def posterior(
self,
X: Tensor,
output_indices: Optional[List[int]] = None,
observation_noise: Union[bool, Tensor] = False,
**kwargs: Any,
) -> GPyTorchPosterior:
r"""Computes the posterior over model outputs at the provided points.
Args:
X: A `q x d` or `batch_shape x q x d` (batch mode) tensor, where `d` is the
dimension of the feature space (not including task indices) and
`q` is the number of points considered jointly.
output_indices: A list of indices, corresponding to the outputs over
which to compute the posterior (if the model is multi-output).
Can be used to speed up computation if only a subset of the
model's outputs are required for optimization. If omitted,
computes the posterior over all model outputs.
observation_noise: If True, add observation noise from the respective
likelihoods. If a Tensor, specifies the observation noise levels
to add.
Returns:
A `GPyTorchPosterior` object, representing `batch_shape` joint
distributions over `q` points and the outputs selected by
`output_indices`. Includes measurement noise if
`observation_noise` is specified.
"""
if output_indices is None:
output_indices = self._output_tasks
if any(i not in self._output_tasks for i in output_indices):
raise ValueError("Too many output indices")
cls_name = self.__class__.__name__
if hasattr(self, "outcome_transform"):
raise NotImplementedError(
f"Outcome transforms currently not supported by {cls_name}")
# construct evaluation X
X_full = _make_X_full(X=X,
output_indices=output_indices,
tf=self._task_feature)
self.eval() # make sure model is in eval mode
with gpt_posterior_settings():
mvn = self(X_full)
if observation_noise is not False:
raise NotImplementedError(
f"Specifying observation noise is not yet supported by {cls_name}"
)
# If single-output, return the posterior of a single-output model
if len(output_indices) == 1:
return GPyTorchPosterior(mvn=mvn)
# Otherwise, make a MultitaskMultivariateNormal out of this
mtmvn = MultitaskMultivariateNormal(
mean=mvn.mean.view(*X.shape[:-1], len(output_indices)),
covariance_matrix=mvn.lazy_covariance_matrix,
interleaved=False,
)
return GPyTorchPosterior(mvn=mtmvn)
def test_transformed_posterior(self):
for dtype in (torch.float, torch.double):
for m in (1, 2):
shape = torch.Size([3, m])
mean = torch.rand(shape, dtype=dtype, device=self.device)
variance = 1 + torch.rand(
shape, dtype=dtype, device=self.device)
if m == 1:
covar = torch.diag_embed(variance.squeeze(-1))
mvn = MultivariateNormal(mean.squeeze(-1), lazify(covar))
else:
covar = torch.diag_embed(
variance.view(*variance.shape[:-2], -1))
mvn = MultitaskMultivariateNormal(mean, lazify(covar))
p_base = GPyTorchPosterior(mvn=mvn)
p_tf = TransformedPosterior( # dummy transforms
posterior=p_base,
sample_transform=lambda s: s + 2,
mean_transform=lambda m, v: 2 * m + v,
variance_transform=lambda m, v: m + 2 * v,
)
# mean, variance
self.assertEqual(p_tf.device.type, self.device.type)
self.assertTrue(p_tf.dtype == dtype)
self.assertEqual(p_tf.event_shape, shape)
self.assertEqual(p_tf.base_sample_shape, shape)
self.assertTrue(torch.equal(p_tf.mean, 2 * mean + variance))
self.assertTrue(torch.equal(p_tf.variance,
mean + 2 * variance))
# rsample
samples = p_tf.rsample()
self.assertEqual(samples.shape, torch.Size([1]) + shape)
samples = p_tf.rsample(sample_shape=torch.Size([4]))
self.assertEqual(samples.shape, torch.Size([4]) + shape)
samples2 = p_tf.rsample(sample_shape=torch.Size([4, 2]))
self.assertEqual(samples2.shape, torch.Size([4, 2]) + shape)
# rsample w/ base samples
base_samples = torch.randn(4,
*shape,
device=self.device,
dtype=dtype)
# incompatible shapes
with self.assertRaises(RuntimeError):
p_tf.rsample(sample_shape=torch.Size([3]),
base_samples=base_samples)
# make sure sample transform is applied correctly
samples_base = p_base.rsample(sample_shape=torch.Size([4]),
base_samples=base_samples)
samples_tf = p_tf.rsample(sample_shape=torch.Size([4]),
base_samples=base_samples)
self.assertTrue(torch.equal(samples_tf, samples_base + 2))
# check error handling
p_tf_2 = TransformedPosterior(posterior=p_base,
sample_transform=lambda s: s + 2)
with self.assertRaises(NotImplementedError):
p_tf_2.mean
with self.assertRaises(NotImplementedError):
p_tf_2.variance
def test_degenerate_GPyTorchPosterior(self, cuda=False):
device = torch.device("cuda") if cuda else torch.device("cpu")
for dtype in (torch.float, torch.double):
# singular covariance matrix
degenerate_covar = torch.tensor(
[[1, 1, 0], [1, 1, 0], [0, 0, 2]], dtype=dtype, device=device
)
mean = torch.rand(3, dtype=dtype, device=device)
mvn = MultivariateNormal(mean, lazify(degenerate_covar))
posterior = GPyTorchPosterior(mvn=mvn)
# basics
self.assertEqual(posterior.device.type, device.type)
self.assertTrue(posterior.dtype == dtype)
self.assertEqual(posterior.event_shape, torch.Size([3, 1]))
self.assertTrue(torch.equal(posterior.mean, mean.unsqueeze(-1)))
variance_exp = degenerate_covar.diag().unsqueeze(-1)
self.assertTrue(torch.equal(posterior.variance, variance_exp))
# rsample
with warnings.catch_warnings(record=True) as w:
# we check that the p.d. warning is emitted - this only
# happens once per posterior, so we need to check only once
samples = posterior.rsample(sample_shape=torch.Size([4]))
self.assertEqual(len(w), 1)
self.assertTrue(issubclass(w[-1].category, RuntimeWarning))
self.assertTrue("not p.d." in str(w[-1].message))
self.assertEqual(samples.shape, torch.Size([4, 3, 1]))
samples2 = posterior.rsample(sample_shape=torch.Size([4, 2]))
self.assertEqual(samples2.shape, torch.Size([4, 2, 3, 1]))
# rsample w/ base samples
base_samples = torch.randn(4, 3, 1, device=device, dtype=dtype)
samples_b1 = posterior.rsample(
sample_shape=torch.Size([4]), base_samples=base_samples
)
samples_b2 = posterior.rsample(
sample_shape=torch.Size([4]), base_samples=base_samples
)
self.assertTrue(torch.allclose(samples_b1, samples_b2))
base_samples2 = torch.randn(4, 2, 3, 1, device=device, dtype=dtype)
samples2_b1 = posterior.rsample(
sample_shape=torch.Size([4, 2]), base_samples=base_samples2
)
samples2_b2 = posterior.rsample(
sample_shape=torch.Size([4, 2]), base_samples=base_samples2
)
self.assertTrue(torch.allclose(samples2_b1, samples2_b2))
# collapse_batch_dims
b_mean = torch.rand(2, 3, dtype=dtype, device=device)
b_degenerate_covar = degenerate_covar.expand(2, *degenerate_covar.shape)
b_mvn = MultivariateNormal(b_mean, lazify(b_degenerate_covar))
b_posterior = GPyTorchPosterior(mvn=b_mvn)
b_base_samples = torch.randn(4, 2, 3, 1, device=device, dtype=dtype)
with warnings.catch_warnings(record=True) as w:
b_samples = b_posterior.rsample(
sample_shape=torch.Size([4]), base_samples=b_base_samples
)
self.assertEqual(len(w), 1)
self.assertTrue(issubclass(w[-1].category, RuntimeWarning))
self.assertTrue("not p.d." in str(w[-1].message))
self.assertEqual(b_samples.shape, torch.Size([4, 2, 3, 1]))
def posterior(self,
X: Tensor,
observation_noise: Union[bool, Tensor] = False,
**kwargs: Any) -> GPyTorchPosterior:
r"""Computes the posterior over model outputs at the provided points.
