def quadrature(self):
budget = self.options['budget']
phis = np.empty((budget, 1))
rs = np.empty((budget, ))
rqs = np.empty((budget, ))
phi_init = self.p.mean.reshape(1, 1)
r_init = self.r.sample(phi_init)
kern = GPy.kern.RBF(input_dim=1, variance=1., lengthscale=1.)
rq_init = r_init * self.q.sample(phi_init)
r_gp = GPy.models.GPRegression(phi_init,
np.sqrt(2 * r_init).reshape(1, 1), kern)
rq_gp = GPy.models.GPRegression(phi_init,
np.sqrt(2 * rq_init).reshape(1, 1),
kern)
r_model = WarpedIntegrandModel(WsabiLGP(r_gp), self.p)
rq_model = WarpedIntegrandModel(WsabiLGP(rq_gp), self.p)
phis[0, :] = phi_init
rs[0] = r_init
rqs[0] = rq_init
for i in range(1, budget):
phi = (select_batch(r_model,
1)[0]).reshape(1, 1) # phi is 1 dimensional!
phis[i, :] = phi
rs[i] = self.r.sample(phi)
rqs[i] = rs[i] * self.q.sample(phi)
r_model.update(phi, rs[i].reshape(1, 1))
rq_model.update(phi, rqs[i].reshape(1, 1))
r_gp.optimize()
rq_gp.optimize()
rq_int_mean = rq_model.integral_mean()[0]
r_int_mean = r_model.integral_mean()[0]
self.results[i] = rq_int_mean / r_int_mean
if i % 10 == 1:
print('Samples', phi, "Numerator: ", rq_int_mean,
"Denominator", r_int_mean)
if self.options['plot_iterations']:
self.draw_samples(i, phis, rs, rqs, r_model, rq_model)
plt.show()
return self.results[-1]
def quadrature(self):
from bayesquad.quadrature import compute_mean_gp_prod_gpy_2
budget = self.options['budget']
phis = np.empty((budget, 1))
rs = np.empty((budget, ))
qs = np.empty((budget, ))
phi_init = self.p.mean.reshape(1, 1)
r_init = np.array(self.r.sample(phi_init))
q_init = np.array(self.q.sample(phi_init))
kern = GPy.kern.RBF(input_dim=1, variance=1., lengthscale=1.)
r_gp = GPy.models.GPRegression(phi_init,
np.sqrt(2 * r_init).reshape(1, 1), kern)
q_gp = GPy.models.GPRegression(phi_init,
np.sqrt(2 * q_init).reshape(1, 1), kern)
r_model = WarpedIntegrandModel(WsabiLGP(r_gp), self.p)
q_model = WarpedIntegrandModel(WsabiLGP(q_gp), self.p)
phis[0, :] = phi_init
rs[0] = r_init
qs[0] = q_init
for i in range(1, budget):
phi = select_batch(r_model, 1)[0].reshape(1, 1)
r = self.r.sample(phi)
q = self.q.sample(phi)
r_model.update(phi, r.reshape(1, 1))
q_model.update(phi, q.reshape(1, 1))
r_gp.optimize()
q_gp.optimize()
rs[i] = r
qs[i] = q
phis[i, :] = phi
rq_gp = GPy.models.GPRegression(
phis[:i + 1, :], q_model.gp._gp.Y * r_model.gp._gp.Y, kern)
rq_gp.optimize()
alpha_q = q_model.gp._alpha
alpha_r = r_model.gp._alpha
r_int_mean = r_model.integral_mean()[0]
n1 = alpha_r * alpha_q
n2 = 0.5 * alpha_r * compute_mean_gp_prod_gpy_2(
self.p, q_model.gp._gp, q_model.gp._gp)
n3 = 0.5 * alpha_q * compute_mean_gp_prod_gpy_2(
self.p, r_model.gp._gp, r_model.gp._gp)
n4 = 0.25 * (compute_mean_gp_prod_gpy_2(self.p, rq_gp, rq_gp))
rq_int_mean = n1 + n2 + n3 + n4
self.results[i] = rq_int_mean / r_int_mean
if i % self.options['display_step'] == 0:
print('Samples', phi, "Numerator: ", rq_int_mean,
"Denominator", r_int_mean)
return self.results[-1]
def wsabi(self, verbose=True):
# Allocating number of maximum evaluations
start = time.time()
budget = self.options['wsabi_budget']
batch_count = 1
test_x = self.model.X_test
test_y = np.squeeze(self.model.Y_test)
# Allocate memory of the samples and results
log_phi = np.zeros((
budget * batch_count,
self.dimensions,
)) # The log-hyperparameter sampling points
log_r = np.zeros(
(budget * batch_count, )) # The log-likelihood function
q = np.zeros((test_x.shape[0], budget * batch_count)) # Prediction
# Set prior mean to the MAP value
# log_phi_initial = np.zeros(self.dimensions).reshape(1, -1)
log_phi_initial = self.options['prior_mean'].reshape(1, -1)
log_r_initial = np.sqrt(2 * np.exp(
self.model.log_sample(phi=np.exp(log_phi_initial).reshape(-1))[0]))
# print(log_r_initial)
pred = np.zeros((test_x.shape[0], ))
