_std_2d)
assert_almost_equal(y_cov_1d, y_cov_2d)
y_sample_1d = gpr.sample_y(X2, n_samples=10)
y_sample_2d = gpr_2d.sample_y(X2, n_samples=10)
assert_almost_equal(y_sample_1d, y_sample_2d[:, 0])
# Test hyperparameter optimization
for kernel in kernels:
gpr = GaussianProcessRegressor(kernel=kernel, normalize_y=True)
gpr.fit(X, y)
gpr_2d = GaussianProcessRegressor(kernel=kernel, normalize_y=True)
gpr_2d.fit(X, np.vstack((y, y)).T)
assert_almost_equal(gpr.kernel_.theta, gpr_2d.kernel_.theta, 4)
def test_random_starts():
# Test that an increasing number of random-starts of GP fitting only
# increases the log marginal likelihood of the chosen theta.
n_samples, n_features = 25, 2
rng = np.random.RandomState(0)
X = rng.randn(n_samples, n_features) * 2 - 1
y = (np.sin(X).sum(axis=1) + np.sin(3 * X).sum(axis=1)) > 0
kernel = C(1.0, (1e-2, 1e2)) \
* RBF(length_scale=[1e-3] * n_features,
length_scale_bounds=[(1e-4, 1e+2)] * n_features)
last_lml = -np.inf
for n_restarts_optimizer in range(5):
gp = GaussianProcessClassifier(
kernel=kernel,
n_restarts_optimizer=n_restarts_optimizer,
random_state=0).fit(X, y)
lml = gp.log_marginal_likelihood(gp.kernel_.theta)
assert lml > last_lml - np.finfo(np.float32).eps
last_lml = lml
def f(x):
return np.sin(x)
X = np.atleast_2d(np.linspace(0, 10, 30)).T
X2 = np.atleast_2d([2., 4., 5.5, 6.5, 7.5]).T
y = np.array(f(X).ravel() > 0, dtype=int)
fX = f(X).ravel()
y_mc = np.empty(y.shape, dtype=int) # multi-class
y_mc[fX < -0.35] = 0
y_mc[(fX >= -0.35) & (fX < 0.35)] = 1
y_mc[fX > 0.35] = 2
fixed_kernel = RBF(length_scale=1.0, length_scale_bounds="fixed")
kernels = [
RBF(length_scale=0.1), fixed_kernel,
RBF(length_scale=1.0, length_scale_bounds=(1e-3, 1e3)),
C(1.0,
(1e-2, 1e2)) * RBF(length_scale=1.0, length_scale_bounds=(1e-3, 1e3))
]
non_fixed_kernels = [kernel for kernel in kernels if kernel != fixed_kernel]
@pytest.mark.parametrize('kernel', kernels)
def test_predict_consistent(kernel):
# Check binary predict decision has also predicted probability above 0.5.
gpc = GaussianProcessClassifier(kernel=kernel).fit(X, y)
assert_array_equal(gpc.predict(X), gpc.predict_proba(X)[:, 1] >= 0.5)
# Authors: Jan Hendrik Metzen <*****@*****.**>
#
# License: BSD 3 clause
import numpy as np
from matplotlib import pyplot as plt
from mrex.gaussian_process import GaussianProcessRegressor
from mrex.gaussian_process.kernels import (RBF, Matern, RationalQuadratic,
ExpSineSquared, DotProduct,
ConstantKernel)
kernels = [1.0 * RBF(length_scale=1.0, length_scale_bounds=(1e-1, 10.0)),
1.0 * RationalQuadratic(length_scale=1.0, alpha=0.1),
1.0 * ExpSineSquared(length_scale=1.0, periodicity=3.0,
length_scale_bounds=(0.1, 10.0),
periodicity_bounds=(1.0, 10.0)),
ConstantKernel(0.1, (0.01, 10.0))
* (DotProduct(sigma_0=1.0, sigma_0_bounds=(0.1, 10.0)) ** 2),
1.0 * Matern(length_scale=1.0, length_scale_bounds=(1e-1, 10.0),
nu=1.5)]
for kernel in kernels:
# Specify Gaussian Process
gp = GaussianProcessRegressor(kernel=kernel)
# Plot prior
plt.figure(figsize=(8, 8))