Args:
X: A `(batch_shape) x q x d`-dim Tensor, where `d` is the dimension
of the feature space and `q` is the number of points considered
jointly.
observation_noise: If True, add the observation noise from the
likelihood to the posterior. If a Tensor, use it directly as the
observation noise (must be of shape `(batch_shape) x q`).
Returns:
A `GPyTorchPosterior` object, representing a batch of `b` joint
distributions over `q` points. Includes observation noise if
specified.
"""
self.eval() # make sure model is in eval mode
with gpt_posterior_settings():
mvn = self(X)
if observation_noise is not False:
if torch.is_tensor(observation_noise):
# TODO: Make sure observation noise is transformed correctly
self._validate_tensor_args(X=X, Y=observation_noise)
if observation_noise.size(-1) == 1:
observation_noise = observation_noise.squeeze(-1)
mvn = self.likelihood(mvn, X, noise=observation_noise)
else:
mvn = self.likelihood(mvn, X)
posterior = GPyTorchPosterior(mvn=mvn)
if hasattr(self, "outcome_transform"):
posterior = self.outcome_transform.untransform_posterior(posterior)
return posterior
def posterior(
self,
X: Tensor,
output_indices: Optional[List[int]] = None,
observation_noise: bool = False,
**kwargs: Any,
) -> Posterior:
r"""Computes the posterior over model outputs at the provided points.
Args:
X: A `batch_shape x q x d`-dim Tensor, where `d` is the dimension
of the feature space and `q` is the number of points considered jointly.
output_indices: As defined in parent Model class, not used for this model.
observation_noise: If True, add observation noise to the posterior.
Returns:
A `Posterior` object, representing joint
distributions over `q` points. Includes observation noise if specified.
"""
self.eval() # make sure model is in eval mode
if output_indices is not None:
raise RuntimeError(
"output_indices is not None. PairwiseGP should not be a"
"multi-output model.")
post = self(X)
if observation_noise:
noise_module = self.noise_module(shape=post.mean.shape).evaluate()
post = MultivariateNormal(post.mean,
post.covariance_matrix + noise_module)
return GPyTorchPosterior(post)
def posterior(
self,
X: Tensor,
output_indices: Optional[List[int]] = None,
observation_noise: bool = False,
**kwargs: Any,
) -> Posterior:
r"""Computes the posterior over model outputs at the provided points.
Args:
X: A `batch_shape x q x d`-dim Tensor, where `d` is the dimension
of the feature space and `q` is the number of points considered jointly.
output_indices: As defined in parent Model class, not used for this model.
observation_noise: Ignored (since noise is not identifiable from scale
in probit models).
Returns:
A `Posterior` object, representing joint
distributions over `q` points.
"""
self.eval() # make sure model is in eval mode
if output_indices is not None:
raise RuntimeError(
"output_indices is not None. PairwiseGP should not be a"
"multi-output model.")
post = self(X)
return GPyTorchPosterior(post)
def posterior(self,
X,
output_indices=None,
observation_noise=False,
*args,
**kwargs) -> GPyTorchPosterior:
self.eval() # make sure model is in eval mode
# input transforms are applied at `posterior` in `eval` mode, and at
# `model.forward()` at the training time
X = self.transform_inputs(X)
# check for the multi-batch case for multi-outputs b/c this will throw
# warnings
X_ndim = X.ndim
if self.num_outputs > 1 and X_ndim > 2:
X = X.unsqueeze(-3).repeat(*[1] * (X_ndim - 2), self.num_outputs,
1, 1)
dist = self.model(X)
if observation_noise:
dist = self.likelihood(dist, *args, **kwargs)
posterior = GPyTorchPosterior(mvn=dist)
if hasattr(self, "outcome_transform"):
posterior = self.outcome_transform.untransform_posterior(posterior)
return posterior
def _get_test_posterior(batch_shape, q=1, m=1, **tkwargs):
mean = torch.rand(*batch_shape, q, m, **tkwargs)
a = torch.rand(*batch_shape, q * m, q * m, **tkwargs)
covar = a @ a.transpose(-1, -2)
diag = torch.diagonal(covar, dim1=-2, dim2=-1)
diag += torch.rand(*batch_shape, q * m, **tkwargs) # in-place
mvn = MultitaskMultivariateNormal(mean, covar)
return GPyTorchPosterior(mvn)
def _get_test_posterior(batch_shape, device, dtype, q=1, o=1):
mean = torch.rand(*batch_shape, q, o, device=device, dtype=dtype)
a = torch.rand(*batch_shape, q * o, q * o, device=device, dtype=dtype)
covar = a @ a.transpose(-1, -2)
diag = torch.diagonal(covar, dim1=-2, dim2=-1)
diag += torch.rand(*batch_shape, q * o, device=device,
dtype=dtype) # in-place
mvn = MultitaskMultivariateNormal(mean, covar)
return GPyTorchPosterior(mvn)
def test_GPyTorchPosterior_Multitask(self, cuda=False):
device = torch.device("cuda") if cuda else torch.device("cpu")
for dtype in (torch.float, torch.double):
mean = torch.rand(3, 2, dtype=dtype, device=device)
variance = 1 + torch.rand(3, 2, dtype=dtype, device=device)
covar = variance.view(-1).diag()
mvn = MultitaskMultivariateNormal(mean, lazify(covar))
posterior = GPyTorchPosterior(mvn=mvn)
# basics
self.assertEqual(posterior.device.type, device.type)
self.assertTrue(posterior.dtype == dtype)
self.assertEqual(posterior.event_shape, torch.Size([3, 2]))
self.assertTrue(torch.equal(posterior.mean, mean))
self.assertTrue(torch.equal(posterior.variance, variance))
# rsample
samples = posterior.rsample(sample_shape=torch.Size([4]))
self.assertEqual(samples.shape, torch.Size([4, 3, 2]))
