def test_obs(x):
prior = Measure()
f = GP(EQ(), measure=prior)
noise = 0.1
# Generate some data.
w = B.rand(B.shape(x)[0]) + 1e-2
y = f(x, 0.1).sample()
# Set some observations to be missing.
y_missing = y.copy()
y_missing[::2] = np.nan
# Check dense case.
gpar = GPAR()
obs = gpar._obs(x, None, y_missing, w, f, noise)
assert isinstance(obs, Obs)
approx(
prior.logpdf(obs),
f(x[1::2], noise / w[1::2]).logpdf(y[1::2]),
atol=1e-6,
)
# Check sparse case.
gpar = GPAR(x_ind=x)
obs = gpar._obs(x, x, y_missing, w, f, noise)
assert isinstance(obs, SparseObs)
approx(
prior.logpdf(obs),
f(x[1::2], noise / w[1::2]).logpdf(y[1::2]),
atol=1e-6,
)
def test_combine():
x1 = B.linspace(0, 2, 10)
x2 = B.linspace(2, 4, 10)
m = Measure()
p1 = GP(EQ(), measure=m)
p2 = GP(Matern12(), measure=m)
y1 = p1(x1).sample()
y2 = p2(x2).sample()
# Check the one-argument case.
assert_equal_normals(combine(p1(x1, 1)), p1(x1, 1))
fdd_combined, y_combined = combine((p1(x1, 1), B.squeeze(y1)))
assert_equal_normals(fdd_combined, p1(x1, 1))
approx(y_combined, y1)
# Check the two-argument case.
fdd_combined = combine(p1(x1, 1), p2(x2, 2))
assert_equal_normals(
fdd_combined,
Normal(B.block_diag(p1(x1, 1).var,
p2(x2, 2).var)),
)
fdd_combined, y_combined = combine((p1(x1, 1), B.squeeze(y1)),
(p2(x2, 2), y2))
assert_equal_normals(
fdd_combined,
Normal(B.block_diag(p1(x1, 1).var,
p2(x2, 2).var)),
)
approx(y_combined, B.concat(y1, y2, axis=0))
def test_logpdf(x, w):
prior = Measure()
f1, noise1 = GP(EQ(), measure=prior), 2e-1
f2, noise2 = GP(Linear(), measure=prior), 1e-1
gpar = GPAR().add_layer(lambda: (f1, noise1)).add_layer(lambda: (f2, noise2))
# Generate some data.
y = gpar.sample(x, w, latent=True)
# Compute logpdf.
x1 = x
x2 = B.concat(x, y[:, 0:1], axis=1)
logpdf1 = f1(x1, noise1 / w[:, 0]).logpdf(y[:, 0])
logpdf2 = f2(x2, noise2 / w[:, 1]).logpdf(y[:, 1])
# Test computation of GPAR.
assert gpar.logpdf(x, y, w) == logpdf1 + logpdf2
assert gpar.logpdf(x, y, w, only_last_layer=True) == logpdf2
# Test resuming computation.
x_partial, x_ind_partial = gpar.logpdf(x, y, w, return_inputs=True, outputs=[0])
assert gpar.logpdf(x_partial, y, w, x_ind=x_ind_partial, outputs=[1]) == logpdf2
# Test that sampling missing gives a stochastic estimate.
y[1, 0] = np.nan
all_different(
gpar.logpdf(x, y, w, sample_missing=True),
gpar.logpdf(x, y, w, sample_missing=True),
)
def test_dimensionality():
m = Measure()
p1 = GP(EQ(), measure=m)
p2 = GP(2 * EQ().stretch(2), measure=m)
k1 = MultiOutputKernel(m, p1, p2)
k2 = MultiOutputKernel(m, p1, p1)
assert dimensionality(EQ()) == 1
assert dimensionality(k1) == 2
# Test the unpacking of `Wrapped`s and `Join`s.
assert dimensionality(k1 + k2) == 2
assert dimensionality(k1 * k2) == 2
assert dimensionality(k1.periodic(1)) == 2
assert dimensionality(k1.stretch(2)) == 2
# Check that dimensionalities must line up.
with pytest.raises(RuntimeError):
dimensionality(k1 + EQ())
# Check `PosteriorKernel`.
assert dimensionality(PosteriorKernel(EQ(), EQ(), EQ(), None, 0)) == 1
assert dimensionality(PosteriorKernel(k1, k2, k2, None, 0)) == 2
assert dimensionality(PosteriorKernel(k1, k2, ADK(EQ()), None, 0)) == 2
with pytest.raises(RuntimeError):