return x * np.sin(x) # ---------------------------------------------------------------------- # First the noiseless case X = np.atleast_2d([1., 3., 5., 6., 7., 8.]).T # Observations y = f(X).ravel() # Mesh the input space for evaluations of the real function, the prediction and # its MSE x = np.atleast_2d(np.linspace(0, 10, 1000)).T # Instantiate a Gaussian Process model kernel = C(1.0, (1e-3, 1e3)) * RBF(10, (1e-2, 1e2)) gp = GaussianProcessRegressor(kernel=kernel, n_restarts_optimizer=9) # Fit to data using Maximum Likelihood Estimation of the parameters gp.fit(X, y) # Make the prediction on the meshed x-axis (ask for MSE as well) y_pred, sigma = gp.predict(x, return_std=True) # Plot the function, the prediction and the 95% confidence interval based on # the MSE plt.figure() plt.plot(x, f(x), 'r:', label=r'$f(x) = x\,\sin(x)$') plt.plot(X, y, 'r.', markersize=10, label='Observations') plt.plot(x, y_pred, 'b-', label='Prediction') plt.fill(np.concatenate([x, x[::-1]]),
import numpy as np
from matplotlib import pyplot as plt
from mrex.metrics.classification import accuracy_score, log_loss
from mrex.gaussian_process import GaussianProcessClassifier
from mrex.gaussian_process.kernels import RBF
# Generate data
train_size = 50
rng = np.random.RandomState(0)
X = rng.uniform(0, 5, 100)[:, np.newaxis]
y = np.array(X[:, 0] > 2.5, dtype=int)
# Specify Gaussian Processes with fixed and optimized hyperparameters
gp_fix = GaussianProcessClassifier(kernel=1.0 * RBF(length_scale=1.0),
optimizer=None)
gp_fix.fit(X[:train_size], y[:train_size])
gp_opt = GaussianProcessClassifier(kernel=1.0 * RBF(length_scale=1.0))
gp_opt.fit(X[:train_size], y[:train_size])
print("Log Marginal Likelihood (initial): %.3f" %
gp_fix.log_marginal_likelihood(gp_fix.kernel_.theta))
print("Log Marginal Likelihood (optimized): %.3f" %
gp_opt.log_marginal_likelihood(gp_opt.kernel_.theta))
print("Accuracy: %.3f (initial) %.3f (optimized)" %
(accuracy_score(y[:train_size], gp_fix.predict(X[:train_size])),
accuracy_score(y[:train_size], gp_opt.predict(X[:train_size]))))
print("Log-loss: %.3f (initial) %.3f (optimized)" %
import numpy as np
from matplotlib import pyplot as plt
from matplotlib.colors import LogNorm
from mrex.gaussian_process import GaussianProcessRegressor
from mrex.gaussian_process.kernels import RBF, WhiteKernel
rng = np.random.RandomState(0)
X = rng.uniform(0, 5, 20)[:, np.newaxis]
y = 0.5 * np.sin(3 * X[:, 0]) + rng.normal(0, 0.5, X.shape[0])
# First run
plt.figure()
kernel = 1.0 * RBF(length_scale=100.0, length_scale_bounds=(1e-2, 1e3)) \
+ WhiteKernel(noise_level=1, noise_level_bounds=(1e-10, 1e+1))
gp = GaussianProcessRegressor(kernel=kernel, alpha=0.0).fit(X, y)
X_ = np.linspace(0, 5, 100)
y_mean, y_cov = gp.predict(X_[:, np.newaxis], return_cov=True)
plt.plot(X_, y_mean, 'k', lw=3, zorder=9)
plt.fill_between(X_,
y_mean - np.sqrt(np.diag(y_cov)),
y_mean + np.sqrt(np.diag(y_cov)),
alpha=0.5,
color='k')
plt.plot(X_, 0.5 * np.sin(3 * X_), 'r', lw=3, zorder=9)
plt.scatter(X[:, 0], y, c='r', s=50, zorder=10, edgecolors=(0, 0, 0))
plt.title("Initial: %s\nOptimum: %s\nLog-Marginal-Likelihood: %s" %
(kernel, gp.kernel_, gp.log_marginal_likelihood(gp.kernel_.theta)))
plt.tight_layout()
def test_no_optimizer():