samples2 = posterior.rsample(sample_shape=torch.Size([4, 2]))
self.assertEqual(samples2.shape, torch.Size([4, 2, 3, 2]))
# rsample w/ base samples
base_samples = torch.randn(4, 3, 2, device=device, dtype=dtype)
samples_b1 = posterior.rsample(
sample_shape=torch.Size([4]), base_samples=base_samples
)
samples_b2 = posterior.rsample(
sample_shape=torch.Size([4]), base_samples=base_samples
)
self.assertTrue(torch.allclose(samples_b1, samples_b2))
base_samples2 = torch.randn(4, 2, 3, 2, device=device, dtype=dtype)
samples2_b1 = posterior.rsample(
sample_shape=torch.Size([4, 2]), base_samples=base_samples2
)
samples2_b2 = posterior.rsample(
sample_shape=torch.Size([4, 2]), base_samples=base_samples2
)
self.assertTrue(torch.allclose(samples2_b1, samples2_b2))
# collapse_batch_dims
b_mean = torch.rand(2, 3, 2, dtype=dtype, device=device)
b_variance = 1 + torch.rand(2, 3, 2, dtype=dtype, device=device)
b_covar = b_variance.view(2, 6, 1) * torch.eye(6).type_as(b_variance)
b_mvn = MultitaskMultivariateNormal(b_mean, lazify(b_covar))
b_posterior = GPyTorchPosterior(mvn=b_mvn)
b_base_samples = torch.randn(4, 1, 3, 2, device=device, dtype=dtype)
b_samples = b_posterior.rsample(
sample_shape=torch.Size([4]), base_samples=b_base_samples
)
self.assertEqual(b_samples.shape, torch.Size([4, 2, 3, 2]))
def posterior(
self,
X: Tensor,
output_indices: Optional[List[int]] = None,
observation_noise: Union[bool, Tensor] = False,
**kwargs: Any,
) -> GPyTorchPosterior:
assert output_indices is None
assert not observation_noise
mvn = self(X)
return GPyTorchPosterior(mvn=mvn)
def posterior(self,
X,
output_indices=None,
observation_noise=False,
*args,
**kwargs):
self.model.eval()
self.likelihood.eval()
dist = self.model(X)
if observation_noise:
dist = self.likelihood(dist, *args, **kwargs)
return GPyTorchPosterior(mvn=dist)
def _get_test_posterior(batch_shape: torch.Size,
q: int = 1,
m: int = 1,
interleaved: bool = True,
lazy: bool = False,
independent: bool = False,
**tkwargs) -> GPyTorchPosterior:
r"""Generate a Posterior for testing purposes.
Args:
batch_shape: The batch shape of the data.
q: The number of candidates
m: The number of outputs.
interleaved: A boolean indicating the format of the
MultitaskMultivariateNormal
lazy: A boolean indicating if the posterior should be lazy
indepedent: A boolean indicating whether the outputs are independent
tkwargs: `device` and `dtype` tensor constructor kwargs.
"""
if independent:
mvns = []
for _ in range(m):
mean = torch.rand(*batch_shape, q, **tkwargs)
a = torch.rand(*batch_shape, q, q, **tkwargs)
covar = a @ a.transpose(-1, -2)
flat_diag = torch.rand(*batch_shape, q, **tkwargs)
covar = covar + torch.diag_embed(flat_diag)
mvns.append(MultivariateNormal(mean, covar))
mtmvn = MultitaskMultivariateNormal.from_independent_mvns(mvns)
else:
mean = torch.rand(*batch_shape, q, m, **tkwargs)
a = torch.rand(*batch_shape, q * m, q * m, **tkwargs)
covar = a @ a.transpose(-1, -2)
flat_diag = torch.rand(*batch_shape, q * m, **tkwargs)
if lazy:
covar = AddedDiagLazyTensor(covar, DiagLazyTensor(flat_diag))
else:
covar = covar + torch.diag_embed(flat_diag)
mtmvn = MultitaskMultivariateNormal(mean,
covar,
interleaved=interleaved)
return GPyTorchPosterior(mtmvn)
def test_evaluate_q_knowledge_gradient(self):
for dtype in (torch.float, torch.double):
# basic test
n_f = 4
mean = torch.rand(n_f, 1, 1, device=self.device, dtype=dtype)
variance = torch.rand(n_f, 1, 1, device=self.device, dtype=dtype)
mfm = MockModel(MockPosterior(mean=mean, variance=variance))
with mock.patch.object(MockModel, "fantasize", return_value=mfm) as patch_f:
with mock.patch(NO, new_callable=mock.PropertyMock) as mock_num_outputs:
mock_num_outputs.return_value = 1
mm = MockModel(None)
qKG = qKnowledgeGradient(model=mm, num_fantasies=n_f)
X = torch.rand(n_f + 1, 1, device=self.device, dtype=dtype)
val = qKG(X)
patch_f.assert_called_once()
cargs, ckwargs = patch_f.call_args
self.assertEqual(ckwargs["X"].shape, torch.Size([1, 1, 1]))
self.assertTrue(torch.allclose(val, mean.mean(), atol=1e-4))
self.assertTrue(torch.equal(qKG.extract_candidates(X), X[..., :-n_f, :]))
# batched evaluation
b = 2
mean = torch.rand(n_f, b, 1, device=self.device, dtype=dtype)
variance = torch.rand(n_f, b, 1, device=self.device, dtype=dtype)
mfm = MockModel(MockPosterior(mean=mean, variance=variance))
X = torch.rand(b, n_f + 1, 1, device=self.device, dtype=dtype)
with mock.patch.object(MockModel, "fantasize", return_value=mfm) as patch_f:
with mock.patch(NO, new_callable=mock.PropertyMock) as mock_num_outputs:
mock_num_outputs.return_value = 1
mm = MockModel(None)
qKG = qKnowledgeGradient(model=mm, num_fantasies=n_f)
val = qKG(X)
patch_f.assert_called_once()
cargs, ckwargs = patch_f.call_args
self.assertEqual(ckwargs["X"].shape, torch.Size([b, 1, 1]))
self.assertTrue(
torch.allclose(val, mean.mean(dim=0).squeeze(-1), atol=1e-4)
)
self.assertTrue(torch.equal(qKG.extract_candidates(X), X[..., :-n_f, :]))
# pending points and current value
X_pending = torch.rand(2, 1, device=self.device, dtype=dtype)
mean = torch.rand(n_f, 1, 1, device=self.device, dtype=dtype)
variance = torch.rand(n_f, 1, 1, device=self.device, dtype=dtype)
mfm = MockModel(MockPosterior(mean=mean, variance=variance))
current_value = torch.rand(1, device=self.device, dtype=dtype)
X = torch.rand(n_f + 1, 1, device=self.device, dtype=dtype)