# Setting up kernel - Note we only marginalise over the lengthscale terms, other hyperparameters are set to the
# MAP values.
kern = GPy.kern.RBF(
self.dimensions,
variance=.1, #0.1
lengthscale=.1) #0.1
log_r_gp = GPy.models.GPRegression(log_phi_initial,
log_r_initial.reshape(1, -1), kern)
log_r_model = WarpedIntegrandModel(WsabiLGP(log_r_gp), self.prior)
# Firstly, within the given allowance, compute an estimate of the model evidence. Model evidence is the common
# denominator for all predictive distributions.
for i_a in range(budget):
log_phi_i = np.array(
select_batch(log_r_model, batch_count,
"Kriging Believer")).reshape(batch_count, -1)
log_r_i = self.model.log_sample(phi=np.exp(log_phi_i))[0]
if verbose:
logging.info('phi: ' + str(log_phi_i) + ' log_lik: ' +
str(log_r_i))
log_r[i_a:i_a + batch_count] = log_r_i
log_phi[i_a:i_a + batch_count, :] = log_phi_i
log_r_model.update(log_phi_i, np.exp(log_r_i).reshape(1, -1))
quad_time = time.time()
max_log_r = max(log_r)
r = np.exp(log_r - max_log_r)
r_gp = GPy.models.GPRegression(log_phi[:1, :],
np.sqrt(2 * r[0].reshape(1, 1)), kern)
r_model = WarpedIntegrandModel(WsabiLGP(r_gp), self.prior)
r_model.update(log_phi[1:, :], r[1:].reshape(-1, 1))
r_gp.optimize()
r_int = np.exp(np.log(r_model.integral_mean()[0]) +
max_log_r) # Model evidence
log_r_int = np.log(r_int) # Model log-evidence
print(
"Estimate of model evidence: ",
r_int,
)
print("Model log-evidence ", log_r_int)
# Secondly, compute and marginalise the predictive distribution for each individual points
for i_x in range(test_x.shape[0]):
# Note that we do not active sample again for q, we just use the same samples sampled when we compute
# the log-evidence
_, q_initial = self.model.log_sample(phi=np.exp(log_phi_initial),
x=test_x[i_x, :])
# Initialise GPy GP surrogate for and q(\phi)r(\phi)
# Sample for q values
for i_b in range(budget * batch_count):
log_phi_i = log_phi[i_b, :]
log_r_i, q_i = self.model.log_sample(phi=np.exp(log_phi_i),
x=test_x[i_x, :])
q[i_x, i_b] = q_i
# Enforce positivity in q
q_x = q[i_x, :]
q_min = np.min(q_x)
if q_min < 0:
q_x = q_x - q_min
else:
q_min = 0
# Do the same exponentiation and rescaling trick for q
log_rq_x = log_r + np.log(q_x)
max_log_rq = np.max(log_rq_x)
rq = np.exp(log_rq_x - max_log_rq)
rq_gp = GPy.models.GPRegression(log_phi[:1, :],
np.sqrt(2 * rq[0].reshape(1, 1)),
kern)
rq_model = WarpedIntegrandModel(WsabiLGP(rq_gp), self.prior)
rq_model.update(log_phi[1:, :], rq[1:].reshape(-1, 1))
rq_gp.optimize()
# Now estimate the posterior
# rq_int = rq_model.integral_mean()[0] + q_min * r_int
rq_int = np.exp(np.log(rq_model.integral_mean()[0]) +
max_log_rq) + q_min * r_int
# Similar for variance
pred[i_x] = rq_int / r_int
logging.info('Progress: ' + str(i_x + 1) + '/' +
str(test_x.shape[0]))
if verbose:
logging.info('Prediction' + str(pred[i_x]) + ' .Label: ' +
str(test_y[i_x]))
labels = pred.copy()
labels[labels < 0.5] = 0
labels[labels >= 0.5] = 1
labels = np.squeeze(labels)
accuracy, precision, recall, f1 = self.model.score(
np.squeeze(test_y), labels)
non_zero = np.count_nonzero(np.squeeze(test_y) - np.squeeze(labels))
print("------ WSABI Summary -----------")
print("Number of mismatch: " + str(non_zero))
print("Accuracy: " + str(accuracy))
print("Precision: " + str(precision))
print("Recall: " + str(recall))
print("F1 score: " + str(f1))
if verbose:
print("Ground truth labels: " + str(test_y))
print("Predictions: " + str(labels))
print('Predictive Probabilities: ' + str(pred))
end = time.time()
print("Active Sampling Time: ", quad_time - start)
print("Total Time: ", end - start)
# Save the results
labels = labels.reshape(-1)
pred = pred.reshape(-1)
test_y = test_y.reshape(-1)
res = np.vstack([labels, pred, test_y]).T
res = pd.DataFrame(res, columns=['pred', 'pred_prob', 'labels'])
res.to_csv('svm_wsabi.csv')
return accuracy, precision, recall, f1
def plotting_callback(func):
z = np.exp(func(PLOTTING_DOMAIN, calculate_jacobian=False)[0])
plot_data(z, 131, "Acquisition Function")
plotting.add_callback("Soft penalised log acquisition function",
plotting_callback)
plot_true_function()
