def make_and_optimize_acqf(
override_qmc: bool = False) -> Tuple[Tensor, Tensor]:
add_kwargs = {"qmc": False} if override_qmc else {}
acquisition_function = self.acqf_constructor( # pyre-ignore: [28]
model=model,
objective_weights=objective_weights,
outcome_constraints=outcome_constraints,
X_observed=X_observed,
X_pending=X_pending,
**acf_options,
**add_kwargs,
)
acquisition_function = checked_cast(AcquisitionFunction,
acquisition_function)
# pyre-ignore: [28]
candidates, expected_acquisition_value = self.acqf_optimizer(
acq_function=checked_cast(AcquisitionFunction,
acquisition_function),
bounds=bounds_,
n=n,
inequality_constraints=_to_inequality_constraints(
linear_constraints=linear_constraints),
fixed_features=fixed_features,
rounding_func=botorch_rounding_func,
**optimizer_options,
)
return candidates, expected_acquisition_value
def gen(
self,
n: int,
bounds: List[Tuple[float, float]],
objective_weights: Tensor,
objective_thresholds: Optional[Tensor] = None,
outcome_constraints: Optional[Tuple[Tensor, Tensor]] = None,
linear_constraints: Optional[Tuple[Tensor, Tensor]] = None,
fixed_features: Optional[Dict[int, float]] = None,
pending_observations: Optional[List[Tensor]] = None,
model_gen_options: Optional[TConfig] = None,
rounding_func: Optional[Callable[[Tensor], Tensor]] = None,
target_fidelities: Optional[Dict[int, float]] = None,
) -> Tuple[Tensor, Tensor, TGenMetadata,
Optional[List[TCandidateMetadata]]]:
if self._search_space_digest is None:
raise RuntimeError("Must `fit` the model before calling `gen`.")
acq_options, opt_options = construct_acquisition_and_optimizer_options(
acqf_options=self.acquisition_options,
model_gen_options=model_gen_options)
# update bounds / target fidelities
new_ssd_args = {
**dataclasses.asdict(self._search_space_digest),
"bounds": bounds,
"target_fidelities": target_fidelities or {},
}
search_space_digest = SearchSpaceDigest(**new_ssd_args)
acqf = self._instantiate_acquisition(
search_space_digest=search_space_digest,
objective_weights=objective_weights,
objective_thresholds=objective_thresholds,
outcome_constraints=outcome_constraints,
linear_constraints=linear_constraints,
fixed_features=fixed_features,
pending_observations=pending_observations,
acq_options=acq_options,
)
botorch_rounding_func = get_rounding_func(rounding_func)
candidates, expected_acquisition_value = acqf.optimize(
n=n,
search_space_digest=search_space_digest,
inequality_constraints=_to_inequality_constraints(
linear_constraints=linear_constraints),
fixed_features=fixed_features,
rounding_func=botorch_rounding_func,
optimizer_options=checked_cast(dict, opt_options),
)
gen_metadata: TGenMetadata = {
Keys.EXPECTED_ACQF_VAL: expected_acquisition_value.tolist()
}
if objective_weights.nonzero().numel() > 1:
gen_metadata["objective_thresholds"] = acqf.objective_thresholds
gen_metadata["objective_weights"] = acqf.objective_weights
return (
candidates.detach().cpu(),
torch.ones(n, dtype=self.surrogate.dtype),
gen_metadata,
None,
)
def best_out_of_sample_point(
self,
bounds: List[Tuple[float, float]],
objective_weights: Tensor,
outcome_constraints: Optional[Tuple[Tensor, Tensor]] = None,
linear_constraints: Optional[Tuple[Tensor, Tensor]] = None,
fixed_features: Optional[Dict[int, float]] = None,
fidelity_features: Optional[List[int]] = None,
target_fidelities: Optional[Dict[int, float]] = None,
options: Optional[TConfig] = None,
) -> Tuple[Tensor, Tensor]:
"""Finds the best predicted point and the corresponding value of the
appropriate best point acquisition function.