with mock.patch.object(MockModel, "fantasize", return_value=mfm) as patch_f:
with mock.patch(NO, new_callable=mock.PropertyMock) as mock_num_outputs:
mock_num_outputs.return_value = 1
mm = MockModel(None)
qKG = qKnowledgeGradient(
model=mm,
num_fantasies=n_f,
X_pending=X_pending,
current_value=current_value,
)
val = qKG(X)
patch_f.assert_called_once()
cargs, ckwargs = patch_f.call_args
self.assertEqual(ckwargs["X"].shape, torch.Size([1, 3, 1]))
self.assertTrue(torch.allclose(val, mean.mean() - current_value, atol=1e-4))
self.assertTrue(torch.equal(qKG.extract_candidates(X), X[..., :-n_f, :]))
# test objective (inner MC sampling)
objective = GenericMCObjective(objective=lambda Y, X: Y.norm(dim=-1))
samples = torch.randn(3, 1, 1, device=self.device, dtype=dtype)
mfm = MockModel(MockPosterior(samples=samples))
X = torch.rand(n_f + 1, 1, device=self.device, dtype=dtype)
with mock.patch.object(MockModel, "fantasize", return_value=mfm) as patch_f:
with mock.patch(NO, new_callable=mock.PropertyMock) as mock_num_outputs:
mock_num_outputs.return_value = 1
mm = MockModel(None)
qKG = qKnowledgeGradient(
model=mm, num_fantasies=n_f, objective=objective
)
val = qKG(X)
patch_f.assert_called_once()
cargs, ckwargs = patch_f.call_args
self.assertEqual(ckwargs["X"].shape, torch.Size([1, 1, 1]))
self.assertTrue(torch.allclose(val, objective(samples).mean(), atol=1e-4))
self.assertTrue(torch.equal(qKG.extract_candidates(X), X[..., :-n_f, :]))
# test non-MC objective (ScalarizedObjective)
weights = torch.rand(2, device=self.device, dtype=dtype)
objective = ScalarizedObjective(weights=weights)
mean = torch.tensor([1.0, 0.5], device=self.device, dtype=dtype).expand(
n_f, 1, 2
)
cov = torch.tensor(
[[1.0, 0.1], [0.1, 0.5]], device=self.device, dtype=dtype
).expand(n_f, 2, 2)
posterior = GPyTorchPosterior(MultitaskMultivariateNormal(mean, cov))
mfm = MockModel(posterior)
with mock.patch.object(MockModel, "fantasize", return_value=mfm) as patch_f:
with mock.patch(NO, new_callable=mock.PropertyMock) as mock_num_outputs:
mock_num_outputs.return_value = 2
mm = MockModel(None)
qKG = qKnowledgeGradient(
model=mm, num_fantasies=n_f, objective=objective
)
val = qKG(X)
patch_f.assert_called_once()
cargs, ckwargs = patch_f.call_args
self.assertEqual(ckwargs["X"].shape, torch.Size([1, 1, 1]))
val_expected = (mean * weights).sum(-1).mean(0)
self.assertTrue(torch.allclose(val, val_expected))
def test_construct_base_samples_from_posterior(self): # noqa: C901
for dtype in (torch.float, torch.double):
# single-output
mean = torch.zeros(2, device=self.device, dtype=dtype)
cov = torch.eye(2, device=self.device, dtype=dtype)
mvn = MultivariateNormal(mean=mean, covariance_matrix=cov)
posterior = GPyTorchPosterior(mvn=mvn)
for sample_shape, qmc, seed in itertools.product(
(torch.Size([5]), torch.Size([5, 3])), (False, True), (None, 1234)
):
expected_shape = sample_shape + torch.Size([2, 1])
samples = construct_base_samples_from_posterior(
posterior=posterior, sample_shape=sample_shape, qmc=qmc, seed=seed
)
self.assertEqual(samples.shape, expected_shape)
self.assertEqual(samples.device.type, self.device.type)
self.assertEqual(samples.dtype, dtype)
# single-output, batch mode
mean = torch.zeros(2, 2, device=self.device, dtype=dtype)
cov = torch.eye(2, device=self.device, dtype=dtype).expand(2, 2, 2)
mvn = MultivariateNormal(mean=mean, covariance_matrix=cov)
posterior = GPyTorchPosterior(mvn=mvn)
for sample_shape, qmc, seed, collapse_batch_dims in itertools.product(
(torch.Size([5]), torch.Size([5, 3])),
(False, True),
(None, 1234),
(False, True),
):
if collapse_batch_dims:
expected_shape = sample_shape + torch.Size([1, 2, 1])
else:
expected_shape = sample_shape + torch.Size([2, 2, 1])
samples = construct_base_samples_from_posterior(
posterior=posterior,
sample_shape=sample_shape,
qmc=qmc,
collapse_batch_dims=collapse_batch_dims,
seed=seed,
)
self.assertEqual(samples.shape, expected_shape)
self.assertEqual(samples.device.type, self.device.type)
self.assertEqual(samples.dtype, dtype)
# multi-output
mean = torch.zeros(2, 2, device=self.device, dtype=dtype)
cov = torch.eye(4, device=self.device, dtype=dtype)
mtmvn = MultitaskMultivariateNormal(mean=mean, covariance_matrix=cov)
posterior = GPyTorchPosterior(mvn=mtmvn)
for sample_shape, qmc, seed in itertools.product(
(torch.Size([5]), torch.Size([5, 3])), (False, True), (None, 1234)
):
expected_shape = sample_shape + torch.Size([2, 2])
samples = construct_base_samples_from_posterior(
posterior=posterior, sample_shape=sample_shape, qmc=qmc, seed=seed
)
self.assertEqual(samples.shape, expected_shape)
self.assertEqual(samples.device.type, self.device.type)
self.assertEqual(samples.dtype, dtype)
# multi-output, batch mode
mean = torch.zeros(2, 2, 2, device=self.device, dtype=dtype)
cov = torch.eye(4, device=self.device, dtype=dtype).expand(2, 4, 4)
mtmvn = MultitaskMultivariateNormal(mean=mean, covariance_matrix=cov)
posterior = GPyTorchPosterior(mvn=mtmvn)
for sample_shape, qmc, seed, collapse_batch_dims in itertools.product(
(torch.Size([5]), torch.Size([5, 3])),
(False, True),
(None, 1234),
(False, True),
):
if collapse_batch_dims:
expected_shape = sample_shape + torch.Size([1, 2, 2])
else:
expected_shape = sample_shape + torch.Size([2, 2, 2])
samples = construct_base_samples_from_posterior(
