#!/usr/bin/env python3
# Copyright (c) Facebook, Inc. and its affiliates.
#
# This source code is licensed under the MIT license found in the
# LICENSE file in the root directory of this source tree.
# pyre-strict
from typing import Dict, List, Optional
from ax.core.arm import Arm
from ax.core.base import Base
from ax.core.parameter import FixedParameter, Parameter
from ax.core.parameter_constraint import (
OrderConstraint,
ParameterConstraint,
SumConstraint,
)
from ax.core.types import TParameterization
[docs]class SearchSpace(Base):
"""Base object for SearchSpace object.
Contains a set of Parameter objects, each of which have a
name, type, and set of valid values. The search space also contains
a set of ParameterConstraint objects, which can be used to define
restrictions across parameters (e.g. p_a < p_b).
"""
def __init__(
self,
parameters: List[Parameter],
parameter_constraints: Optional[List[ParameterConstraint]] = None,
) -> None:
"""Initialize SearchSpace
Args:
parameters: List of parameter objects for the search space.
parameter_constraints: List of parameter constraints.
"""
if len({p.name for p in parameters}) < len(parameters):
raise ValueError("Parameter names must be unique.")
self._parameters: Dict[str, Parameter] = {p.name: p for p in parameters}
self.set_parameter_constraints(parameter_constraints or [])
@property
def parameters(self) -> Dict[str, Parameter]:
return self._parameters
@property
def parameter_constraints(self) -> List[ParameterConstraint]:
return self._parameter_constraints
@property
def tunable_parameters(self) -> Dict[str, Parameter]:
return {
name: parameter
for name, parameter in self._parameters.items()
if not isinstance(parameter, FixedParameter)
}
[docs] def add_parameter_constraints(
self, parameter_constraints: List[ParameterConstraint]
) -> None:
self._validate_parameter_constraints(parameter_constraints)
self._parameter_constraints.extend(parameter_constraints)
[docs] def set_parameter_constraints(
self, parameter_constraints: List[ParameterConstraint]
) -> None:
self._validate_parameter_constraints(parameter_constraints)
self._parameter_constraints: List[ParameterConstraint] = parameter_constraints
[docs] def add_parameter(self, parameter: Parameter) -> None:
if parameter.name in self._parameters.keys():
raise ValueError(
f"Parameter `{parameter.name}` already exists in search space. "
"Use `update_parameter` to update an existing parameter."
)
self._parameters[parameter.name] = parameter
[docs] def update_parameter(self, parameter: Parameter) -> None:
if parameter.name not in self._parameters.keys():
raise ValueError(
f"Parameter `{parameter.name}` does not exist in search space. "
"Use `add_parameter` to add a new parameter."
)
prev_type = self._parameters[parameter.name].parameter_type
if parameter.parameter_type != prev_type:
raise ValueError(
f"Parameter `{parameter.name}` has type {prev_type.name}. "
f"Cannot update to type {parameter.parameter_type.name}."
)
self._parameters[parameter.name] = parameter
[docs] def check_membership(
self, parameterization: TParameterization, raise_error: bool = False
) -> bool:
"""Whether the given parameterization belongs in the search space.
Checks that the given parameter values have the same name/type as
search space parameters, are contained in the search space domain,
and satisfy the parameter constraints.
Args:
parameterization: Dict from parameter name to value to validate.
raise_error: If true parameterization does not belong, raises an error
with detailed explanation of why.
Returns:
Whether the parameterization is contained in the search space.
"""
if len(parameterization) != len(self._parameters):
if raise_error:
raise ValueError(
f"Parameterization has {len(parameterization)} parameters "
f"but search space has {len(self._parameters)}."