"""
if fixed_features:
# When have fixed features, need `FixedFeatureAcquisitionFunction`
# which has peculiar instantiation (wraps another acquisition fn.),
# so need to figure out how to handle.
# TODO (ref: https://fburl.com/diff/uneqb3n9)
raise NotImplementedError("Fixed features not yet supported.")
options = options or {}
acqf_class, acqf_options = pick_best_out_of_sample_point_acqf_class(
outcome_constraints=outcome_constraints,
seed_inner=checked_cast_optional(int, options.get(Keys.SEED_INNER, None)),
qmc=checked_cast(bool, options.get(Keys.QMC, True)),
)
# Avoiding circular import between `Surrogate` and `Acquisition`.
from ax.models.torch.botorch_modular.acquisition import Acquisition
acqf = Acquisition( # TODO: For multi-fidelity, might need diff. class.
surrogate=self,
botorch_acqf_class=acqf_class,
bounds=bounds,
objective_weights=objective_weights,
outcome_constraints=outcome_constraints,
linear_constraints=linear_constraints,
fixed_features=fixed_features,
target_fidelities=target_fidelities,
options=acqf_options,
)
candidates, acqf_values = acqf.optimize(
# pyre-ignore[6]: Exp. Tensor, got List[Tuple[float, float]].
# TODO: Fix typing of `bounds` in `TorchModel`-s.
bounds=bounds,
n=1,
inequality_constraints=_to_inequality_constraints(
linear_constraints=linear_constraints
),
fixed_features=fixed_features,
)
return candidates[0], acqf_values[0]
def gen(
self,
n: int,
bounds: List[Tuple[float, float]],
objective_weights: Tensor,
objective_thresholds: Optional[Tensor] = None,
outcome_constraints: Optional[Tuple[Tensor, Tensor]] = None,
linear_constraints: Optional[Tuple[Tensor, Tensor]] = None,
fixed_features: Optional[Dict[int, float]] = None,
pending_observations: Optional[List[Tensor]] = None,
model_gen_options: Optional[TConfig] = None,
rounding_func: Optional[Callable[[Tensor], Tensor]] = None,
target_fidelities: Optional[Dict[int, float]] = None,
) -> Tuple[Tensor, Tensor, TGenMetadata,
Optional[List[TCandidateMetadata]]]:
acq_options, opt_options = construct_acquisition_and_optimizer_options(
acqf_options=self.acquisition_options,
model_gen_options=model_gen_options)
acqf = self._instantiate_acquisition(
bounds=bounds,
objective_weights=objective_weights,
objective_thresholds=objective_thresholds,
outcome_constraints=outcome_constraints,
linear_constraints=linear_constraints,
fixed_features=fixed_features,
pending_observations=pending_observations,
target_fidelities=target_fidelities,
acq_options=acq_options,
)
botorch_rounding_func = get_rounding_func(rounding_func)
candidates, expected_acquisition_value = acqf.optimize(
bounds=self._bounds_as_tensor(bounds=bounds),
n=n,
inequality_constraints=_to_inequality_constraints(
linear_constraints=linear_constraints),
fixed_features=fixed_features,
rounding_func=botorch_rounding_func,
optimizer_options=checked_cast(dict, opt_options),
)
return (
candidates.detach().cpu(),
torch.ones(n, dtype=self.surrogate.dtype),
{
Keys.EXPECTED_ACQF_VAL: expected_acquisition_value.tolist()
},
None,
)
def gen(
self,
n: int,
bounds: List,
objective_weights: Tensor,
outcome_constraints: Optional[Tuple[Tensor, Tensor]] = None,
linear_constraints: Optional[Tuple[Tensor, Tensor]] = None,
fixed_features: Optional[Dict[int, float]] = None,
pending_observations: Optional[List[Tensor]] = None,
model_gen_options: Optional[TConfig] = None,
rounding_func: Optional[Callable[[Tensor], Tensor]] = None,
target_fidelities: Optional[Dict[int, float]] = None,
) -> Tuple[Tensor, Tensor, TGenMetadata,
Optional[List[TCandidateMetadata]]]:
r"""Generate new candidates.