posterior=posterior,
sample_shape=sample_shape,
qmc=qmc,
collapse_batch_dims=collapse_batch_dims,
seed=seed,
)
self.assertEqual(samples.shape, expected_shape)
self.assertEqual(samples.device.type, self.device.type)
self.assertEqual(samples.dtype, dtype)
def test_GPyTorchPosterior(self):
for dtype in (torch.float, torch.double):
n = 3
mean = torch.rand(n, dtype=dtype, device=self.device)
variance = 1 + torch.rand(n, dtype=dtype, device=self.device)
covar = variance.diag()
mvn = MultivariateNormal(mean, lazify(covar))
posterior = GPyTorchPosterior(mvn=mvn)
# basics
self.assertEqual(posterior.device.type, self.device.type)
self.assertTrue(posterior.dtype == dtype)
self.assertEqual(posterior.event_shape, torch.Size([n, 1]))
self.assertTrue(torch.equal(posterior.mean, mean.unsqueeze(-1)))
self.assertTrue(
torch.equal(posterior.variance, variance.unsqueeze(-1)))
# rsample
samples = posterior.rsample()
self.assertEqual(samples.shape, torch.Size([1, n, 1]))
for sample_shape in ([4], [4, 2]):
samples = posterior.rsample(
sample_shape=torch.Size(sample_shape))
self.assertEqual(samples.shape,
torch.Size(sample_shape + [n, 1]))
# check enabling of approximate root decomposition
with ExitStack() as es:
mock_func = es.enter_context(
mock.patch(ROOT_DECOMP_PATH,
return_value=torch.cholesky(covar)))
es.enter_context(gpt_settings.max_cholesky_size(0))
es.enter_context(
gpt_settings.fast_computations(
covar_root_decomposition=True))
# need to clear cache, cannot re-use previous objects
mvn = MultivariateNormal(mean, lazify(covar))
posterior = GPyTorchPosterior(mvn=mvn)
posterior.rsample(sample_shape=torch.Size([4]))
mock_func.assert_called_once()
# rsample w/ base samples
base_samples = torch.randn(4,
3,
1,
device=self.device,
dtype=dtype)
# incompatible shapes
with self.assertRaises(RuntimeError):
posterior.rsample(sample_shape=torch.Size([3]),
base_samples=base_samples)
# ensure consistent result
for sample_shape in ([4], [4, 2]):
base_samples = torch.randn(*sample_shape,
3,
1,
device=self.device,
dtype=dtype)
samples = [
posterior.rsample(sample_shape=torch.Size(sample_shape),
base_samples=base_samples)
for _ in range(2)
]
self.assertTrue(torch.allclose(*samples))
# collapse_batch_dims
b_mean = torch.rand(2, 3, dtype=dtype, device=self.device)
b_variance = 1 + torch.rand(2, 3, dtype=dtype, device=self.device)
b_covar = torch.diag_embed(b_variance)
b_mvn = MultivariateNormal(b_mean, lazify(b_covar))
b_posterior = GPyTorchPosterior(mvn=b_mvn)
b_base_samples = torch.randn(4,
1,
3,
1,
device=self.device,
dtype=dtype)
b_samples = b_posterior.rsample(sample_shape=torch.Size([4]),
base_samples=b_base_samples)
self.assertEqual(b_samples.shape, torch.Size([4, 2, 3, 1]))
def test_GPyTorchPosterior(self, cuda=False):
device = torch.device("cuda") if cuda else torch.device("cpu")
for dtype in (torch.float, torch.double):
mean = torch.rand(3, dtype=dtype, device=device)
variance = 1 + torch.rand(3, dtype=dtype, device=device)
covar = variance.diag()
mvn = MultivariateNormal(mean, lazify(covar))
posterior = GPyTorchPosterior(mvn=mvn)
# basics
self.assertEqual(posterior.device.type, device.type)
self.assertTrue(posterior.dtype == dtype)
self.assertEqual(posterior.event_shape, torch.Size([3, 1]))
self.assertTrue(torch.equal(posterior.mean, mean.unsqueeze(-1)))
self.assertTrue(torch.equal(posterior.variance, variance.unsqueeze(-1)))
# rsample
samples = posterior.rsample()
self.assertEqual(samples.shape, torch.Size([1, 3, 1]))
samples = posterior.rsample(sample_shape=torch.Size([4]))
self.assertEqual(samples.shape, torch.Size([4, 3, 1]))
samples2 = posterior.rsample(sample_shape=torch.Size([4, 2]))
self.assertEqual(samples2.shape, torch.Size([4, 2, 3, 1]))
# rsample w/ base samples
base_samples = torch.randn(4, 3, 1, device=device, dtype=dtype)
# incompatible shapes
with self.assertRaises(RuntimeError):
posterior.rsample(
sample_shape=torch.Size([3]), base_samples=base_samples
)
samples_b1 = posterior.rsample(
sample_shape=torch.Size([4]), base_samples=base_samples
)
samples_b2 = posterior.rsample(
sample_shape=torch.Size([4]), base_samples=base_samples
)
self.assertTrue(torch.allclose(samples_b1, samples_b2))
base_samples2 = torch.randn(4, 2, 3, 1, device=device, dtype=dtype)
samples2_b1 = posterior.rsample(
sample_shape=torch.Size([4, 2]), base_samples=base_samples2
)
samples2_b2 = posterior.rsample(
sample_shape=torch.Size([4, 2]), base_samples=base_samples2
)
self.assertTrue(torch.allclose(samples2_b1, samples2_b2))
# collapse_batch_dims
b_mean = torch.rand(2, 3, dtype=dtype, device=device)
b_variance = 1 + torch.rand(2, 3, dtype=dtype, device=device)
b_covar = b_variance.unsqueeze(-1) * torch.eye(3).type_as(b_variance)
b_mvn = MultivariateNormal(b_mean, lazify(b_covar))
b_posterior = GPyTorchPosterior(mvn=b_mvn)
b_base_samples = torch.randn(4, 1, 3, 1, device=device, dtype=dtype)
b_samples = b_posterior.rsample(
sample_shape=torch.Size([4]), base_samples=b_base_samples
)
self.assertEqual(b_samples.shape, torch.Size([4, 2, 3, 1]))
def test_GPyTorchPosterior_Multitask(self):
for dtype in (torch.float, torch.double):
mean = torch.rand(3, 2, dtype=dtype, device=self.device)
variance = 1 + torch.rand(3, 2, dtype=dtype, device=self.device)
covar = variance.view(-1).diag()
mvn = MultitaskMultivariateNormal(mean, lazify(covar))
posterior = GPyTorchPosterior(mvn=mvn)