assert dimensionality(PosteriorKernel(k1, k2, EQ(), None, 0)) == 2
# Check `SubspaceKernel`.
assert dimensionality(SubspaceKernel(EQ(), EQ(), None, 0)) == 1
assert dimensionality(SubspaceKernel(k1, k2, None, 0)) == 2
assert dimensionality(SubspaceKernel(k1, ADK(EQ()), None, 0)) == 2
with pytest.raises(RuntimeError):
assert dimensionality(SubspaceKernel(k1, EQ(), None, 0)) == 2
def test_conditioning(x, w):
prior = Measure()
f1, e1 = GP(EQ(), measure=prior), GP(1e-10 * Delta(), measure=prior)
f2, e2 = GP(EQ(), measure=prior), GP(2e-10 * Delta(), measure=prior)
gpar = GPAR().add_layer(lambda: (f1, e1)).add_layer(lambda: (f2, e2))
# Generate some data.
y = B.concat((f1 + e1)(x).sample(), (f2 + e2)(x).sample(), axis=1)
# Extract posterior processes.
gpar = gpar | (x, y, w)
f1_post, e1_post = gpar.layers[0]()
f2_post, e2_post = gpar.layers[1]()
# Test independence of noises.
assert f1_post.measure.kernels[f1_post, e1_post] == ZeroKernel()
assert f2_post.measure.kernels[f2_post, e2_post] == ZeroKernel()
# Test form of noises.
assert e1.mean == e1_post.mean
assert e1.kernel == e1_post.kernel
assert e2.mean == e2_post.mean
assert e2.kernel == e2_post.kernel
# Test posteriors.
approx(f1_post.mean(x), y[:, 0:1], atol=1e-3)
approx(f2_post.mean(B.concat(x, y[:, 0:1], axis=1)), y[:, 1:2], atol=1e-3)
def test_logpdf(x, w):
prior = Measure()
f1, e1 = GP(EQ(), measure=prior), GP(2e-1 * Delta(), measure=prior)
f2, e2 = GP(Linear(), measure=prior), GP(1e-1 * Delta(), measure=prior)
gpar = GPAR().add_layer(lambda: (f1, e1)).add_layer(lambda: (f2, e2))
# Generate some data.
y = gpar.sample(x, w, latent=True)
# Compute logpdf.
x1 = WeightedUnique(x, w[:, 0])
x2 = WeightedUnique(B.concat(x, y[:, 0:1], axis=1), w[:, 1])
logpdf1 = (f1 + e1)(x1).logpdf(y[:, 0])
logpdf2 = (f2 + e2)(x2).logpdf(y[:, 1])
# Test computation of GPAR.
assert gpar.logpdf(x, y, w) == logpdf1 + logpdf2
assert gpar.logpdf(x, y, w, only_last_layer=True) == logpdf2
# Test resuming computation.
x_partial, x_ind_partial = gpar.logpdf(x,
y,
w,
return_inputs=True,
outputs=[0])
assert gpar.logpdf(x_partial, y, w, x_ind=x_ind_partial,
outputs=[1]) == logpdf2
# Test that sampling missing gives a stochastic estimate.
y[1, 0] = np.nan
all_different(
gpar.logpdf(x, y, w, sample_missing=True),
gpar.logpdf(x, y, w, sample_missing=True),
)
def test_sample(x, w):
prior = Measure()
# Test that it produces random samples.
f1, noise1 = GP(EQ(), measure=prior), 1e-1
f2, noise2 = GP(EQ(), measure=prior), 2e-1
gpar = GPAR().add_layer(lambda: (f1, noise1)).add_layer(lambda: (f2, noise2))
all_different(gpar.sample(x, w), gpar.sample(x, w))
all_different(gpar.sample(x, w, latent=True), gpar.sample(x, w, latent=True))
# Test that posterior latent samples are around the data that is conditioned on.
prior = Measure()
f1, noise1 = GP(EQ(), measure=prior), 1e-10
f2, noise2 = GP(EQ(), measure=prior), 2e-10
gpar = GPAR().add_layer(lambda: (f1, noise1)).add_layer(lambda: (f2, noise2))
y = gpar.sample(x, w, latent=True)
gpar = gpar | (x, y, w)
approx(gpar.sample(x, w), y, atol=1e-3)
approx(gpar.sample(x, w, latent=True), y, atol=1e-3)
def test_infer_size():
x = B.linspace(0, 2, 5)
m = Measure()
p1 = GP(EQ(), measure=m)
p2 = GP(2 * EQ().stretch(2), measure=m)
k = MultiOutputKernel(m, p1, p2)
assert infer_size(k, x) == 10
assert infer_size(k, p1(x)) == 5
assert infer_size(k, (x, p1(x))) == 15
def __init__(
self,
kernels: List[Kernel],
h: AbstractMatrix,
noise_obs: B.Numeric,
noises_latent: B.Numeric,
):
measure = Measure()