Args:
n: Number of candidates to generate.
bounds: A list of (lower, upper) tuples for each column of X.
objective_weights: The objective is to maximize a weighted sum of
the columns of f(x). These are the weights.
outcome_constraints: A tuple of (A, b). For k outcome constraints
and m outputs at f(x), A is (k x m) and b is (k x 1) such that
A f(x) <= b.
linear_constraints: A tuple of (A, b). For k linear constraints on
d-dimensional x, A is (k x d) and b is (k x 1) such that
A x <= b.
fixed_features: A map {feature_index: value} for features that
should be fixed to a particular value during generation.
pending_observations: A list of m (k_i x d) feature tensors X
for m outcomes and k_i pending observations for outcome i.
model_gen_options: A config dictionary that can contain
model-specific options.
rounding_func: A function that rounds an optimization result
appropriately (i.e., according to `round-trip` transformations).
target_fidelities: A map {feature_index: value} of fidelity feature
column indices to their respective target fidelities. Used for
multi-fidelity optimization.
Returns:
3-element tuple containing
- (n x d) tensor of generated points.
- n-tensor of weights for each point.
- Dictionary of model-specific metadata for the given
generation candidates.
"""
options = model_gen_options or {}
acf_options = options.get("acquisition_function_kwargs", {})
optimizer_options = options.get("optimizer_kwargs", {})
X_pending, X_observed = _get_X_pending_and_observed(
Xs=self.Xs,
pending_observations=pending_observations,
objective_weights=objective_weights,
outcome_constraints=outcome_constraints,
bounds=bounds,
linear_constraints=linear_constraints,
fixed_features=fixed_features,
)
# subset model only to the outcomes we need for the optimization
model = not_none(self.model)
if options.get("subset_model", True):
model, objective_weights, outcome_constraints, _ = subset_model(
model=model,
objective_weights=objective_weights,
outcome_constraints=outcome_constraints,
)
objective = get_botorch_objective(
model=model,
objective_weights=objective_weights,
outcome_constraints=outcome_constraints,
X_observed=X_observed,
)
inequality_constraints = _to_inequality_constraints(linear_constraints)
# TODO: update optimizers to handle inequality_constraints
if inequality_constraints is not None:
raise UnsupportedError(
"Inequality constraints are not yet supported for KnowledgeGradient!"
)
# extract a few options
n_fantasies = acf_options.get("num_fantasies", 64)
qmc = acf_options.get("qmc", True)
seed_inner = acf_options.get("seed_inner", None)
num_restarts = optimizer_options.get("num_restarts", 40)
raw_samples = optimizer_options.get("raw_samples", 1024)
# get current value
current_value = self._get_current_value(
model=model,
bounds=bounds,
X_observed=not_none(X_observed),
objective_weights=objective_weights,
outcome_constraints=outcome_constraints,
linear_constraints=linear_constraints,
seed_inner=seed_inner,
fixed_features=fixed_features,
model_gen_options=model_gen_options,
target_fidelities=target_fidelities,
qmc=qmc,
)
bounds_ = torch.tensor(bounds, dtype=self.dtype, device=self.device)
bounds_ = bounds_.transpose(0, 1)
# get acquisition function
acq_function = _instantiate_KG(
model=model,
objective=objective,
qmc=qmc,
n_fantasies=n_fantasies,
num_trace_observations=options.get("num_trace_observations", 0),
mc_samples=acf_options.get("mc_samples", 256),
seed_inner=seed_inner,
seed_outer=acf_options.get("seed_outer", None),
X_pending=X_pending,
target_fidelities=target_fidelities,
fidelity_weights=options.get("fidelity_weights"),
current_value=current_value,
cost_intercept=self.cost_intercept,
)
# optimize and get new points
new_x = _optimize_and_get_candidates(
acq_function=acq_function,
bounds_=bounds_,
n=n,
num_restarts=num_restarts,
raw_samples=raw_samples,
optimizer_options=optimizer_options,
rounding_func=rounding_func,
inequality_constraints=inequality_constraints,
fixed_features=fixed_features,
)
return new_x, torch.ones(n, dtype=self.dtype), {}, None
def gen(
self,
n: int,
bounds: List[Tuple[float, float]],
objective_weights: Tensor, # objective_directions
