cara/caimira/monte_carlo/models.py
2022-09-09 16:57:20 +02:00

125 lines
4.9 KiB
Python

import copy
import dataclasses
import sys
import typing
import caimira.models
from .sampleable import SampleableDistribution, _VectorisedFloatOrSampleable
_ModelType = typing.TypeVar('_ModelType')
class MCModelBase(typing.Generic[_ModelType]):
"""
A model base class for monte carlo types.
This base class is essentially a declarative description of a caimira.models
model with a :meth:`.build_model` method to generate an appropriate
``caimira.models` model instance on demand.
"""
_base_cls: typing.Type[_ModelType]
@classmethod
def _to_vectorized_form(cls, item, size):
if isinstance(item, SampleableDistribution):
return item.generate_samples(size)
elif isinstance(item, MCModelBase):
# Recurse into other MCModelBase instances by calling their
# build_model method.
return item.build_model(size)
elif isinstance(item, tuple):
return tuple(cls._to_vectorized_form(sub, size) for sub in item)
else:
return item
def build_model(self, size: int) -> _ModelType:
"""
Turn this MCModelBase subclass into a caimira.model Model instance
from which you can then run the model.
"""
kwargs = {}
for field in dataclasses.fields(self._base_cls):
attr = getattr(self, field.name)
kwargs[field.name] = self._to_vectorized_form(attr, size)
return self._base_cls(**kwargs) # type: ignore
def _build_mc_model(model: _ModelType) -> typing.Type[MCModelBase[_ModelType]]:
"""
Generate a new MCModelBase subclass for the given caimira.models model.
"""
fields = []
for field in dataclasses.fields(model):
# Note: deepcopy not needed here as we aren't mutating entities beyond
# the top level.
new_field = copy.copy(field)
if field.type is caimira.models._VectorisedFloat: # noqa
new_field.type = _VectorisedFloatOrSampleable # type: ignore
field_type: typing.Any = new_field.type
if getattr(field_type, '__origin__', None) in [typing.Union, typing.Tuple]:
# It is challenging to generalise this code, so we provide specific transformations,
# and raise for unforseen cases.
if new_field.type == typing.Tuple[caimira.models._VentilationBase, ...]:
VB = getattr(sys.modules[__name__], "_VentilationBase")
field_type = typing.Tuple[typing.Union[caimira.models._VentilationBase, VB], ...]
elif new_field.type == typing.Tuple[caimira.models._ExpirationBase, ...]:
EB = getattr(sys.modules[__name__], "_ExpirationBase")
field_type = typing.Tuple[typing.Union[caimira.models._ExpirationBase, EB], ...]
elif new_field.type == typing.Tuple[caimira.models.SpecificInterval, ...]:
SI = getattr(sys.modules[__name__], "SpecificInterval")
field_type = typing.Tuple[typing.Union[caimira.models.SpecificInterval, SI], ...]
else:
# Check that we don't need to do anything with this type.
for item in new_field.type.__args__:
if getattr(item, '__module__', None) == 'caimira.models':
raise ValueError(
f"unsupported type annotation transformation required for {new_field.type}")
elif field_type.__module__ == 'caimira.models':
mc_model = getattr(sys.modules[__name__], new_field.type.__name__)
field_type = typing.Union[new_field.type, mc_model]
fields.append((new_field.name, field_type, new_field))
bases = []
# Update the inheritance/based to use the new MC classes, rather than the caimira.models ones.
for model_base in model.__bases__: # type: ignore
if model_base is object:
bases.append(MCModelBase)
else:
mc_model = getattr(sys.modules[__name__], model_base.__name__)
bases.append(mc_model)
cls = dataclasses.make_dataclass(
model.__name__, # type: ignore
fields, # type: ignore
bases=tuple(bases), # type: ignore
namespace={'_base_cls': model},
# This thing can be mutable - the calculations live on
# the wrapped class, not on the MCModelBase.
frozen=False,
)
# Update the module of the generated class to be this one. Without this the
# module will be "types".
cls.__module__ = __name__
return cls
_MODEL_CLASSES = [
cls for cls in vars(caimira.models).values()
if dataclasses.is_dataclass(cls)
]
# Inject the runtime generated MC types into this module.
for _model in _MODEL_CLASSES:
setattr(sys.modules[__name__], _model.__name__, _build_mc_model(_model))
# Make sure that each of the models is imported if you do a ``import *``.
__all__ = [_model.__name__ for _model in _MODEL_CLASSES] + ["MCModelBase"]