# basics
self.assertEqual(posterior.device.type, self.device.type)
self.assertTrue(posterior.dtype == dtype)
self.assertEqual(posterior.event_shape, torch.Size([3, 2]))
self.assertTrue(torch.equal(posterior.mean, mean))
self.assertTrue(torch.equal(posterior.variance, variance))
# rsample
samples = posterior.rsample(sample_shape=torch.Size([4]))
self.assertEqual(samples.shape, torch.Size([4, 3, 2]))
samples2 = posterior.rsample(sample_shape=torch.Size([4, 2]))
self.assertEqual(samples2.shape, torch.Size([4, 2, 3, 2]))
# rsample w/ base samples
base_samples = torch.randn(4,
3,
2,
device=self.device,
dtype=dtype)
samples_b1 = posterior.rsample(sample_shape=torch.Size([4]),
base_samples=base_samples)
samples_b2 = posterior.rsample(sample_shape=torch.Size([4]),
base_samples=base_samples)
self.assertTrue(torch.allclose(samples_b1, samples_b2))
base_samples2 = torch.randn(4,
2,
3,
2,
device=self.device,
dtype=dtype)
samples2_b1 = posterior.rsample(sample_shape=torch.Size([4, 2]),
base_samples=base_samples2)
samples2_b2 = posterior.rsample(sample_shape=torch.Size([4, 2]),
base_samples=base_samples2)
self.assertTrue(torch.allclose(samples2_b1, samples2_b2))
# collapse_batch_dims
b_mean = torch.rand(2, 3, 2, dtype=dtype, device=self.device)
b_variance = 1 + torch.rand(
2, 3, 2, dtype=dtype, device=self.device)
b_covar = torch.diag_embed(b_variance.view(2, 6))
b_mvn = MultitaskMultivariateNormal(b_mean, lazify(b_covar))
b_posterior = GPyTorchPosterior(mvn=b_mvn)
b_base_samples = torch.randn(4,
1,
3,
2,
device=self.device,
dtype=dtype)
b_samples = b_posterior.rsample(sample_shape=torch.Size([4]),
base_samples=b_base_samples)
self.assertEqual(b_samples.shape, torch.Size([4, 2, 3, 2]))
def test_degenerate_GPyTorchPosterior_Multitask(self):
for dtype in (torch.float, torch.double):
# singular covariance matrix
degenerate_covar = torch.tensor([[1, 1, 0], [1, 1, 0], [0, 0, 2]],
dtype=dtype,
device=self.device)
mean = torch.rand(3, dtype=dtype, device=self.device)
mvn = MultivariateNormal(mean, lazify(degenerate_covar))
mvn = MultitaskMultivariateNormal.from_independent_mvns([mvn, mvn])
posterior = GPyTorchPosterior(mvn=mvn)
# basics
self.assertEqual(posterior.device.type, self.device.type)
self.assertTrue(posterior.dtype == dtype)
self.assertEqual(posterior.event_shape, torch.Size([3, 2]))
mean_exp = mean.unsqueeze(-1).repeat(1, 2)
self.assertTrue(torch.equal(posterior.mean, mean_exp))
variance_exp = degenerate_covar.diag().unsqueeze(-1).repeat(1, 2)
self.assertTrue(torch.equal(posterior.variance, variance_exp))
# rsample
with warnings.catch_warnings(record=True) as w:
# we check that the p.d. warning is emitted - this only
# happens once per posterior, so we need to check only once
samples = posterior.rsample(sample_shape=torch.Size([4]))
self.assertEqual(len(w), 1)
self.assertTrue(issubclass(w[-1].category, RuntimeWarning))
self.assertTrue("not p.d." in str(w[-1].message))
self.assertEqual(samples.shape, torch.Size([4, 3, 2]))
samples2 = posterior.rsample(sample_shape=torch.Size([4, 2]))
self.assertEqual(samples2.shape, torch.Size([4, 2, 3, 2]))
# rsample w/ base samples
base_samples = torch.randn(4,
3,
2,
device=self.device,
dtype=dtype)
samples_b1 = posterior.rsample(sample_shape=torch.Size([4]),
base_samples=base_samples)
samples_b2 = posterior.rsample(sample_shape=torch.Size([4]),
base_samples=base_samples)
self.assertTrue(torch.allclose(samples_b1, samples_b2))
base_samples2 = torch.randn(4,
2,
3,
2,
device=self.device,
dtype=dtype)
samples2_b1 = posterior.rsample(sample_shape=torch.Size([4, 2]),
base_samples=base_samples2)
samples2_b2 = posterior.rsample(sample_shape=torch.Size([4, 2]),
base_samples=base_samples2)
self.assertTrue(torch.allclose(samples2_b1, samples2_b2))
# collapse_batch_dims
b_mean = torch.rand(2, 3, dtype=dtype, device=self.device)
b_degenerate_covar = degenerate_covar.expand(
2, *degenerate_covar.shape)
b_mvn = MultivariateNormal(b_mean, lazify(b_degenerate_covar))
b_mvn = MultitaskMultivariateNormal.from_independent_mvns(
[b_mvn, b_mvn])
b_posterior = GPyTorchPosterior(mvn=b_mvn)
b_base_samples = torch.randn(4,
1,
3,
2,
device=self.device,
dtype=dtype)
with warnings.catch_warnings(record=True) as w:
b_samples = b_posterior.rsample(sample_shape=torch.Size([4]),
base_samples=b_base_samples)
self.assertEqual(len(w), 1)
self.assertTrue(issubclass(w[-1].category, RuntimeWarning))
self.assertTrue("not p.d." in str(w[-1].message))
self.assertEqual(b_samples.shape, torch.Size([4, 2, 3, 2]))
def test_q_neg_int_post_variance(self):
no = "botorch.utils.testing.MockModel.num_outputs"
for dtype in (torch.float, torch.double):
# basic test
mean = torch.zeros(4, 1, device=self.device, dtype=dtype)
variance = torch.rand(4, 1, device=self.device, dtype=dtype)
mc_points = torch.rand(10, 1, device=self.device, dtype=dtype)
mfm = MockModel(MockPosterior(mean=mean, variance=variance))
with mock.patch.object(MockModel, "fantasize", return_value=mfm):
with mock.patch(
no,
new_callable=mock.PropertyMock) as mock_num_outputs:
mock_num_outputs.return_value = 1
# TODO: Make this work with arbitrary models
mm = MockModel(None)
qNIPV = qNegIntegratedPosteriorVariance(
model=mm, mc_points=mc_points)
X = torch.empty(1, 1, device=self.device,
dtype=dtype) # dummy
val = qNIPV(X)
self.assertTrue(
torch.allclose(val, -(variance.mean()), atol=1e-4))