outcome_constraints: Optional[Tuple[Tensor, Tensor]] = None,
objective_thresholds: Optional[Tensor] = None,
linear_constraints: Optional[Tuple[Tensor, Tensor]] = None,
fixed_features: Optional[Dict[int, float]] = None,
pending_observations: Optional[List[Tensor]] = None,
model_gen_options: Optional[TConfig] = None,
rounding_func: Optional[Callable[[Tensor], Tensor]] = None,
target_fidelities: Optional[Dict[int, float]] = None,
) -> Tuple[Tensor, Tensor, TGenMetadata,
Optional[List[TCandidateMetadata]]]:
options = model_gen_options or {}
acf_options = options.get("acquisition_function_kwargs", {})
optimizer_options = options.get("optimizer_kwargs", {})
if target_fidelities:
raise NotImplementedError(
"target_fidelities not implemented for base BotorchModel")
X_pending, X_observed = _get_X_pending_and_observed(
Xs=self.Xs,
pending_observations=pending_observations,
objective_weights=objective_weights,
outcome_constraints=outcome_constraints,
bounds=bounds,
linear_constraints=linear_constraints,
fixed_features=fixed_features,
)
model = self.model
# subset model only to the outcomes we need for the optimization
if options.get(Keys.SUBSET_MODEL, True):
model, objective_weights, outcome_constraints, Ys = subset_model(
model=model, # pyre-ignore [6]
objective_weights=objective_weights,
outcome_constraints=outcome_constraints,
Ys=self.Ys,
)
else:
Ys = self.Ys
bounds_ = torch.tensor(bounds, dtype=self.dtype, device=self.device)
bounds_ = bounds_.transpose(0, 1)
botorch_rounding_func = get_rounding_func(rounding_func)
if acf_options.get("random_scalarization", False) or acf_options.get(
"chebyshev_scalarization", False):
# If using a list of acquisition functions, the algorithm to generate
# that list is configured by acquisition_function_kwargs.
objective_weights_list = [
randomize_objective_weights(objective_weights, **acf_options)
for _ in range(n)
]
acquisition_function_list = [
self.acqf_constructor( # pyre-ignore: [28]
model=model,
objective_weights=objective_weights,
outcome_constraints=outcome_constraints,
X_observed=X_observed,
X_pending=X_pending,
Ys=Ys, # Required for chebyshev scalarization calculations.
**acf_options,
) for objective_weights in objective_weights_list
]
acquisition_function_list = [
checked_cast(AcquisitionFunction, acq_function)
for acq_function in acquisition_function_list
]
# Multiple acquisition functions require a sequential optimizer
# always use scipy_optimizer_list.
# TODO(jej): Allow any optimizer.
candidates, expected_acquisition_value = scipy_optimizer_list(
acq_function_list=acquisition_function_list,
bounds=bounds_,
inequality_constraints=_to_inequality_constraints(
linear_constraints=linear_constraints),
fixed_features=fixed_features,
rounding_func=botorch_rounding_func,
**optimizer_options,
)
else:
acquisition_function = self.acqf_constructor( # pyre-ignore: [28]
model=model,
objective_weights=objective_weights,
objective_thresholds=objective_thresholds,
outcome_constraints=outcome_constraints,
X_observed=X_observed,
X_pending=X_pending,
Ys=self.Ys, # Required for qEHVI calculations.
**acf_options,
)
acquisition_function = checked_cast(AcquisitionFunction,
acquisition_function)
# pyre-ignore: [28]
candidates, expected_acquisition_value = self.acqf_optimizer(
acq_function=checked_cast(AcquisitionFunction,
acquisition_function),
bounds=bounds_,
n=n,
inequality_constraints=_to_inequality_constraints(
linear_constraints=linear_constraints),
fixed_features=fixed_features,
rounding_func=botorch_rounding_func,
**optimizer_options,
)
return (
candidates.detach().cpu(),
torch.ones(n, dtype=self.dtype),
{
"expected_acquisition_value":
expected_acquisition_value.tolist()
},
None,
)
def gen(
self,
n: int,
bounds: List[Tuple[float, float]],
objective_weights: Tensor,
outcome_constraints: Optional[Tuple[Tensor, Tensor]] = None,
linear_constraints: Optional[Tuple[Tensor, Tensor]] = None,
fixed_features: Optional[Dict[int, float]] = None,
pending_observations: Optional[List[Tensor]] = None,
model_gen_options: Optional[TConfig] = None,
rounding_func: Optional[Callable[[Tensor], Tensor]] = None,
target_fidelities: Optional[Dict[int, float]] = None,
) -> Tuple[Tensor, Tensor, TGenMetadata, Optional[List[TCandidateMetadata]]]:
options = model_gen_options or {}
acf_options = options.get(Keys.ACQF_KWARGS, {})
optimizer_options = options.get(Keys.OPTIMIZER_KWARGS, {})
if target_fidelities:
raise NotImplementedError(
"target_fidelities not implemented for base BotorchModel"
)
X_pending, X_observed = _get_X_pending_and_observed(
Xs=self.Xs,
pending_observations=pending_observations,
objective_weights=objective_weights,
outcome_constraints=outcome_constraints,
bounds=bounds,
linear_constraints=linear_constraints,
fixed_features=fixed_features,
)
model = self.model
# subset model only to the outcomes we need for the optimization 357
if options.get(Keys.SUBSET_MODEL, True):
model, objective_weights, outcome_constraints, _ = subset_model(
model=model, # pyre-ignore [6]
objective_weights=objective_weights,
outcome_constraints=outcome_constraints,
)
bounds_ = torch.tensor(bounds, dtype=self.dtype, device=self.device)
bounds_ = bounds_.transpose(0, 1)
botorch_rounding_func = get_rounding_func(rounding_func)
acquisition_function = self.acqf_constructor( # pyre-ignore: [28]
model=model,
objective_weights=objective_weights,
outcome_constraints=outcome_constraints,
X_observed=X_observed,
X_pending=X_pending,
**acf_options,
)
acquisition_function = checked_cast(AcquisitionFunction, acquisition_function)
# pyre-ignore: [28]
candidates, expected_acquisition_value = self.acqf_optimizer(
acq_function=checked_cast(AcquisitionFunction, acquisition_function),
bounds=bounds_,
n=n,
inequality_constraints=_to_inequality_constraints(
linear_constraints=linear_constraints
),
fixed_features=fixed_features,
rounding_func=botorch_rounding_func,
**optimizer_options,
)
return (
candidates.detach().cpu(),
torch.ones(n, dtype=self.dtype),
{"expected_acquisition_value": expected_acquisition_value.tolist()},
None,
)
def recommend_best_out_of_sample_point(
model: TorchModel,
bounds: List[Tuple[float, float]],
objective_weights: Tensor,
outcome_constraints: Optional[Tuple[Tensor, Tensor]] = None,
linear_constraints: Optional[Tuple[Tensor, Tensor]] = None,
fixed_features: Optional[Dict[int, float]] = None,
model_gen_options: Optional[TConfig] = None,
target_fidelities: Optional[Dict[int, float]] = None,
) -> Optional[Tensor]:
"""
Identify the current best point by optimizing the posterior mean of the model.
This is "out-of-sample" because it considers un-observed designs as well.
Return None if no such point can be identified.
Args:
model: A TorchModel.
bounds: A list of (lower, upper) tuples for each column of X.
objective_weights: The objective is to maximize a weighted sum of
the columns of f(x). These are the weights.
outcome_constraints: A tuple of (A, b). For k outcome constraints
and m outputs at f(x), A is (k x m) and b is (k x 1) such that
A f(x) <= b.
linear_constraints: A tuple of (A, b). For k linear constraints on
d-dimensional x, A is (k x d) and b is (k x 1) such that
A x <= b.
fixed_features: A map {feature_index: value} for features that
should be fixed to a particular value in the best point.
model_gen_options: A config dictionary that can contain
model-specific options.
target_fidelities: A map {feature_index: value} of fidelity feature
column indices to their respective target fidelities. Used for
multi-fidelity optimization.
Returns:
A d-array of the best point, or None if no feasible point exists.
"""
options = model_gen_options or {}
fixed_features = fixed_features or {}
acf_options = options.get("acquisition_function_kwargs", {})
optimizer_options = options.get("optimizer_kwargs", {})
X_observed = get_observed(
Xs=model.Xs, # pyre-ignore: [16]
objective_weights=objective_weights,
outcome_constraints=outcome_constraints,
)
if hasattr(model, "_get_best_point_acqf"):
acq_function, non_fixed_idcs = model._get_best_point_acqf( # pyre-ignore: [16]
X_observed=X_observed,
objective_weights=objective_weights,
mc_samples=acf_options.get("mc_samples", 512),
fixed_features=fixed_features,
target_fidelities=target_fidelities,
outcome_constraints=outcome_constraints,
seed_inner=acf_options.get("seed_inner", None),
qmc=acf_options.get("qmc", True),
)
else:
raise RuntimeError("The model should implement _get_best_point_acqf.")