# Test that kernel parameters are unmodified when optimizer is None.
kernel = RBF(1.0)
gpr = GaussianProcessRegressor(kernel=kernel, optimizer=None).fit(X, y)
assert np.exp(gpr.kernel_.theta) == 1.0
# License: BSD 3 clause
import numpy as np
import matplotlib.pyplot as plt
from mrex.gaussian_process import GaussianProcessClassifier
from mrex.gaussian_process.kernels import RBF, DotProduct
xx, yy = np.meshgrid(np.linspace(-3, 3, 50), np.linspace(-3, 3, 50))
rng = np.random.RandomState(0)
X = rng.randn(200, 2)
Y = np.logical_xor(X[:, 0] > 0, X[:, 1] > 0)
# fit the model
plt.figure(figsize=(10, 5))
kernels = [1.0 * RBF(length_scale=1.0), 1.0 * DotProduct(sigma_0=1.0)**2]
for i, kernel in enumerate(kernels):
clf = GaussianProcessClassifier(kernel=kernel, warm_start=True).fit(X, Y)
# plot the decision function for each datapoint on the grid
Z = clf.predict_proba(np.vstack((xx.ravel(), yy.ravel())).T)[:, 1]
Z = Z.reshape(xx.shape)
plt.subplot(1, 2, i + 1)
image = plt.imshow(Z,
interpolation='nearest',
extent=(xx.min(), xx.max(), yy.min(), yy.max()),
aspect='auto',
origin='lower',
cmap=plt.cm.PuOr_r)
contours = plt.contour(xx, yy, Z, levels=[0.5], linewidths=2, colors=['k'])
from mrex.naive_bayes import GaussianNB
from mrex.discriminant_analysis import QuadraticDiscriminantAnalysis
h = .02 # step size in the mesh
names = [
"Nearest Neighbors", "Linear SVM", "RBF SVM", "Gaussian Process",
"Decision Tree", "Random Forest", "Neural Net", "AdaBoost", "Naive Bayes",
"QDA"
]
classifiers = [
KNeighborsClassifier(3),
SVC(kernel="linear", C=0.025),
SVC(gamma=2, C=1),
GaussianProcessClassifier(1.0 * RBF(1.0)),
DecisionTreeClassifier(max_depth=5),
RandomForestClassifier(max_depth=5, n_estimators=10, max_features=1),
MLPClassifier(alpha=1, max_iter=1000),
AdaBoostClassifier(),
GaussianNB(),
QuadraticDiscriminantAnalysis()
]
X, y = make_classification(n_features=2,
n_redundant=0,
n_informative=2,
random_state=1,
n_clusters_per_class=1)
rng = np.random.RandomState(2)
X += 2 * rng.uniform(size=X.shape)
from mrex.metrics import accuracy_score
from mrex.linear_model import LogisticRegression
from mrex.svm import SVC
from mrex.gaussian_process import GaussianProcessClassifier
from mrex.gaussian_process.kernels import RBF
from mrex import datasets
iris = datasets.load_iris()
X = iris.data[:, 0:2] # we only take the first two features for visualization
y = iris.target
n_features = X.shape[1]