# batched model
mean = torch.zeros(2, 4, 1, device=self.device, dtype=dtype)
variance = torch.rand(2, 4, 1, device=self.device, dtype=dtype)
mc_points = torch.rand(2, 10, 1, device=self.device, dtype=dtype)
mfm = MockModel(MockPosterior(mean=mean, variance=variance))
with mock.patch.object(MockModel, "fantasize", return_value=mfm):
with mock.patch(
no,
new_callable=mock.PropertyMock) as mock_num_outputs:
mock_num_outputs.return_value = 1
# TODO: Make this work with arbitrary models
mm = MockModel(None)
qNIPV = qNegIntegratedPosteriorVariance(
model=mm, mc_points=mc_points)
# TODO: Allow broadcasting for batch evaluation
X = torch.empty(2, 1, 1, device=self.device,
dtype=dtype) # dummy
val = qNIPV(X)
val_exp = -variance.mean(dim=-2).squeeze(-1)
self.assertTrue(torch.allclose(val, val_exp, atol=1e-4))
# multi-output model
mean = torch.zeros(4, 2, device=self.device, dtype=dtype)
variance = torch.rand(4, 2, device=self.device, dtype=dtype)
cov = torch.diag_embed(variance.view(-1))
f_posterior = GPyTorchPosterior(
MultitaskMultivariateNormal(mean, cov))
mc_points = torch.rand(10, 1, device=self.device, dtype=dtype)
mfm = MockModel(f_posterior)
with mock.patch.object(MockModel, "fantasize", return_value=mfm):
with mock.patch(
no,
new_callable=mock.PropertyMock) as mock_num_outputs:
mock_num_outputs.return_value = 2
mm = MockModel(None)
# check error if objective is not ScalarizedObjective
with self.assertRaises(UnsupportedError):
qNegIntegratedPosteriorVariance(
model=mm,
mc_points=mc_points,
objective=IdentityMCObjective(),
)
weights = torch.tensor([0.5, 0.5],
device=self.device,
dtype=dtype)
qNIPV = qNegIntegratedPosteriorVariance(
model=mm,
mc_points=mc_points,
objective=ScalarizedObjective(weights=weights),
)
X = torch.empty(1, 1, device=self.device,
dtype=dtype) # dummy
val = qNIPV(X)
self.assertTrue(
torch.allclose(val, -0.5 * variance.mean(), atol=1e-4))
# batched multi-output model
mean = torch.zeros(4, 3, 1, 2, device=self.device, dtype=dtype)
variance = torch.rand(4, 3, 1, 2, device=self.device, dtype=dtype)
cov = torch.diag_embed(variance.view(4, 3, -1))
f_posterior = GPyTorchPosterior(
MultitaskMultivariateNormal(mean, cov))
mc_points = torch.rand(4, 1, device=self.device, dtype=dtype)
mfm = MockModel(f_posterior)
with mock.patch.object(MockModel, "fantasize", return_value=mfm):
with mock.patch(
no,
new_callable=mock.PropertyMock) as mock_num_outputs:
mock_num_outputs.return_value = 2
mm = MockModel(None)
weights = torch.tensor([0.5, 0.5],
device=self.device,
dtype=dtype)
qNIPV = qNegIntegratedPosteriorVariance(
model=mm,
mc_points=mc_points,
objective=ScalarizedObjective(weights=weights),
)
X = torch.empty(3, 1, 1, device=self.device,
dtype=dtype) # dummy
val = qNIPV(X)
val_exp = -0.5 * variance.mean(dim=0).view(3,
-1).mean(dim=-1)
self.assertTrue(torch.allclose(val, val_exp, atol=1e-4))
def test_GPyTorchPosterior(self):
for dtype in (torch.float, torch.double):
mean = torch.rand(3, dtype=dtype, device=self.device)
variance = 1 + torch.rand(3, dtype=dtype, device=self.device)
covar = variance.diag()
mvn = MultivariateNormal(mean, lazify(covar))
posterior = GPyTorchPosterior(mvn=mvn)
# basics
self.assertEqual(posterior.device.type, self.device.type)
self.assertTrue(posterior.dtype == dtype)
self.assertEqual(posterior.event_shape, torch.Size([3, 1]))
self.assertTrue(torch.equal(posterior.mean, mean.unsqueeze(-1)))
self.assertTrue(
torch.equal(posterior.variance, variance.unsqueeze(-1)))
# rsample
samples = posterior.rsample()
self.assertEqual(samples.shape, torch.Size([1, 3, 1]))
samples = posterior.rsample(sample_shape=torch.Size([4]))
self.assertEqual(samples.shape, torch.Size([4, 3, 1]))
samples2 = posterior.rsample(sample_shape=torch.Size([4, 2]))
self.assertEqual(samples2.shape, torch.Size([4, 2, 3, 1]))
# rsample w/ base samples
base_samples = torch.randn(4,
3,
1,
device=self.device,
dtype=dtype)
# incompatible shapes
with self.assertRaises(RuntimeError):
posterior.rsample(sample_shape=torch.Size([3]),
base_samples=base_samples)
samples_b1 = posterior.rsample(sample_shape=torch.Size([4]),
base_samples=base_samples)
samples_b2 = posterior.rsample(sample_shape=torch.Size([4]),
base_samples=base_samples)
self.assertTrue(torch.allclose(samples_b1, samples_b2))
base_samples2 = torch.randn(4,
2,
3,
1,
device=self.device,
dtype=dtype)
samples2_b1 = posterior.rsample(sample_shape=torch.Size([4, 2]),
base_samples=base_samples2)
samples2_b2 = posterior.rsample(sample_shape=torch.Size([4, 2]),
base_samples=base_samples2)
self.assertTrue(torch.allclose(samples2_b1, samples2_b2))
# collapse_batch_dims
b_mean = torch.rand(2, 3, dtype=dtype, device=self.device)
b_variance = 1 + torch.rand(2, 3, dtype=dtype, device=self.device)
b_covar = torch.diag_embed(b_variance)
b_mvn = MultivariateNormal(b_mean, lazify(b_covar))
b_posterior = GPyTorchPosterior(mvn=b_mvn)
b_base_samples = torch.randn(4,
1,
3,
1,
device=self.device,
dtype=dtype)
b_samples = b_posterior.rsample(sample_shape=torch.Size([4]),
base_samples=b_base_samples)
self.assertEqual(b_samples.shape, torch.Size([4, 2, 3, 1]))
def posterior(
self,
X: Tensor,
output_indices: Optional[List[int]] = None,
observation_noise: Union[bool, Tensor] = False,
**kwargs: Any,
) -> GPyTorchPosterior:
r"""Computes the posterior over model outputs at the provided points.