inequality_constraints = _to_inequality_constraints(linear_constraints)
# TODO: update optimizers to handle inequality_constraints
# (including transforming constraints b/c of fixed features)
if inequality_constraints is not None:
raise UnsupportedError("Inequality constraints are not supported!")
return_best_only = optimizer_options.get("return_best_only", True)
bounds_ = torch.tensor(bounds, dtype=model.dtype, device=model.device)
bounds_ = bounds_.transpose(-1, -2)
if non_fixed_idcs is not None:
bounds_ = bounds_[..., non_fixed_idcs]
candidates, _ = optimize_acqf(
acq_function=acq_function,
bounds=bounds_,
q=1,
num_restarts=optimizer_options.get("num_restarts", 60),
raw_samples=optimizer_options.get("raw_samples", 1024),
inequality_constraints=inequality_constraints,
fixed_features=None, # handled inside the acquisition function
options={
"batch_limit": optimizer_options.get("batch_limit", 8),
"maxiter": optimizer_options.get("maxiter", 200),
"nonnegative": optimizer_options.get("nonnegative", False),
"method": "L-BFGS-B",
},
return_best_only=return_best_only,
)
rec_point = candidates.detach().cpu()
if isinstance(acq_function, FixedFeatureAcquisitionFunction):
rec_point = acq_function._construct_X_full(rec_point)
if return_best_only:
rec_point = rec_point.view(-1)
return rec_point
def gen(
self,
n: int,
bounds: List[Tuple[float, float]],
objective_weights: Tensor, # objective_directions
outcome_constraints: Optional[Tuple[Tensor, Tensor]] = None,
objective_thresholds: Optional[Tensor] = None,
linear_constraints: Optional[Tuple[Tensor, Tensor]] = None,
fixed_features: Optional[Dict[int, float]] = None,
pending_observations: Optional[List[Tensor]] = None,
model_gen_options: Optional[TConfig] = None,
rounding_func: Optional[Callable[[Tensor], Tensor]] = None,
target_fidelities: Optional[Dict[int, float]] = None,
) -> Tuple[Tensor, Tensor, TGenMetadata,
Optional[List[TCandidateMetadata]]]:
options = model_gen_options or {}
acf_options = options.get("acquisition_function_kwargs", {})
optimizer_options = options.get("optimizer_kwargs", {})
if target_fidelities:
raise NotImplementedError(
"target_fidelities not implemented for base BotorchModel")
if (objective_thresholds is not None and
objective_weights.shape[0] != objective_thresholds.shape[0]):
raise AxError(
"Objective weights and thresholds most both contain an element for"
" each modeled metric.")
X_pending, X_observed = _get_X_pending_and_observed(
Xs=self.Xs,
pending_observations=pending_observations,
objective_weights=objective_weights,
outcome_constraints=outcome_constraints,
bounds=bounds,
linear_constraints=linear_constraints,
fixed_features=fixed_features,
)
model = not_none(self.model)
full_objective_thresholds = objective_thresholds
full_objective_weights = objective_weights
full_outcome_constraints = outcome_constraints
# subset model only to the outcomes we need for the optimization
if options.get(Keys.SUBSET_MODEL, True):
full_objective_weights
subset_model_results = subset_model(
model=model,
objective_weights=objective_weights,
outcome_constraints=outcome_constraints,
objective_thresholds=objective_thresholds,
)
model = subset_model_results.model
objective_weights = subset_model_results.objective_weights
outcome_constraints = subset_model_results.outcome_constraints
objective_thresholds = subset_model_results.objective_thresholds
idcs = subset_model_results.indices
else:
idcs = None
if objective_thresholds is None:
full_objective_thresholds = infer_objective_thresholds(
model=model,
X_observed=not_none(X_observed),
objective_weights=full_objective_weights,
outcome_constraints=full_outcome_constraints,
subset_idcs=idcs,
)
# subset the objective thresholds
objective_thresholds = (full_objective_thresholds
if idcs is None else
full_objective_thresholds[idcs].clone())
bounds_ = torch.tensor(bounds, dtype=self.dtype, device=self.device)
bounds_ = bounds_.transpose(0, 1)
botorch_rounding_func = get_rounding_func(rounding_func)
if acf_options.get("random_scalarization", False) or acf_options.get(
"chebyshev_scalarization", False):