# Run algorithm.
BATCHES = 25
BATCH_SIZE = 4
for i in range(BATCHES):
plot_integrand_posterior(model)
batch = select_batch(model, BATCH_SIZE, LOCAL_PENALISATION)
X = np.array(batch)
Y = true_function(X)
model.update(X, Y)
gpy_gp.optimize()
print("Integral: {}".format(model.integral_mean()))
plot_integrand_posterior(model)
plt.show()
def wsabi_bqr(self, verbose=True, compute_var=True):
from bayesquad.quadrature import compute_mean_gp_prod_gpy_2
# Allocating number of maximum evaluations
start = time.time()
budget = self.options['wsabi_budget']
test_x = self.gpr.X_test
test_y = self.gpr.Y_test
# Allocate memory of the samples and results
log_phi = np.zeros((
budget,
self.dimensions,
)) # The log-hyperparameter sampling points
log_r = np.zeros((budget, )) # The log-likelihood function
q = np.zeros((test_x.shape[0], budget)) # Prediction
var = np.zeros((test_x.shape[0], budget)) # Posterior variance
# Initial points - note that as per GPML convention, the hyperparameters are expressed in log scale
# Initialise to the MAP estimate
map_model, _, _ = self.maximum_a_posterior(num_restarts=1,
max_iters=1000,
verbose=False)
if isinstance(self.gpr, PeriodicGPRegression):
self.gpr.set_params(
variance=map_model.std_periodic.variance,
gaussian_noise=map_model.Gaussian_noise.variance)
elif isinstance(self.gpr, RBFGPRegression):
self.gpr.set_params(
variance=map_model.rbf.variance,
gaussian_noise=map_model.Gaussian_noise.variance)
# Set prior mean to the MAP value
# self.prior = Gaussian(mean=map_vals.reshape(-1), covariance=self.options['prior_variance'])
log_phi_initial = self.options['prior_mean'].reshape(1, -1)
log_r_initial = np.sqrt(2 * np.exp(
self.gpr.log_sample(phi=np.exp(log_phi_initial.reshape(-1)))[0]))
pred = np.zeros((test_x.shape[0], ))
pred_var = np.zeros((test_x.shape[0], ))
# Setting up kernel - Note we only marginalise over the lengthscale terms, other hyperparameters are set to the
# MAP values.
kern = GPy.kern.RBF(self.dimensions, variance=1., lengthscale=1.)
log_r_gp = GPy.models.GPRegression(log_phi_initial,
log_r_initial.reshape(1, -1), kern)
log_r_model = WarpedIntegrandModel(WsabiLGP(log_r_gp), self.prior)
# Firstly, within the given allowance, compute an estimate of the model evidence. Model evidence is the common
# denominator for all predictive distributions.
for i_a in range(budget):
log_phi_i = np.array(
select_batch(log_r_model, 1,
"Kriging Believer")).reshape(1, -1)
try:
log_r_i = self.gpr.log_sample(phi=np.exp(log_phi_i))[0]
log_r[i_a:i_a + 1] = log_r_i
log_phi[i_a:i_a + 1, :] = log_phi_i
log_r_model.update(log_phi_i, np.exp(log_r_i).reshape(1, -1))
print(np.exp(log_phi_i), log_r_i)
except np.linalg.linalg.LinAlgError:
print('Error!')
continue
max_log_r = np.max(log_r)
r = np.exp(log_r - max_log_r)
# r = np.exp(log_r)
r_gp = GPy.models.GPRegression(log_phi[:1, :],
np.sqrt(2 * r[0].reshape(1, 1)), kern)
r_model = WarpedIntegrandModel(WsabiLGP(r_gp), self.prior)
r_model.update(log_phi[1:, :], r[1:].reshape(-1, 1))
r_gp.optimize()
r_int_prime = r_model.integral_mean()[0] # Model evidence
r_int = np.exp(np.log(r_int_prime) + max_log_r)
# r_int = r_int_prime
r = np.exp(np.log(log_r) + max_log_r)
print(
"Estimate of model evidence: ",
r_int,
)
# Secondly, compute and marginalise the predictive distribution for each individual points
for i_x in range(test_x.shape[0]):
# Note that we do not active sample again for q, we just use the same samples sampled when we compute
# the log-evidence
_, q_initial, var_initial = self.gpr.log_sample(
phi=np.exp(log_phi_initial), x=test_x[i_x, :])
# Initialise GPy GP surrogate for and q(\phi) - note that this is a BQZ approach and we do not model rq
# as one GP but separate GPs to account for correlation
# Sample for q values
for i_b in range(budget):
log_phi_i = log_phi[i_b, :]
_, q[i_x, i_b], var[i_x, i_b] = self.gpr.log_sample(
phi=np.exp(log_phi_i), x=test_x[i_x, :])
# Enforce positivity in q
q_x = q[i_x, :].copy()
var_x = var[i_x, :].copy()
#sns.distplot(q_x, bins=20)
#plt.axvline(test_y[i_x], color='red', label='Ground Truth')
#plt.xlabel("$\phi$")
#plt.ylabel("$q(\phi)$")
# plt.legend()
#plt.show()
q_min = np.min(q_x)
if q_min < 0:
q_x = q_x - q_min
else:
q_min = 0
# Do the same exponentiation and rescaling trick for q
q_gp = GPy.models.GPRegression(
log_phi[:1, :], np.sqrt(2 * q_x[0].reshape(1, 1)),
GPy.kern.RBF(self.dimensions, variance=2., lengthscale=2.))
