class KernelExpFiniteGaussianSurrogate(StaticSurrogate):
def __init__(self, ndim, sigma, lmbda, m):
self.surrogate = KernelExpFiniteGaussian(sigma, lmbda, m, D=ndim)
def train(self, samples):
self.surrogate.fit(samples)
def log_pdf_gradient(self, x):
return self.surrogate.grad(x)
def test_KernelExpFiniteGaussian_fit_exactly_m_data_execute():
sigma = 1.
lmbda = 1.
m = 2
N = m
D = 2
est = KernelExpFiniteGaussian(sigma, lmbda, m, D)
X = np.random.randn(N, D)
est.fit(X)
def get_KernelAdaptiveLangevin_instance(D, target_log_pdf):
step_size = 1.
m = 500
surrogate = KernelExpFiniteGaussian(sigma=10, lmbda=1., m=m, D=D)
logger.info("kernel exp family uses %s" % surrogate.get_parameters())
instance = KernelAdaptiveLangevin(D, target_log_pdf, surrogate, step_size)
return instance
def test_KernelExpFiniteGaussian_fit_less_than_m_data_execute():
sigma = 1.
lmbda = 1.
m = 20
N = 10
D = 2
est = KernelExpFiniteGaussian(sigma, lmbda, m, D)
X = np.random.randn(N, D)
est.fit(X)
def get_OracleKernelAdaptiveLangevin_instance(D, target_log_pdf):
step_size = 1.
m = 500
N = 5000
Z = sample_banana(N, D, bananicity, V)
surrogate = KernelExpFiniteGaussian(sigma=10, lmbda=.001, m=m, D=D)
surrogate.fit(Z)
if False:
param_bounds = {'sigma': [-2, 3]}
bo = BayesOptSearch(surrogate, Z, param_bounds)
best_params = bo.optimize()
surrogate.set_parameters_from_dict(best_params)
if False:
sigma = 1. / gamma_median_heuristic(Z)
surrogate.set_parameters_from_dict({'sigma': sigma})
logger.info("kernel exp family uses %s" % surrogate.get_parameters())
if False:
import matplotlib.pyplot as plt
Xs = np.linspace(-30, 30, 50)
Ys = np.linspace(-20, 40, 50)
visualise_fit_2d(surrogate, Z, Xs, Ys)
plt.show()
instance = OracleKernelAdaptiveLangevin(D, target_log_pdf, surrogate,
step_size)
return instance
def get_KernelAdaptiveLangevin_instance(D, target_log_pdf):
step_size = 1.
m = 500
surrogate = KernelExpFiniteGaussian(sigma=10, lmbda=1., m=m, D=D)
logger.info("kernel exp family uses %s" % surrogate.get_parameters())
instance = KernelAdaptiveLangevin(D, target_log_pdf, surrogate,
step_size)
return instance
def get_OracleKernelAdaptiveLangevin_instance(D, target_log_pdf):
step_size = 1.
m = 500
N = 5000
Z = sample_banana(N, D, bananicity, V)
surrogate = KernelExpFiniteGaussian(sigma=10, lmbda=.001, m=m, D=D)
surrogate.fit(Z)
if False:
param_bounds = {'sigma': [-2, 3]}
bo = BayesOptSearch(surrogate, Z, param_bounds)
best_params = bo.optimize()
surrogate.set_parameters_from_dict(best_params)
if False:
sigma = 1. / gamma_median_heuristic(Z)
surrogate.set_parameters_from_dict({'sigma': sigma})
logger.info("kernel exp family uses %s" % surrogate.get_parameters())
if False:
import matplotlib.pyplot as plt
Xs = np.linspace(-30, 30, 50)
Ys = np.linspace(-20, 40, 50)
visualise_fit_2d(surrogate, Z, Xs, Ys)
plt.show()
instance = OracleKernelAdaptiveLangevin(D, target_log_pdf, surrogate, step_size)
return instance
def test_KernelExpFiniteGaussian_fit_equals_update_fit():
sigma = 1.
lmbda = 2.