# If using a list of acquisition functions, the algorithm to generate
# that list is configured by acquisition_function_kwargs.
objective_weights_list = [
randomize_objective_weights(objective_weights, **acf_options)
for _ in range(n)
]
acquisition_function_list = [
self.acqf_constructor( # pyre-ignore: [28]
model=model,
objective_weights=objective_weights,
outcome_constraints=outcome_constraints,
X_observed=X_observed,
X_pending=X_pending,
**acf_options,
) for objective_weights in objective_weights_list
]
acquisition_function_list = [
checked_cast(AcquisitionFunction, acq_function)
for acq_function in acquisition_function_list
]
# Multiple acquisition functions require a sequential optimizer
# always use scipy_optimizer_list.
# TODO(jej): Allow any optimizer.
candidates, expected_acquisition_value = scipy_optimizer_list(
acq_function_list=acquisition_function_list,
bounds=bounds_,
inequality_constraints=_to_inequality_constraints(
linear_constraints=linear_constraints),
fixed_features=fixed_features,
rounding_func=botorch_rounding_func,
**optimizer_options,
)
else:
acquisition_function = self.acqf_constructor( # pyre-ignore: [28]
model=model,
objective_weights=objective_weights,
objective_thresholds=objective_thresholds,
outcome_constraints=outcome_constraints,
X_observed=X_observed,
X_pending=X_pending,
**acf_options,
)
acquisition_function = checked_cast(AcquisitionFunction,
acquisition_function)
# pyre-ignore: [28]
candidates, expected_acquisition_value = self.acqf_optimizer(
acq_function=checked_cast(AcquisitionFunction,
acquisition_function),
bounds=bounds_,
n=n,
inequality_constraints=_to_inequality_constraints(
linear_constraints=linear_constraints),
fixed_features=fixed_features,
rounding_func=botorch_rounding_func,
**optimizer_options,
)
gen_metadata = {
"expected_acquisition_value": expected_acquisition_value.tolist(),
"objective_thresholds": not_none(full_objective_thresholds).cpu(),
}
return (
candidates.detach().cpu(),
torch.ones(n, dtype=self.dtype),
gen_metadata,
None,
)
def gen(
self,
n: int,
bounds: List,
objective_weights: Tensor,
outcome_constraints: Optional[Tuple[Tensor, Tensor]] = None,
linear_constraints: Optional[Tuple[Tensor, Tensor]] = None,
fixed_features: Optional[Dict[int, float]] = None,
pending_observations: Optional[List[Tensor]] = None,
model_gen_options: Optional[TConfig] = None,
rounding_func: Optional[Callable[[Tensor], Tensor]] = None,
target_fidelities: Optional[Dict[int, float]] = None,
) -> Tuple[Tensor, Tensor, TGenMetadata]:
"""
Generate new candidates.
Args:
n: Number of candidates to generate.
bounds: A list of (lower, upper) tuples for each column of X.
objective_weights: The objective is to maximize a weighted sum of
the columns of f(x). These are the weights.
outcome_constraints: A tuple of (A, b). For k outcome constraints
and m outputs at f(x), A is (k x m) and b is (k x 1) such that
A f(x) <= b.
linear_constraints: A tuple of (A, b). For k linear constraints on
d-dimensional x, A is (k x d) and b is (k x 1) such that
A x <= b.
fixed_features: A map {feature_index: value} for features that
should be fixed to a particular value during generation.
pending_observations: A list of m (k_i x d) feature tensors X
for m outcomes and k_i pending observations for outcome i.
model_gen_options: A config dictionary that can contain
model-specific options.
rounding_func: A function that rounds an optimization result
appropriately (i.e., according to `round-trip` transformations).
target_fidelities: A map {feature_index: value} of fidelity feature
column indices to their respective target fidelities. Used for
multi-fidelity optimization.
Returns:
3-element tuple containing
- (n x d) tensor of generated points.
- n-tensor of weights for each point.
- Dictionary of model-specific metadata for the given
generation candidates.