q_model = WarpedIntegrandModel(WsabiLGP(q_gp), self.prior)
q_model.update(log_phi[1:, :], q_x[1:].reshape(-1, 1))
q_gp.optimize()
#display(q_gp)
#q_int = q_model.integral_mean()[0]
# Evaluate numerator
alpha_q = q_model.gp._alpha
alpha_r = r_model.gp._alpha
rq_gp = GPy.models.GPRegression(
log_phi, q_model.gp._gp.Y * r_model.gp._gp.Y,
GPy.kern.RBF(self.dimensions, variance=1., lengthscale=1.))
rq_gp.optimize()
#q_sq_gp = GPy.models.GPRegression(log_phi, (q_x - alpha_q).reshape(-1, 1),
# GPy.kern.RBF(self.dimensions,
# variance=2.,
# lengthscale=1.))
#q_sq_gp.optimize()
#r_sq_gp = GPy.models.GPRegression(log_phi, (r-alpha_r).reshape(-1, 1),
# GPy.kern.RBF(self.dimensions,
# variance=1.,
# lengthscale=1.)
# )
#r_sq_gp.optimize()
#display(rq_gp)
#display(q_sq_gp)
#print('---------------')
#display(r_sq_gp)
#display(q_sq_gp)
#print( compute_mean_gp_prod_gpy_2(self.prior, q_gp, q_gp))
#print( q_int )
#exit()
n1 = alpha_r * alpha_q
n2 = 0.5 * alpha_q * compute_mean_gp_prod_gpy_2(
self.prior, r_gp, r_gp)
n3 = 0.5 * alpha_r * compute_mean_gp_prod_gpy_2(
self.prior, q_gp, q_gp)
n4 = 0.25 * compute_mean_gp_prod_gpy_2(self.prior, rq_gp, rq_gp)
n = (n1 + n2 + n3 + n4)
res = n / r_int_prime + q_min
print('res', n1, n2, n3, n4, res)
pred[i_x] = res
#print('final', pred[i_x])
if compute_var:
var_gp = GPy.models.GPRegression(
log_phi[:1, :], np.sqrt(2 * var_x[0].reshape(1, 1)), kern)
var_model = WarpedIntegrandModel(WsabiLGP(var_gp), self.prior)
var_model.update(log_phi[1:, :], var_x[1:].reshape(-1, 1))
var_gp.optimize()
rvar_gp = GPy.models.GPRegression(
log_phi, var_model.gp._gp.Y * r_model.gp._gp.Y, kern)
rvar_gp.optimize()
alpha_var = var_model.gp._alpha
var_num = alpha_r * alpha_var + \
0.5 * alpha_r * compute_mean_gp_prod_gpy_2(self.prior, var_model.gp._gp, var_model.gp._gp) + \
0.5 * alpha_var * compute_mean_gp_prod_gpy_2(self.prior, r_model.gp._gp, r_model.gp._gp) + \
0.25 * (compute_mean_gp_prod_gpy_2(self.prior, rvar_gp, rvar_gp))
pred_var[i_x] = var_num / r_int
logging.info('Progress: ' + str(i_x + 1) + '/' +
str(test_x.shape[0]))
rmse = self.compute_rmse(pred, test_y)
print('Root Mean Squared Error:', rmse)
ll, cs = None, None
if compute_var:
ll, cs = self.compute_ll_cs(pred, pred_var, test_y)
print('Log-likelihood', ll)
print('Calibration score', cs)
end = time.time()
print("Total Time: ", end - start)
print(
"Estimate of model evidence: ",
r_int,
)
print("Model log-evidence ", np.log(r_int))
if verbose:
self.visualise(pred, pred_var, test_y)
return rmse, ll, None, np.log(r_int)
def wsabi(self, verbose=True):
# Allocating number of maximum evaluations
start = time.time()
budget = self.options['wsabi_budget']
batch_count = 1
test_x = self.gpr.X_test
test_y = self.gpr.Y_test
# Allocate memory of the samples and results
log_phi = np.zeros((
budget * batch_count,
self.dimensions,
)) # The log-hyperparameter sampling points
log_r = np.zeros(
(budget * batch_count, )) # The log-likelihood function
q = np.zeros((test_x.shape[0], budget * batch_count)) # Prediction
var = np.zeros(
(test_x.shape[0], budget * batch_count)) # Posterior variance
# Initial points - note that as per GPML convention, the hyperparameters are expressed in log scale
# Initialise to the MAP estimate
map_model, _, _ = self.maximum_a_posterior(num_restarts=1,
max_iters=1000,
verbose=False)
display(map_model)
# mean_vals = map_model.param_array
# self.gpr.reset_params()
if isinstance(self.gpr, PeriodicGPRegression):
pass
#self.gpr.set_params(variance=map_model.std_periodic.variance,
# gaussian_noise=map_model.Gaussian_noise.variance)
elif isinstance(self.gpr, RBFGPRegression):
self.gpr.set_params(
variance=map_model.rbf.variance,
gaussian_noise=map_model.Gaussian_noise.variance)