m = 2
N = 1
D = 2
rng_state = np.random.get_state()
np.random.seed(0)
est_batch = KernelExpFiniteGaussian(sigma, lmbda, m, D)
np.random.seed(0)
est_update = KernelExpFiniteGaussian(sigma, lmbda, m, D)
np.random.set_state(rng_state)
assert_equal(est_batch.b, None)
assert_equal(est_update.b, None)
assert_equal(est_batch.L_C, None)
assert_allclose(est_batch.n, est_update.n)
assert_allclose(est_batch.theta, np.zeros(m))
assert_allclose(est_update.theta, np.zeros(m))
X = np.random.randn(N, D)
est_batch.fit(X)
est_update.update_fit(X)
assert_allclose(est_batch.b, est_update.b)
assert_allclose(est_batch.L_C, est_update.L_C)
assert_allclose(est_batch.n, est_update.n)
assert_allclose(est_batch.theta, est_update.theta)
def get_OracleKernelAdaptiveLangevin_instance(D, target_log_pdf, grad):
step_size = 1.
schedule = one_over_sqrt_t_schedule
acc_star = 0.574
N = 500
m = 500
Z = sample_banana(N=N, D=D, bananicity=0.03, V=100)
surrogate = KernelExpFiniteGaussian(sigma=10, lmbda=1., m=m, D=D)
surrogate.fit(Z)
instance = OracleKernelAdaptiveLangevin(D, target_log_pdf, surrogate, step_size, schedule, acc_star)
return instance
def get_KernelAdaptiveLangevin_instance(D, target_log_pdf, grad):
step_size = 1.
schedule = one_over_sqrt_t_schedule
acc_star = 0.574
m = 500
surrogate = KernelExpFiniteGaussian(sigma=10, lmbda=1., m=m, D=D)
instance = KernelAdaptiveLangevin(D, target_log_pdf, surrogate, step_size, schedule, acc_star)
return instance
def get_OracleKernelAdaptiveLangevin_instance(D, target_log_pdf):
step_size = 0.002
m = 1000
sigma = 0.7
lmbda = 1.
surrogate = KernelExpFiniteGaussian(sigma=sigma, lmbda=lmbda, m=m, D=D)
logger.info("Fitting kernel exp family in batch mode")
instance = OracleKernelAdaptiveLangevin(D, target_log_pdf, surrogate,
step_size)
instance.set_batch(benchmark_samples)
return instance
def get_KernelAdaptiveLangevin_instance(D, target_log_pdf):
step_size = 0.002
m = 1000
sigma = 0.7
lmbda = 1.
surrogate = KernelExpFiniteGaussian(sigma=sigma, lmbda=lmbda, m=m, D=D)
instance = KernelAdaptiveLangevin(D, target_log_pdf, surrogate,
step_size)
# feed a small number of pilot samples into algorithm
instance.set_batch(benchmark_samples[:num_initial_oracle])
return instance
def test_hessian_execute():
if not theano_available:
raise SkipTest("Theano not available.")
sigma = 1.
lmbda = 1.
N = 100
D = 2
m = 10
X = np.random.randn(N, D)
est = KernelExpFiniteGaussian(sigma, lmbda, m, D)
est.fit(X)
est.hessian(X[0])
def test_third_order_derivative_tensor_execute():
if not theano_available:
raise SkipTest("Theano not available.")
sigma = 1.
lmbda = 1.
N = 100
D = 2
m = 10
X = np.random.randn(N, D)
est = KernelExpFiniteGaussian(sigma, lmbda, m, D)
est.fit(X)
est.third_order_derivative_tensor(X[0])
# run MCMC
samples, proposals, accepted, acc_prob, log_pdf, times, step_sizes = mini_mcmc(
kmc, start, num_iter, D)
visualise_trace(samples,
log_pdf,
accepted,
log_pdf_density=surrogate,
step_sizes=step_sizes)
plt.suptitle("KMC lite %s, acceptance rate: %.2f" % \
(surrogate.__class__.__name__, np.mean(accepted)))
# now initialise KMC finite with the samples from the surrogate, and run for more
# learn parameters before starting
thinned = samples[np.random.permutation(len(samples))[:N]]
surrogate2 = KernelExpFiniteGaussian(sigma=2, lmbda=0.001, D=D, m=N)
surrogate2.set_parameters_from_dict(
BayesOptSearch(surrogate2, thinned, {
'sigma': [-3, 3]
}).optimize(3))
surrogate2.fit(thinned)
# now use conservative schedule, or None at all if confident in oracle samples
schedule2 = lambda t: 0.01 if t < 3000 else 0.