# Create latent processes.
xs = [GP(k, measure=measure) for k in kernels]
ILMMPP.__init__(self, measure, xs, h, noise_obs, noises_latent)
def test_infer_size():
x = B.linspace(0, 2, 5)
m = Measure()
p1 = GP(EQ(), measure=m)
p2 = GP(2 * EQ().stretch(2), measure=m)
k = MultiOutputKernel(m, p1, p2)
assert infer_size(k, x) == 10
assert infer_size(k, p1(x)) == 5
assert infer_size(k, (x, p1(x))) == 15
# Check that the dimensionality must be inferrable.
assert infer_size(EQ(), x) == 5
with pytest.raises(RuntimeError):
infer_size(ADK(EQ()), x)
def test_dimensionality():
m = Measure()
p1 = GP(EQ(), measure=m)
p2 = GP(2 * EQ().stretch(2), measure=m)
k1 = MultiOutputKernel(m, p1, p2)
k2 = MultiOutputKernel(m, p1, p1)
assert dimensionality(EQ()) == 1
assert dimensionality(k1) == 2
# Test the unpacking of `Wrapped`s and `Join`s.
assert dimensionality(k1 + k2) == 2
assert dimensionality(k1 * k2) == 2
assert dimensionality(k1.periodic(1)) == 2
assert dimensionality(k1.stretch(2)) == 2
# Test consistency check.
with pytest.raises(RuntimeError):
dimensionality(k1 + EQ())
def test_conditioning(x, w):
prior = Measure()
f1, noise1 = GP(EQ(), measure=prior), 1e-10
f2, noise2 = GP(EQ(), measure=prior), 2e-10
gpar = GPAR().add_layer(lambda: (f1, noise1)).add_layer(lambda: (f2, noise2))
# Generate some data.
y = B.concat(f1(x, noise1).sample(), f2(x, noise2).sample(), axis=1)
# Extract posterior processes.
gpar = gpar | (x, y, w)
f1_post, noise1_post = gpar.layers[0]()
f2_post, noise2_post = gpar.layers[1]()
# Test noises.
assert noise1 == noise1_post
assert noise2 == noise2_post
# Test posteriors.
approx(f1_post.mean(x), y[:, 0:1], atol=1e-3)
approx(f2_post.mean(B.concat(x, y[:, 0:1], axis=1)), y[:, 1:2], atol=1e-3)
def test_fdd_take():
with Measure():
f1 = GP(1, EQ())
f2 = GP(2, Exp())
f = cross(f1, f2)
x = B.linspace(0, 3, 5)
# Build an FDD with a very complicated input specification.
fdd = f((x, (f2(x), x), f1(x), (f2(x), (f1(x), x))))
n = infer_size(fdd.p.kernel, fdd.x)
fdd = f(fdd.x, matrix.Diagonal(B.rand(n)))
# Flip a coin for every element.
mask = B.randn(n) > 0
taken_fdd = B.take(fdd, mask)
approx(taken_fdd.mean, B.take(fdd.mean, mask))
approx(taken_fdd.var, B.submatrix(fdd.var, mask))
approx(taken_fdd.noise, B.submatrix(fdd.noise, mask))
assert isinstance(taken_fdd.noise, matrix.Diagonal)
# Test that only masks are supported, for now.
with pytest.raises(AssertionError):
B.take(fdd, np.array([1, 2]))
def test_update_inputs():
prior = Measure()
f = GP(EQ(), measure=prior)
x = np.array([[1], [2], [3]])
y = np.array([[4], [5], [6]], dtype=float)
res = B.concat(x, y, axis=1)
x_ind = np.array([[6], [7]])
res_ind = np.array([[6, 0], [7, 0]])
# Check vanilla case.
gpar = GPAR(x_ind=x_ind)
approx(gpar._update_inputs(x, x_ind, y, f, None), (res, res_ind))