)
return False
for name, value in parameterization.items():
if name not in self._parameters:
if raise_error:
raise ValueError(f"Parameter {name} not defined in search space")
return False
if not self._parameters[name].validate(value):
if raise_error:
raise ValueError(
f"{value} is not a valid value for "
f"parameter {self._parameters[name]}"
)
return False
# parameter constraints only accept numeric parameters
numerical_param_dict = {
# pyre-fixme[6]: Expected `typing.Union[...oat]` but got `unknown`.
name: float(value)
for name, value in parameterization.items()
if self._parameters[name].is_numeric
}
for constraint in self._parameter_constraints:
if not constraint.check(numerical_param_dict):
if raise_error:
raise ValueError(f"Parameter constraint {constraint} is violated.")
return False
return True
[docs] def check_types(
self,
parameterization: TParameterization,
allow_none: bool = True,
raise_error: bool = False,
) -> bool:
"""Checks that the given parameterization's types match the search space.
Checks that the names of the parameterization match those specified in
the search space, and the given values are of the correct type.
Args:
parameterization: Dict from parameter name to value to validate.
allow_none: Whether None is a valid parameter value.
raise_error: If true and parameterization does not belong, raises an error
with detailed explanation of why.
Returns:
Whether the parameterization has valid types.
"""
if len(parameterization) != len(self._parameters):
if raise_error:
raise ValueError(
f"Parameterization has {len(parameterization)} parameters "
f"but search space has {len(self._parameters)}."
)
return False
for name, value in parameterization.items():
if name not in self._parameters:
if raise_error:
raise ValueError(f"Parameter {name} not defined in search space")
return False
if value is None and allow_none:
continue
if not self._parameters[name].is_valid_type(value):
if raise_error:
raise ValueError(
f"{value} is not a valid value for "
f"parameter {self._parameters[name]}"
)
return False
return True
[docs] def cast_arm(self, arm: Arm) -> Arm:
"""Cast parameterization of given arm to the types in this SearchSpace.
For each parameter in given arm, cast it to the proper type specified
in this search space. Throws if there is a mismatch in parameter names. This is
mostly useful for int/float, which user can be sloppy with when hand written.
Args:
arm: Arm to cast.
Returns:
New casted arm.
"""
new_parameters: TParameterization = {}
for name, value in arm.parameters.items():
# Allow raw values for out of space parameters.
if name not in self._parameters:
new_parameters[name] = value
else:
new_parameters[name] = self._parameters[name]._cast(value)
return Arm(new_parameters, arm.name if arm.has_name else None)
[docs] def out_of_design_arm(self) -> Arm:
"""Create a default out-of-design arm.
An out of design arm contains values for some parameters which are
outside of the search space. In the modeling conversion, these parameters
are all stripped down to an empty dictionary, since the point is already
outside of the modeled space.
Returns:
New arm w/ null parameter values.
"""
parameters = {}
for p_name in self.parameters.keys():
parameters[p_name] = None
return Arm(parameters)
[docs] def clone(self) -> "SearchSpace":
return SearchSpace(
parameters=[p.clone() for p in self._parameters.values()],
parameter_constraints=[pc.clone() for pc in self._parameter_constraints],
)
def _validate_parameter_constraints(
self, parameter_constraints: List[ParameterConstraint]
) -> None:
for constraint in parameter_constraints:
if isinstance(constraint, OrderConstraint) or isinstance(
constraint, SumConstraint
):
for parameter in constraint.parameters:
if parameter.name not in self._parameters.keys():
raise ValueError(
f"`{parameter.name}` does not exist in search space."
)
if parameter != self._parameters[parameter.name]:
raise ValueError(
f"Parameter constraint's definition of '{parameter.name}' "
"does not match the SearchSpace's definition"
)
else:
for parameter_name in constraint.constraint_dict.keys():
if parameter_name not in self._parameters.keys():
raise ValueError(
f"`{parameter_name}` does not exist in search space."
)
def __repr__(self) -> str:
return (
"SearchSpace("
"parameters=" + repr(list(self._parameters.values())) + ", "
"parameter_constraints=" + repr(self._parameter_constraints) + ")"
)