# Set prior mean to the MAP value
# self.prior = Gaussian(mean=mean_vals.reshape(-1), covariance=self.options['prior_variance'])
log_phi_initial = self.options['prior_mean'].reshape(1, -1)
log_r_initial = np.sqrt(2 * np.exp(
self.gpr.log_sample(phi=np.exp(log_phi_initial.reshape(-1)))[0]))
#log_r_initial = self.gpr.log_sample(
# phi=np.exp(log_phi_initial.reshape(-1)))[0]
pred = np.zeros((test_x.shape[0], ))
pred_var = np.zeros((test_x.shape[0], ))
# Setting up kernel - Note we only marginalise over the lengthscale terms, other hyperparameters are set to the
# MAP values.
kern = GPy.kern.RBF(self.dimensions, variance=1., lengthscale=1)
log_r_gp = GPy.models.GPRegression(log_phi_initial,
log_r_initial.reshape(1, -1), kern)
log_r_model = WarpedIntegrandModel(WsabiLGP(log_r_gp), self.prior)
print(self.prior.mean)
# Firstly, within the given allowance, compute an estimate of the model evidence. Model evidence is the common
# denominator for all predictive distributions.
for i_a in range(budget - 1):
log_phi_i = np.array(
select_batch(log_r_model, batch_count,
"Kriging Believer")).reshape(batch_count, -1)
try:
log_r_i = self.gpr.log_sample(phi=np.exp(log_phi_i))[0]
log_r[i_a:i_a + batch_count] = log_r_i
log_phi[i_a:i_a + batch_count, :] = log_phi_i
log_r_model.update(log_phi_i, np.exp(log_r_i).reshape(1, -1))
print(np.exp(log_phi_i), log_r_i)
except np.linalg.linalg.LinAlgError:
continue
quad_time = time.time()
max_log_r = max(log_r)
# Save the evaluations
log_r_pd = pd.Series(log_r, name='lml')
log_r_pd.to_csv('lml_soton.csv')
r = np.exp(log_r - max_log_r)
r_gp = GPy.models.GPRegression(log_phi[:1, :],
np.sqrt(2 * r[0].reshape(1, 1)), kern)
r_model = WarpedIntegrandModel(WsabiLGP(r_gp), self.prior)
r_model.update(log_phi[1:, :], r[1:].reshape(-1, 1))
r_gp.optimize()
r_int = np.exp(np.log(r_model.integral_mean()[0]) +
max_log_r) # Model evidence
log_r_int = np.log(r_int) # Model log-evidence
# Visualise the model parameter posterior
# neg_log_post = np.array((budget, )) # Negative log-posterior
# rp = np.array((budget, ))
# for i in range(budget):
# neg_log_post[i] = (log_r[i] + self.prior.log_eval(log_phi[i, :]) - log_r_int)
# Then train a GP for the log-posterior surface
# log_posterior_gp = GPy.models.GPRegression(np.exp(log_phi), np.exp(neg_log_post).reshape(-1, 1), kern)
# Secondly, compute and marginalise the predictive distribution for each individual points
for i_x in range(test_x.shape[0]):
# Note that we do not active sample again for q, we just use the same samples sampled when we compute
# the log-evidence
_, q_initial, var_initial = self.gpr.log_sample(
phi=np.exp(log_phi_initial), x=test_x[i_x, :])
# Initialise GPy GP surrogate for and q(\phi)r(\phi)
# Sample for q values
for i_b in range(budget * batch_count):
log_phi_i = log_phi[i_b, :]
log_r_i, q_i, var_i = self.gpr.log_sample(
phi=np.exp(log_phi_i), x=test_x[i_x, :])
q[i_x, i_b] = q_i
var[i_x, i_b] = var_i
# Enforce positivity in q
q_x = q[i_x, :]
var_x = var[i_x, :]
q_min = np.min(q_x)
if q_min < 0:
q_x = q_x - q_min
else:
q_min = 0
# Do the same exponentiation and rescaling trick for q
log_rq_x = log_r + np.log(q_x)
max_log_rq = np.max(log_rq_x)
rq = np.exp(log_rq_x - max_log_rq)
rq_gp = GPy.models.GPRegression(log_phi[:1, :],
np.sqrt(2 * rq[0].reshape(1, 1)),
kern)
rq_model = WarpedIntegrandModel(WsabiLGP(rq_gp), self.prior)
rq_model.update(log_phi[1:, :], rq[1:].reshape(-1, 1))
rq_gp.optimize()
# Now estimate the posterior
# rq_int = rq_model.integral_mean()[0] + q_min * r_int
rq_int = np.exp(np.log(rq_model.integral_mean()[0]) +
max_log_rq) + q_min * r_int
# Similar for variance
log_rvar_x = log_r + np.log(var_x)
max_log_rvar = np.max(log_rvar_x)
rvar = np.exp(log_rvar_x - max_log_rvar)
rvar_gp = GPy.models.GPRegression(
log_phi[:1, :], np.sqrt(2 * rvar[0].reshape(1, 1)), kern)