"""
options = model_gen_options or {}
acf_options = options.get("acquisition_function_kwargs", {})
optimizer_options = options.get("optimizer_kwargs", {})
X_pending, X_observed = _get_X_pending_and_observed(
Xs=self.Xs,
pending_observations=pending_observations,
objective_weights=objective_weights,
outcome_constraints=outcome_constraints,
bounds=bounds,
linear_constraints=linear_constraints,
fixed_features=fixed_features,
)
model = self.model
# subset model only to the outcomes we need for the optimization
if options.get("subset_model", True):
model, objective_weights, outcome_constraints = subset_model(
model=model, # pyre-ignore [6]
objective_weights=objective_weights,
outcome_constraints=outcome_constraints,
)
objective = _get_objective(
model=model, # pyre-ignore [6]
objective_weights=objective_weights,
outcome_constraints=outcome_constraints,
X_observed=X_observed,
)
# get the acquisition function
n_fantasies = acf_options.get("num_fantasies", 64)
qmc = acf_options.get("qmc", True)
seed_inner = acf_options.get("seed_inner", None)
num_restarts = optimizer_options.get("num_restarts", 40)
raw_samples = optimizer_options.get("raw_samples", 1024)
inequality_constraints = _to_inequality_constraints(linear_constraints)
# TODO: update optimizers to handle inequality_constraints
if inequality_constraints is not None:
raise UnsupportedError(
"Inequality constraints are not yet supported for KnowledgeGradient!"
)
# get current value
best_point_acqf, non_fixed_idcs = self._get_best_point_acqf(
objective_weights=objective_weights,
outcome_constraints=outcome_constraints,
X_observed=X_observed, # pyre-ignore: [6]
seed_inner=seed_inner,
fixed_features=fixed_features,
target_fidelities=target_fidelities,
qmc=qmc,
)
# solution from previous iteration
recommended_point = self.best_point(
bounds=bounds,
objective_weights=objective_weights,
outcome_constraints=outcome_constraints,
linear_constraints=linear_constraints,
fixed_features=fixed_features,
model_gen_options=model_gen_options,
target_fidelities=target_fidelities,
)
recommended_point = recommended_point.detach().unsqueeze(
0) # pyre-ignore: [16]
# Extract acquisition value (TODO: Make this less painful and repetitive)
if non_fixed_idcs is not None:
recommended_point = recommended_point[..., non_fixed_idcs]
current_value = best_point_acqf(recommended_point).max()
acq_function = _instantiate_KG(
model=model, # pyre-ignore [6]
objective=objective,
qmc=qmc,
n_fantasies=n_fantasies,
num_trace_observations=options.get("num_trace_observations", 0),
mc_samples=acf_options.get("mc_samples", 256),
seed_inner=seed_inner,
seed_outer=acf_options.get("seed_outer", None),
X_pending=X_pending,
target_fidelities=target_fidelities,
fidelity_weights=options.get("fidelity_weights"),
current_value=current_value,
cost_intercept=self.cost_intercept,
)
# optimize and get new points
bounds_ = torch.tensor(bounds, dtype=self.dtype, device=self.device)
bounds_ = bounds_.transpose(0, 1)
batch_initial_conditions = gen_one_shot_kg_initial_conditions(
acq_function=acq_function,
bounds=bounds_,
q=n,
num_restarts=num_restarts,
raw_samples=raw_samples,
options={
"frac_random": optimizer_options.get("frac_random", 0.1),
"num_inner_restarts": num_restarts,
"raw_inner_samples": raw_samples,
},
)
botorch_rounding_func = get_rounding_func(rounding_func)
candidates, _ = optimize_acqf(
acq_function=acq_function,
bounds=bounds_,
q=n,
inequality_constraints=inequality_constraints,
fixed_features=fixed_features,
post_processing_func=botorch_rounding_func,
num_restarts=num_restarts,
raw_samples=raw_samples,
options={
"batch_limit": optimizer_options.get("batch_limit", 8),
"maxiter": optimizer_options.get("maxiter", 200),
"method": "L-BFGS-B",
"nonnegative": optimizer_options.get("nonnegative", False),
},
batch_initial_conditions=batch_initial_conditions,
)
new_x = candidates.detach().cpu()
return new_x, torch.ones(n, dtype=self.dtype), {}