C = 10
kernel = 1.0 * RBF([1.0, 1.0]) # for GPC
# Create different classifiers.
classifiers = {
'L1 logistic': LogisticRegression(C=C, penalty='l1',
solver='saga',
multi_class='multinomial',
max_iter=10000),
'L2 logistic (Multinomial)': LogisticRegression(C=C, penalty='l2',
solver='saga',
multi_class='multinomial',
max_iter=10000),
'L2 logistic (OvR)': LogisticRegression(C=C, penalty='l2',
solver='saga',
multi_class='ovr',
max_iter=10000),
from mrex.metrics.pairwise \
import PAIRWISE_KERNEL_FUNCTIONS, euclidean_distances, pairwise_kernels
from mrex.gaussian_process.kernels \
import (RBF, Matern, RationalQuadratic, ExpSineSquared, DotProduct,
ConstantKernel, WhiteKernel, PairwiseKernel, KernelOperator,
Exponentiation, Kernel)
from mrex.base import clone
from mrex.utils.testing import (assert_almost_equal, assert_array_equal,
assert_array_almost_equal,
assert_raise_message)
X = np.random.RandomState(0).normal(0, 1, (5, 2))
Y = np.random.RandomState(0).normal(0, 1, (6, 2))
kernel_white = RBF(length_scale=2.0) + WhiteKernel(noise_level=3.0)
kernels = [
RBF(length_scale=2.0),
RBF(length_scale_bounds=(0.5, 2.0)),
ConstantKernel(constant_value=10.0),
2.0 * RBF(length_scale=0.33, length_scale_bounds="fixed"), 2.0 *
RBF(length_scale=0.5), kernel_white, 2.0 * RBF(length_scale=[0.5, 2.0]),
2.0 * Matern(length_scale=0.33, length_scale_bounds="fixed"),
2.0 * Matern(length_scale=0.5, nu=0.5),
2.0 * Matern(length_scale=1.5, nu=1.5),
2.0 * Matern(length_scale=2.5, nu=2.5),
2.0 * Matern(length_scale=[0.5, 2.0], nu=0.5),
3.0 * Matern(length_scale=[2.0, 0.5], nu=1.5),
4.0 * Matern(length_scale=[0.5, 0.5], nu=2.5),
RationalQuadratic(length_scale=0.5, alpha=1.5),
ExpSineSquared(length_scale=0.5, periodicity=1.5),
ppmv_sums.append(ppmv)
counts.append(1)
else:
# aggregate monthly sum to produce average
ppmv_sums[-1] += ppmv
counts[-1] += 1
months = np.asarray(months).reshape(-1, 1)
avg_ppmvs = np.asarray(ppmv_sums) / counts
return months, avg_ppmvs
X, y = load_mauna_loa_atmospheric_co2()
# Kernel with parameters given in GPML book
k1 = 66.0**2 * RBF(length_scale=67.0) # long term smooth rising trend
k2 = 2.4**2 * RBF(length_scale=90.0) \
* ExpSineSquared(length_scale=1.3, periodicity=1.0) # seasonal component
# medium term irregularity
k3 = 0.66**2 \
* RationalQuadratic(length_scale=1.2, alpha=0.78)
k4 = 0.18**2 * RBF(length_scale=0.134) \
+ WhiteKernel(noise_level=0.19**2) # noise terms
kernel_gpml = k1 + k2 + k3 + k4
gp = GaussianProcessRegressor(kernel=kernel_gpml,
alpha=0,
optimizer=None,
normalize_y=True)
gp.fit(X, y)
print(__doc__)
import numpy as np
import matplotlib.pyplot as plt
from mrex import datasets
from mrex.gaussian_process import GaussianProcessClassifier
from mrex.gaussian_process.kernels import RBF
# import some data to play with
iris = datasets.load_iris()
X = iris.data[:, :2] # we only take the first two features.
y = np.array(iris.target, dtype=int)
h = .02 # step size in the mesh
kernel = 1.0 * RBF([1.0])
gpc_rbf_isotropic = GaussianProcessClassifier(kernel=kernel).fit(X, y)
kernel = 1.0 * RBF([1.0, 1.0])
gpc_rbf_anisotropic = GaussianProcessClassifier(kernel=kernel).fit(X, y)
# create a mesh to plot in
x_min, x_max = X[:, 0].min() - 1, X[:, 0].max() + 1
y_min, y_max = X[:, 1].min() - 1, X[:, 1].max() + 1
xx, yy = np.meshgrid(np.arange(x_min, x_max, h), np.arange(y_min, y_max, h))
titles = ["Isotropic RBF", "Anisotropic RBF"]
plt.figure(figsize=(10, 5))
for i, clf in enumerate((gpc_rbf_isotropic, gpc_rbf_anisotropic)):
# Plot the predicted probabilities. For that, we will assign a color to
# each point in the mesh [x_min, m_max]x[y_min, y_max].
plt.subplot(1, 2, i + 1)