rvar_model = WarpedIntegrandModel(WsabiLGP(rvar_gp), self.prior)
rvar_model.update(log_phi[1:, :], rvar[1:].reshape(-1, 1))
rvar_gp.optimize()
rvar_int = np.exp(
np.log(rvar_model.integral_mean()[0]) + max_log_rvar)
pred[i_x] = rq_int / r_int
pred_var[i_x] = rvar_int / r_int
print(pred_var[i_x])
logging.info('Progress: ' + str(i_x + 1) + '/' +
str(test_x.shape[0]))
rmse = self.compute_rmse(pred, test_y)
ll, cs = self.compute_ll_cs(pred, pred_var, test_y)
print('Root Mean Squared Error:', rmse)
print('Log-likelihood', ll)
print('Calibration score', cs)
end = time.time()
print("Active Sampling Time: ", quad_time - start)
print("Total Time: ", end - start)
print(
"Estimate of model evidence: ",
r_int,
)
print("Model log-evidence ", log_r_int)
if verbose:
self.visualise(pred, pred_var, test_y)
return rmse, ll, quad_time - start, log_r_int
def wsabi(self, same_query_pts=True):
budget = self.options['wsabi_bq_budget']
samples = np.zeros((budget, self.gpr.dimensions
)) # Array to store all the x locations of samples
lik = np.zeros((
budget, )) # Array to store all the log-likelihoods evaluated at x
intv = np.zeros((budget, ))
# Initial points
initial_x = np.zeros(
(self.dimensions,
1)).reshape(1, -1) # Set the initial sample to the prior mean
initial_y = np.array(self.gpr.sample(initial_x)).reshape(1, -1)
# Setting up kernel
kern = GPy.kern.RBF(
self.dimensions,
variance=self.options['naive_bq_kern_variance'],
lengthscale=self.options['naive_bq_kern_lengthscale'])
# Initial guess for the GP for BQ
gpy_gp_lik = GPy.models.GPRegression(
initial_x,
initial_y,
kernel=kern,
)
warped_gp = WsabiLGP(gpy_gp_lik)
model = WarpedIntegrandModel(warped_gp, prior=self.prior)
for i in range(budget):
samples[i, :] = np.array(
select_batch(model, 1, 'Local Penalisation')).reshape(1, -1)
lik[i] = np.array(self.gpr.sample(samples[i, :])).reshape(1, -1)
model.update(samples[i, :], lik[i])
gpy_gp_lik.optimize()
intv = model.integral_mean()[0]
print("Integral mean estimated:", intv)
# Generate query points meshgrid for the posterior distribution and the priors evaluated on these points
if same_query_pts:
query_points = np.empty((budget + 1, self.gpr.dimensions))
query_points[0] = initial_x
query_points[1:] = samples
prior_query_points = self.prior(query_points)
unwarped_y = np.squeeze(warped_gp._unwarped_Y)
else:
query_points, prior_query_points = self._gen_meshgrid_query_points(
)
# Evaluate at the query points on the likelihood surface generated by the GP surrogate
warped_lik = gpy_gp_lik.predict(query_points)[0]
# Unwarp the warped likelihood outputs
unwarped_y = self.unwarp(warped_lik, warped_gp._alpha)
posterior_query_points = (unwarped_y * prior_query_points /
intv).reshape(-1, 1)
# Initialise another GP for the posterior distribution
gpy_gp_post = GPy.models.GPRegression(
query_points,
posterior_query_points,
kernel=kern,
)
gpy_gp_post.optimize()
#plt.subplot(211)
#gpy_gp_lik.plot()
#plt.subplot(212)
gpy_gp_post.plot(plot_limits=[[-5, -5], [5, 5]])
plt.show()
def wsabi(X_pred,
y_grd,
log_lik_handle,
param_dim=5,
prior_mean=np.zeros((5, 1)),
prior_var=100 * np.eye(5)):
# Allocating number of maximum evaluations
start = time.time()
prior = Gaussian(mean=prior_mean.reshape(-1), covariance=prior_var)
# Initial grid sampling
log_phis = np.mgrid[-1:1.1:1, -1:1.1:1, -1:1.1:1, -1:1.1:1,
0:25:5].reshape(5, -1).T
n = log_phis.shape[0]
phis = log_phis.copy()
phis[:, :-1] = np.exp(phis[:, :-1])
# Allocate memory of the samples and results
log_r = np.zeros((n, 1)) # The log-likelihood function
q = np.zeros((n, 1)) # Prediction
# var = np.zeros((n, )) # Posterior variance
for i in range(n):
log_r[i, :], q[i, :], _ = log_lik_handle(phi=phis[i, :], x_pred=X_pred)
print(phis[i, :], log_r[i, :], q[i, :])
r = np.exp(log_r)