Args:
X: A `(batch_shape) x q x d`-dim Tensor, where `d` is the dimension
of the feature space and `q` is the number of points considered
jointly.
output_indices: A list of indices, corresponding to the outputs over
which to compute the posterior (if the model is multi-output).
Can be used to speed up computation if only a subset of the
model's outputs are required for optimization. If omitted,
computes the posterior over all model outputs.
observation_noise: If True, add the observation noise from the
likelihood to the posterior. If a Tensor, use it directly as the
observation noise (must be of shape `(batch_shape) x q x m`).
Returns:
A `GPyTorchPosterior` object, representing `batch_shape` joint
distributions over `q` points and the outputs selected by
`output_indices` each. Includes observation noise if specified.
"""
self.eval() # make sure model is in eval mode
with gpt_posterior_settings():
# insert a dimension for the output dimension
if self._num_outputs > 1:
X, output_dim_idx = add_output_dim(
X=X, original_batch_shape=self._input_batch_shape)
mvn = self(X)
if observation_noise is not False:
if torch.is_tensor(observation_noise):
# TODO: Validate noise shape
# make observation_noise `batch_shape x q x n`
obs_noise = observation_noise.transpose(-1, -2)
mvn = self.likelihood(mvn, X, noise=obs_noise)
elif isinstance(self.likelihood, FixedNoiseGaussianLikelihood):
# Use the mean of the previous noise values (TODO: be smarter here).
noise = self.likelihood.noise.mean().expand(X.shape[:-1])
mvn = self.likelihood(mvn, X, noise=noise)
else:
mvn = self.likelihood(mvn, X)
if self._num_outputs > 1:
mean_x = mvn.mean
covar_x = mvn.covariance_matrix
output_indices = output_indices or range(self._num_outputs)
mvns = [
MultivariateNormal(
mean_x.select(dim=output_dim_idx, index=t),
lazify(covar_x.select(dim=output_dim_idx, index=t)),
) for t in output_indices
]
mvn = MultitaskMultivariateNormal.from_independent_mvns(
mvns=mvns)
posterior = GPyTorchPosterior(mvn=mvn)
if hasattr(self, "outcome_transform"):
posterior = self.outcome_transform.untransform_posterior(posterior)
return posterior
def posterior(
self,
X: Tensor,
output_indices: Optional[List[int]] = None,
observation_noise: Union[bool, Tensor] = False,
**kwargs: Any,
) -> GPyTorchPosterior:
r"""Computes the posterior over model outputs at the provided points.
Args:
X: A `b x q x d`-dim Tensor, where `d` is the dimension of the
feature space, `q` is the number of points considered jointly,
and `b` is the batch dimension.
output_indices: A list of indices, corresponding to the outputs over
which to compute the posterior (if the model is multi-output).
Can be used to speed up computation if only a subset of the
model's outputs are required for optimization. If omitted,
computes the posterior over all model outputs.
observation_noise: If True, add the observation noise from the
respective likelihoods to the posterior. If a Tensor of shape
`(batch_shape) x q x m`, use it directly as the observation
noise (with `observation_noise[...,i]` added to the posterior
of the `i`-th model).
Returns:
A `GPyTorchPosterior` object, representing `batch_shape` joint
distributions over `q` points and the outputs selected by
`output_indices` each. Includes measurement noise if
`observation_noise` is specified.
"""
self.eval() # make sure model is in eval mode
mvn_gen: Iterator
with gpt_posterior_settings():
# only compute what's necessary
if output_indices is not None:
mvns = [self.forward_i(i, X) for i in output_indices]
if observation_noise is not False:
if torch.is_tensor(observation_noise):
lh_kwargs = [{
"noise": observation_noise[..., i]
} for i, lh in enumerate(self.likelihood.likelihoods)]
else:
lh_kwargs = [
{
"noise": lh.noise.mean().expand(X.shape[:-1])
} if isinstance(
lh, FixedNoiseGaussianLikelihood) else {}
for lh in self.likelihood.likelihoods
]
mvns = [
self.likelihood_i(i, mvn, X,
**lkws) for i, mvn, lkws in zip(
output_indices, mvns, lh_kwargs)
]
mvn_gen = zip(output_indices, mvns)
else:
mvns = self(*[X for _ in range(self.num_outputs)])
if observation_noise is not False:
if torch.is_tensor(observation_noise):
mvns = self.likelihood(*[(mvn, X) for mvn in mvns],
noise=observation_noise)
else:
mvns = self.likelihood(*[(mvn, X) for mvn in mvns])
mvn_gen = enumerate(mvns)
# apply output transforms of individual models if present
mvns = []
for i, mvn in mvn_gen:
try:
oct = self.models[i].outcome_transform
tf_mvn = oct.untransform_posterior(GPyTorchPosterior(mvn)).mvn
except AttributeError:
tf_mvn = mvn
mvns.append(tf_mvn)
# return result as a GPyTorchPosteriors
if len(mvns) == 1:
return GPyTorchPosterior(mvn=mvns[0])
return GPyTorchPosterior(
mvn=MultitaskMultivariateNormal.from_independent_mvns(mvns=mvns))