# Check imputation with prior.
gpar = GPAR(impute=True, x_ind=x_ind)
this_y = y.copy()
this_y[1] = np.nan
this_res = res.copy()
this_res[1, 1] = 0
approx(gpar._update_inputs(x, x_ind, this_y, f, None), (this_res, res_ind))
# Check replacing with prior.
gpar = GPAR(replace=True, x_ind=x_ind)
this_y = y.copy()
this_y[1] = np.nan
this_res = res.copy()
this_res[0, 1] = 0
this_res[1, 1] = np.nan
this_res[2, 1] = 0
approx(gpar._update_inputs(x, x_ind, this_y, f, None), (this_res, res_ind))
# Check imputation and replacing with prior.
gpar = GPAR(impute=True, replace=True, x_ind=x_ind)
this_res = res.copy()
this_res[:, 1] = 0
approx(gpar._update_inputs(x, x_ind, y, f, None), (this_res, res_ind))
# Construct observations and update result for inducing points.
obs = Obs(f(np.array([1, 2, 3, 6, 7])), np.array([9, 10, 11, 12, 13]))
res_ind = np.array([[6, 12], [7, 13]])
# Check imputation with posterior.
gpar = GPAR(impute=True, x_ind=x_ind)
this_y = y.copy()
this_y[1] = np.nan
this_res = res.copy()
this_res[1, 1] = 10
approx(gpar._update_inputs(x, x_ind, this_y, f, obs), (this_res, res_ind))
# Check replacing with posterior.
gpar = GPAR(replace=True, x_ind=x_ind)
this_y = y.copy()
this_y[1] = np.nan
this_res = res.copy()
this_res[0, 1] = 9
this_res[1, 1] = np.nan
this_res[2, 1] = 11
approx(gpar._update_inputs(x, x_ind, this_y, f, obs), (this_res, res_ind))
# Check imputation and replacing with posterior.
gpar = GPAR(impute=True, replace=True, x_ind=x_ind)
this_res = res.copy()
this_res[0, 1] = 9
this_res[1, 1] = 10
this_res[2, 1] = 11
approx(gpar._update_inputs(x, x_ind, y, f, obs), (this_res, res_ind))
import matplotlib.pyplot as plt from wbml.plot import tweak from stheno import B, Measure, GP, EQ # Define points to predict at. x = B.linspace(0, 10, 100) # Construct a prior. prior = Measure() f1 = GP(3, EQ(), measure=prior) f2 = GP(3, EQ(), measure=prior) # Compute the approximate product. f_prod = f1 * f2 # Sample two functions. s1, s2 = prior.sample(f1(x), f2(x)) # Predict. post = prior | ((f1(x), s1), (f2(x), s2)) mean, lower, upper = post(f_prod(x)).marginals() # Plot result. plt.plot(x, s1, label="Sample 1", style="train") plt.plot(x, s2, label="Sample 2", style="train", ls="--") plt.plot(x, s1 * s2, label="True product", style="test") plt.plot(x, mean, label="Approximate posterior", style="pred") plt.fill_between(x, lower, upper, style="pred") tweak()
for j in range(n):
ps[i] += A[i, j] * self.ps[j]
return VGP(ps)
# Define points to predict at.
x = B.linspace(0, 10, 100)
x_obs = B.linspace(0, 10, 10)
# Model parameters:
m = 2
p = 4
H = B.randn(p, m)
# Construct latent functions.
prior = Measure()
us = VGP([GP(EQ(), measure=prior) for _ in range(m)])
fs = us.lmatmul(H)
# Construct noise.
e = VGP([GP(0.5 * Delta(), measure=prior) for _ in range(p)])
# Construct observation model.
ys = e + fs
# Sample a true, underlying function and observations.
samples = prior.sample(*(p(x) for p in fs.ps), *(p(x_obs) for p in ys.ps))
fs_true, ys_obs = samples[:p], samples[p:]
# Compute the posterior and make predictions.
post = prior | (*((p(x_obs), y_obs) for p, y_obs in zip(ys.ps, ys_obs)), )
# Setup experiment.
n = 881 # Add last one for `linspace`.