# Setting up kernel - Note we only marginalise over the lengthscale terms, other hyperparameters are set to the
# MAP values.
kern = GPy.kern.RBF(param_dim, variance=1., lengthscale=1.)
# kern.plot(ax=plt.gca())
r_gp = GPy.models.GPRegression(phis[:1, :], r[:1, :], kern)
r_model = WarpedIntegrandModel(WsabiLGP(r_gp), prior)
r_model.update(phis[1:, :], r[1:, :])
r_gp.optimize()
r_int = r_model.integral_mean()[0] # Model evidence
log_r_int = np.log(r_int) # Model log-evidence
print(
"Estimate of model evidence: ",
r_int,
)
print("Model log-evidence ", log_r_int)
# Enforce positivity in q
q_min = np.min(q)
if q_min < 0:
q -= q_min
else:
q_min = 0
# Do the same exponentiation and rescaling trick for q
log_rq_x = log_r + np.log(q)
max_log_rq = np.max(log_rq_x)
rq = np.exp(log_rq_x - max_log_rq)
rq_gp = GPy.models.GPRegression(phis, np.sqrt(2 * rq.reshape(-1, 1)), kern)
rq_model = WarpedIntegrandModel(WsabiLGP(rq_gp), prior)
rq_model.update(phis, rq)
rq_gp.optimize()
# Now estimate the posterior
# rq_int = rq_model.integral_mean()[0] + q_min * r_int
rq_int = np.exp(np.log(rq_model.integral_mean()[0]) +
max_log_rq) + q_min * r_int
print("rq_int", rq_int)
# Similar for variance
#log_rvar_x = log_r + np.log(var)
#max_log_rvar = np.max(log_rvar_x)
#rvar = np.exp(log_rvar_x - max_log_rvar)
#rvar_gp = GPy.models.GPRegression(phis[:1, :], np.sqrt(2 * rvar[0].reshape(1, 1)), kern)
#rvar_model = WarpedIntegrandModel(WsabiLGP(rvar_gp), prior)
#rvar_model.update(phis[1:, :], rvar[1:].reshape(-1, 1))
#rvar_gp.optimize()
#rvar_int = np.exp(np.log(rvar_model.integral_mean()[0]) + max_log_rvar)
pred = rq_int / r_int
#pred_var = rvar_int / r_int
print('pred', pred)
print('actual', y_grd)
end = time.time()
print("Total Time: ", end - start)
return pred, None
def wsabi_bq(self, rebase=False):
"""
Marginalise the marginal log-likelihood using WSABI Bayesian Quadrature
:return:
"""
budget = self.options['naive_bq_budget']
samples = np.zeros((budget, self.gpr.dimensions
)) # Array to store all the x locations of samples
yv = np.zeros((
budget, )) # Array to store all the log-likelihoods evaluated at x
yv_scaled = np.zeros((budget, ))
intv = np.zeros(
(budget, )
) # Array to store the current estimate of the marginalised integral
log_intv = np.zeros((budget, ))
# Initial points
initial_x = np.zeros((self.dimensions, 1)).reshape(
1, -1) + 1e-6 # Set the initial sample to the prior mean
if rebase:
initial_y = np.array([1]).reshape(1, -1)
else:
initial_y = np.array(self.gpr.sample(initial_x)).reshape(1, -1)
# Prior in log space
prior_mean = self.options['prior_mean'].reshape(-1)
prior_cov = self.options['prior_variance']
prior = Gaussian(mean=prior_mean, covariance=prior_cov)
# Setting up kernel - noting the log-transformation
kern = GPy.kern.RBF(
self.dimensions,
variance=self.options['naive_bq_kern_variance'],
lengthscale=self.options['naive_bq_kern_lengthscale'])
# Initial guess for the GP for BQ
gpy_gp = GPy.models.GPRegression(
initial_x,
initial_y,
kernel=kern,
)
warped_gp = WsabiLGP(gpy_gp)
model = WarpedIntegrandModel(warped_gp, prior=prior)
if rebase:
for i in range(budget):
samples[i, :] = np.array(
select_batch(model, 1, LOCAL_PENALISATION)).reshape(1, -1)
yv[i] = np.array(self.gpr.log_sample(samples[i, :])).reshape(
1, -1)
scaling = np.max(yv[:i + 1])
yv_scaled[:i + 1] = np.exp(yv[:i + 1] - scaling)
x = samples[:i + 1]
y = yv_scaled[:i + 1].reshape(-1, 1)