kmc2 = KMC(surrogate2, target, momentum, kmc.num_steps_min,
kmc.num_steps_max, kmc.step_size[0], kmc.step_size[1],
schedule2, acc_star)
# run MCMC
samples2, proposals2, accepted2, acc_prob2, log_pdf2, times2, step_sizes = mini_mcmc(
kmc2, start, num_iter, D)
# possible to change
# for D=2, the fitted log-density is plotted, otherwise trajectory only
D = 2
N = 1000
# target is banana density, fallback to Gaussian if theano is not present
if banana_available:
target = Banana(D=D)
X = sample_banana(N, D)
else:
target = IsotropicZeroMeanGaussian(D=D)
X = sample_gaussian(N=N)
# plot trajectories for both KMC lite and finite, parameters are chosen for D=2
for surrogate in [
KernelExpFiniteGaussian(sigma=2, lmbda=0.001, m=N, D=D),
KernelExpLiteGaussian(sigma=20., lmbda=0.001, D=D, N=N),
KernelExpLiteGaussianLowRank(sigma=20,
lmbda=0.1,
D=D,
N=N,
cg_tol=0.01),
]:
# try uncommenting this line to illustrate KMC's ability to mix even
# when no (or incomplete) samples from the target are available
surrogate.fit(X)
# HMC parameters, fixed here, use oracle mean variance to set momentum
momentum = IsotropicZeroMeanGaussian(D=D,
sigma=np.sqrt(
np.mean(np.var(X, 0))))
N_fit = 50000
ms_fit = np.array([1, 2, 5, 10, 25, 50, 75, 100, 250, 500, 1000, 2000, 5000])
sigma = 1
lmbda = 0.01
grad = lambda x: est.grad(np.array([x]))[0]
s = GaussianQuadraticTest(grad)
num_bootstrap = 200
result_fname = os.path.splitext(os.path.basename(__file__))[0] + ".txt"
num_repetitions = 150
for _ in range(num_repetitions):
for m in ms_fit:
est = KernelExpFiniteGaussian(sigma, lmbda, m, D)
X_test = np.random.randn(N_test, D)
X = np.random.randn(N_fit, D)
est.fit(X)
U_matrix, stat = s.get_statistic_multiple(X_test[:,0])
bootsraped_stats = np.empty(num_bootstrap)
for i in range(num_bootstrap):
W = np.sign(np.random.randn(N_test))
WW = np.outer(W, W)
st = np.mean(U_matrix * WW)
bootsraped_stats[i] = N_test * st
p_value = np.mean(bootsraped_stats>stat)
m = 1000
lmbda = 1.
res = 10
log2_sigmas = np.linspace(-4, 10, res)
log2_sigmas = np.log2([0.5, 0.7, 0.9, 1.1, 1.3, 1.5])
print "log2_sigmas:", log2_sigmas
print "sigmas:", 2 ** log2_sigmas
Js_mean = np.zeros(res)
Js_var = np.zeros(res)
for i, log2_sigma in enumerate(log2_sigmas):
sigma = 2 ** log2_sigma
surrogate = KernelExpFiniteGaussian(sigma=sigma, lmbda=lmbda, m=m, D=benchmark_samples.shape[1])
vals = surrogate.xvalidate_objective(benchmark_samples)
Js_mean[i] = np.mean(vals)
Js_var[i] = np.var(vals)
print "log2_sigma: %.3f, sigma: %.3f, mean: %.3f, var: %.3f" % (log2_sigma, sigma, Js_mean[i], Js_var[i])
surrogate = KernelExpFiniteGaussian(sigma=sigma, lmbda=lmbda, m=m, D=benchmark_samples.shape[1])
surrogate.fit(benchmark_samples)
fake = empty_class()
def replace_2(x_2d, a, i, j):
a = a.copy()
a[i] = x_2d[0]
a[j] = x_2d[1]
return a
def get_instace_KernelExpFiniteGaussian(N):
sigma = 2.
lmbda = 2.
D = 2
m = 2
return KernelExpFiniteGaussian(sigma, lmbda, m, D)
m = 1000
lmbda = 1.
res = 10
log2_sigmas = np.linspace(-4, 10, res)
log2_sigmas = np.log2([0.5, 0.7, 0.9, 1.1, 1.3, 1.5])
print "log2_sigmas:", log2_sigmas
print "sigmas:", 2**log2_sigmas
Js_mean = np.zeros(res)
Js_var = np.zeros(res)
for i, log2_sigma in enumerate(log2_sigmas):
sigma = 2**log2_sigma
surrogate = KernelExpFiniteGaussian(sigma=sigma,
lmbda=lmbda,
m=m,
D=benchmark_samples.shape[1])
vals = surrogate.xvalidate_objective(benchmark_samples)
Js_mean[i] = np.mean(vals)
Js_var[i] = np.var(vals)
print "log2_sigma: %.3f, sigma: %.3f, mean: %.3f, var: %.3f" % (
log2_sigma, sigma, Js_mean[i], Js_var[i])
surrogate = KernelExpFiniteGaussian(sigma=sigma,
lmbda=lmbda,
m=m,
D=benchmark_samples.shape[1])
surrogate.fit(benchmark_samples)
fake = empty_class()
def replace_2(x_2d, a, i, j):
Then, increasing amounts of "correct" data are added and the fits are
visualised.