noise = 0.1
t = B.linspace(-44, 44, n)
t_plot = B.linspace(44, 44, 500)
# Setup true model and GPCM models.
kernel = EQ()
window = 2
scale = 1
n_u = 40
n_z = 88
# Sample data.
m = Measure()
gp_f = GP(kernel, measure=m)
gp_y = gp_f + GP(noise * Delta(), measure=m)
truth, y = map(B.flatten, m.sample(gp_f(t_plot), gp_y(t)))
# Remove region [-8.8, 8.8].
inds = ~((t >= -8.8) & (t <= 8.8))
t = t[inds]
y = y[inds]
def comparative_kernel(vs_):
return vs_.pos(1) * kernel.stretch(vs_.pos(1.0)) + vs_.pos(noise) * Delta()
run(
import matplotlib.pyplot as plt from wbml.plot import tweak from stheno import Measure, GP, EQ, RQ, Linear, Delta, Exp, B B.epsilon = 1e-10 # Define points to predict at. x = B.linspace(0, 10, 200) x_obs = B.linspace(0, 7, 50) # Construct a latent function consisting of four different components. prior = Measure() f_smooth = GP(EQ(), measure=prior) f_wiggly = GP(RQ(1e-1).stretch(0.5), measure=prior) f_periodic = GP(EQ().periodic(1.0), measure=prior) f_linear = GP(Linear(), measure=prior) f = f_smooth + f_wiggly + f_periodic + 0.2 * f_linear # Let the observation noise consist of a bit of exponential noise. e_indep = GP(Delta(), measure=prior) e_exp = GP(Exp(), measure=prior) e = e_indep + 0.3 * e_exp # Sum the latent function and observation noise to get a model for the observations. y = f + 0.5 * e # Sample a true, underlying function and observations. (
import matplotlib.pyplot as plt
from wbml.plot import tweak
from stheno import Measure, GP, EQ, RQ, Linear, Delta, Exp, B
B.epsilon = 1e-10
# Define points to predict at.
x = B.linspace(0, 10, 200)
x_obs = B.linspace(0, 7, 50)
with Measure() as prior:
# Construct a latent function consisting of four different components.
f_smooth = GP(EQ())
f_wiggly = GP(RQ(1e-1).stretch(0.5))
f_periodic = GP(EQ().periodic(1.0))
f_linear = GP(Linear())
f = f_smooth + f_wiggly + f_periodic + 0.2 * f_linear
# Let the observation noise consist of a bit of exponential noise.
e_indep = GP(Delta())
e_exp = GP(Exp())
e = e_indep + 0.3 * e_exp
# Sum the latent function and observation noise to get a model for the observations.
y = f + 0.5 * e
# Sample a true, underlying function and observations.
(
f_true_smooth,
f_true_wiggly,
import matplotlib.pyplot as plt
from wbml.plot import tweak
from stheno import B, Measure, GP, EQ, Delta
# Define points to predict at.
x = B.linspace(0, 10, 100)
x_obs = B.linspace(0, 10, 20)
# Constuct a prior:
prior = Measure()
w = lambda x: B.exp(-(x**2) / 0.5) # Window
b = [(w * GP(EQ(), measure=prior)).shift(xi)
for xi in x_obs] # Weighted basis funs
f = sum(b) # Latent function
e = GP(Delta(), measure=prior) # Noise
y = f + 0.2 * e # Observation model
# Sample a true, underlying function and observations.
f_true, y_obs = prior.sample(f(x), y(x_obs))
# Condition on the observations to make predictions.
post = prior | (y(x_obs), y_obs)
# Plot result.
for i, bi in enumerate(b):
mean, lower, upper = post(bi(x)).marginals()
kw_args = {"label": "Basis functions"} if i == 0 else {}
plt.plot(x, mean, style="pred2", **kw_args)
plt.plot(x, f_true, label="True", style="test")
plt.scatter(x_obs, y_obs, label="Observations", style="train", s=20)
import matplotlib.pyplot as plt
import wbml.out as out
from wbml.plot import tweak
from stheno import B, Measure, GP, Delta
# Define points to predict at.
x = B.linspace(0, 10, 200)
x_obs = B.linspace(0, 10, 10)
# Construct the model.
prior = Measure()
slope = GP(1, measure=prior)
intercept = GP(5, measure=prior)
f = slope * (lambda x: x) + intercept
e = 0.2 * GP(Delta(), measure=prior) # Noise model
y = f + e # Observation model
# Sample a slope, intercept, underlying function, and observations.
true_slope, true_intercept, f_true, y_obs = prior.sample(
slope(0), intercept(0), f(x), y(x_obs))
# Condition on the observations to make predictions.
post = prior | (y(x_obs), y_obs)
mean, lower, upper = post(f(x)).marginals()
out.kv("True slope", true_slope[0, 0])
out.kv("Predicted slope", post(slope(0)).mean[0, 0])
out.kv("True intercept", true_intercept[0, 0])