if i % 20 == 0 and i > 0:
# Create a new model since all x and y data have been replaced due to rebasing
gpy_gp = GPy.models.GPRegression(
x,
y,
kernel=kern,
)
warped_gp = WsabiLGP(gpy_gp)
model = WarpedIntegrandModel(warped_gp, prior)
gpy_gp.optimize()
log_intv[i] = np.log((model.integral_mean())[0]) + scaling
intv[i] = np.exp(log_intv[i])
if i % 100 == 0:
self.plot_iterations(i,
log_intv,
true_val=self.gpr.grd_log_evidence)
else:
for i in range(budget):
samples[i, :] = np.array(
select_batch(model, 1, LOCAL_PENALISATION)).reshape(1, -1)
yv[i] = np.array(self.gpr.sample(samples[i, :])).reshape(1, -1)
model.update(samples[i, :], yv[i])
gpy_gp.optimize()
intv[i] = (model.integral_mean())[0]
log_intv[i] = np.log(intv[i])
if i % 100 == 0:
self.plot_iterations(i,
log_intv,
true_val=self.gpr.grd_log_evidence) #
gpy_gp.plot()
plt.show()
return yv[-1], intv[-1]
def wsabi(gpy_gp: GPy.core.GP, x, kern=None, noise=None):
"""Initial grid sampling, followed by WSABI quadrature"""
from ratio.posterior_mc_inference import PosteriorMCSampler
budget = 50
x = np.array(x).reshape(1, 1)
#sampler = PosteriorMCSampler(gpy_gp)
#log_params = np.log(sampler.hmc(num_iters=budget, mode='gpy'))
#print(log_params)
log_params = np.empty((budget, 3))
#for i in range(budget):
# log_params[i, :] = scipy.stats.multivariate_normal.rvs(mean=np.array([0, 0, 0]), cov=4*np.eye(3))
log_params = np.mgrid[0:4.1:1, 0:4.1:1, -4:-0.1:1.5].reshape(3, -1).T
budget = log_params.shape[0]
if kern is None:
kern = GPy.kern.RBF(input_dim=1, variance=1., lengthscale=1.)
if noise is None:
noise = 1e-3
prior = Gaussian(mean=np.array([0, 0, 0]), covariance=4 * np.eye(3))
log_phis = np.empty((budget, 3))
log_liks = np.empty((budget, ))
pred_means = np.empty((budget, ))
pred_vars = np.empty((budget, ))
for i in range(log_params.shape[0]):
log_phi = log_params[i, :]
_set_model(gpy_gp, np.exp(log_phi))
log_lik = gpy_gp.log_likelihood()
#print('params', log_phi, log_lik)
log_phis[i] = log_phi
log_liks[i] = log_lik
pred_means[i], pred_vars[i] = gpy_gp.predict_noiseless(x)
if np.max(log_liks) > 15.:
# For highly peaked likelihoods, we do not use quadrature and simply use MAP estimate
idx = log_liks.argmax()
return pred_means[idx], pred_vars[idx], kern, noise
r_gp = GPy.models.GPRegression(
log_params[:1, :],
np.sqrt(2 * np.exp(log_liks[0])).reshape(1, -1), kern)
r_gp.Gaussian_noise.variance = noise
r_model = WarpedIntegrandModel(WsabiLGP(r_gp), prior)
r_model.update(log_phis[1:, :], np.exp(log_liks[1:]).reshape(1, -1))
#print(r_gp.X, r_gp.Y)
#from IPython.display import display
#display(r_gp)
r_gp.optimize()
r_int = r_model.integral_mean()[0]
q_min = np.min(pred_means)
pred_means -= q_min
rq = np.exp(log_liks) * pred_means
rq_gp = GPy.models.GPRegression(log_phis[:1, :],
np.sqrt(2 * rq[0]).reshape(1, -1), kern)
rq_model = WarpedIntegrandModel((WsabiLGP(rq_gp)), prior)
rq_model.update(log_phis[1:, :], rq[1:].reshape(1, -1))
rq_gp.optimize()
rq_int = rq_model.integral_mean()[0] + q_min * r_int
rvar = np.exp(log_liks) * pred_vars
rvar_gp = GPy.models.GPRegression(log_phis[:1, :],
np.sqrt(2 * rvar[0]).reshape(1, -1),
kern)
rvar_model = WarpedIntegrandModel((WsabiLGP(rvar_gp)), prior)
rvar_model.update(log_phis[1:, :], rvar[1:].reshape(1, -1))
rvar_gp.optimize()
rvar_int = rvar_model.integral_mean()[0]
return rq_int / r_int, rvar_int / r_int, r_gp.kern, r_gp.Gaussian_noise.variance