"""
N = 50
D = 2
# fit model to samples from a wrong Gaussian, to see updates later
X = np.random.randn(N, D) * 10
# arbitrary choice of parameters here
# note that m is set to N in order to call update_fit immediately,
# as throws an error if called with less data
sigma = 2
lmbda = 1.
m = N
est = KernelExpFiniteGaussian(sigma, lmbda, m, D)
# only for plotting
all_data = []
# plotting grid
width = 6
Xs = np.linspace(-width, width, 50)
Ys = np.linspace(-width, width, 50)
# plot ground truth
plt.figure(figsize=(10, 10))
fig_count = 1
plt.subplot(3, 3, fig_count)
_, G_true = pdf_grid(Xs, Ys, ground_truth())
visualise_array(Xs, Ys, G_true)
def get_KernelExpFiniteGaussian_instance(D):
# arbitrary choice of parameters here
sigma = 2
lmbda = 1
m = 100
return KernelExpFiniteGaussian(sigma, lmbda, m, D)
def __init__(self, ndim, sigma, lmbda, m):
self.surrogate = KernelExpFiniteGaussian(sigma, lmbda, m, D=ndim)
This simple demo demonstrates how to select the kernel parameter for the lite
estimator, based on a Bayesian optimisation black-box optimiser.
Note that this optimiser can be "hot-started", i.e. it can be reset, but using
the previous model as initialiser for the new optimisation, which is useful
when the objective function changes slightly, e.g. when a new data was added
to the kernel exponential family model.
"""
N = 200
D = 2
# fit model to samples from a standard Gaussian
X = np.random.randn(N, D)
# use any of the below models, might have to change parameter bounds
estimators = [
KernelExpFiniteGaussian(sigma=1., lmbda=1., m=N, D=D),
KernelExpLiteGaussian(sigma=1., lmbda=.001, D=D, N=N),
]
for est in estimators:
print(est.__class__.__name__)
est.fit(X)
# specify bounds of parameters to search for
param_bounds = {
# 'lmbda': [-5,0], # fixed lmbda, uncomment to include in search
'sigma': [-2, 3],
}
# oop interface for optimising and using results
# set to around 5000-10000 iterations to have KMC lite explored all of the support
start = np.zeros(D)
start[1] = -3
num_iter = 500
# run MCMC
samples, proposals, accepted, acc_prob, log_pdf, times, step_sizes = mini_mcmc(kmc, start, num_iter, D)
visualise_trace(samples, log_pdf, accepted, log_pdf_density=surrogate, step_sizes=step_sizes)
plt.suptitle("KMC lite %s, acceptance rate: %.2f" % \
(surrogate.__class__.__name__, np.mean(accepted)))
# now initialise KMC finite with the samples from the surrogate, and run for more
# learn parameters before starting
thinned = samples[np.random.permutation(len(samples))[:N]]
surrogate2 = KernelExpFiniteGaussian(sigma=2, lmbda=0.001, D=D, m=N)
surrogate2.set_parameters_from_dict(BayesOptSearch(surrogate2, thinned, {'sigma': [-3,3]}).optimize(3))
surrogate2.fit(thinned)
# now use conservative schedule, or None at all if confident in oracle samples
schedule2 = lambda t: 0.01 if t < 3000 else 0.
kmc2 = KMC(surrogate2, target,
momentum, kmc.num_steps_min, kmc.num_steps_max, kmc.step_size[0], kmc.step_size[1],
schedule2, acc_star)
# run MCMC
samples2, proposals2, accepted2, acc_prob2, log_pdf2, times2, step_sizes = mini_mcmc(kmc2, start, num_iter, D)
visualise_trace(samples2, log_pdf2, accepted2, log_pdf_density=surrogate2, step_sizes=step_sizes)
plt.suptitle("KMC finite, %s, acceptance rate: %.2f" % \
(surrogate.__class__.__name__, np.mean(accepted2)))
plt.show()
