from __future__ import annotations
from collections.abc import Sequence
from typing import TYPE_CHECKING, ClassVar
from qcodes.instrument import Instrument, InstrumentBase, InstrumentModule
from qcodes.parameters import DelegateParameter, Parameter
if TYPE_CHECKING:
from collections.abc import Iterable
DOES_NOT_EXIST = "Does not exist"
[docs]
class InferError(AttributeError): ...
[docs]
class InferAttrs:
"""Holds a global set of attribute name that will be inferred"""
_known_attrs: ClassVar[set[str]] = set()
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@classmethod
def add(cls, attrs: str | Iterable[str]) -> None:
if isinstance(attrs, str):
attrs = (attrs,)
cls._known_attrs.update(set(attrs))
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@classmethod
def known_attrs(cls) -> tuple[str, ...]:
return tuple(cls._known_attrs)
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@classmethod
def discard(cls, attr: str) -> None:
cls._known_attrs.discard(attr)
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@classmethod
def clear(cls) -> None:
cls._known_attrs = set()
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def get_root_parameter(
param: Parameter,
alt_source_attrs: Sequence[str] | None = None,
) -> Parameter:
"""
Return the root parameter in a chain of DelegateParameters or other linking Parameters
This method calls get_parameter_chain and then checks for various error conditions
Args:
param: The DelegateParameter or other linking parameter to find the root parameter from
alt_source_attrs: The attribute names for custom linking parameters
Raises:
InferError: If the linking parameters do not end with a non-linking parameter
InferError: If the chain of linking parameters loops on itself
"""
parameter_chain = get_parameter_chain(param, alt_source_attrs)
root_param = parameter_chain[-1]
if root_param is parameter_chain[0] and len(parameter_chain) > 1:
raise InferError(f"{param} generated a loop of linking parameters")
if isinstance(root_param, DelegateParameter):
raise InferError(f"Parameter {param} is not attached to a source")
alt_source_attrs_set = _merge_user_and_class_attrs(alt_source_attrs)
for alt_source_attr in alt_source_attrs_set:
alt_source = getattr(param, alt_source_attr, DOES_NOT_EXIST)
if alt_source is None:
raise InferError(
f"Parameter {param} is not attached to a source on attribute {alt_source_attr}"
)
return root_param
[docs]
def infer_instrument(
param: Parameter,
alt_source_attrs: Sequence[str] | None = None,
) -> InstrumentBase:
"""
Find the instrument that owns a parameter or delegate parameter.
Args:
param: The DelegateParameter or other linking parameter to find the instrument from
alt_source_attrs: The attribute names for custom linking parameters
Raises:
InferError: If the linking parameters do not end with a non-linking parameter
InferError: If the instrument of the root parameter is None
InferError: If the instrument of the root parameter is not an instance of Instrument
"""
root_param = get_root_parameter(param, alt_source_attrs=alt_source_attrs)
instrument = get_instrument_from_param(root_param)
if isinstance(instrument, InstrumentModule):
return instrument.root_instrument
elif isinstance(instrument, Instrument):
return instrument
raise InferError(f"Could not determine source instrument for parameter {param}")
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def infer_instrument_module(
param: Parameter,
alt_source_attrs: Sequence[str] | None = None,
) -> InstrumentModule:
"""
Find the instrument module that owns a parameter or delegate parameter
Args:
param: The DelegateParameter or other linking parameter to find the instrument module from
alt_source_attrs: The attribute names for custom linking parameters
Raises:
InferError: If the linking parameters do not end with a non-linking parameter
InferError: If the instrument module of the root parameter is None
InferError: If the instrument module of the root parameter is not an instance of InstrumentModule
"""
root_param = get_root_parameter(param, alt_source_attrs=alt_source_attrs)
channel = get_instrument_from_param(root_param)
if isinstance(channel, InstrumentModule):
return channel
raise InferError(
f"Could not determine a root instrument channel for parameter {param}"
)
[docs]
def infer_channel(
param: Parameter,
alt_source_attrs: Sequence[str] | None = None,
) -> InstrumentModule:
"""An alias for infer_instrument_module"""
return infer_instrument_module(param, alt_source_attrs)
def get_instrument_from_param(
param: Parameter,
) -> InstrumentBase:
"""
Return the instrument attribute from a parameter
Args:
param: The parameter to get the instrument module from
Raises:
InferError: If the parameter does not have an instrument
"""
if param.instrument is not None:
return param.instrument
raise InferError(f"Parameter {param} has no instrument")
def get_parameter_chain(
param_chain: Parameter | Sequence[Parameter],
alt_source_attrs: str | Sequence[str] | None = None,
) -> tuple[Parameter, ...]:
"""
Return the chain of DelegateParameters or other linking Parameters
This method traverses singly-linked parameters and returns the resulting chain
If the parameters loop, then the first and last linking parameters in the chain
will be identical. Otherwise, the chain starts with the initial argument passed
and ends when the chain terminates in either a non-linking parameter or a
linking parameter that links to None
The search prioritizes the `source` attribute of DelegateParameters first, and
then looks for other linking attributes in undetermined order.
Args:
param_chain: The initial linking parameter or a List linking parameters
from which to return the chain
alt_source_attrs: The attribute names for custom linking parameters
"""
alt_source_attrs_set = _merge_user_and_class_attrs(alt_source_attrs)
if not isinstance(param_chain, Sequence):
param_chain = (param_chain,)
param = param_chain[-1]
mutable_param_chain = list(param_chain)
if isinstance(param, DelegateParameter):
if param.source is None:
return tuple(param_chain)
mutable_param_chain.append(param.source)
if param.source in param_chain: # There is a loop in the links
return tuple(mutable_param_chain)
return get_parameter_chain(
mutable_param_chain,
alt_source_attrs=alt_source_attrs,
)
for alt_source_attr in alt_source_attrs_set:
alt_source = getattr(param, alt_source_attr, DOES_NOT_EXIST)
if alt_source is None: # Valid linking attribute, but no link parameter
return tuple(param_chain)
elif isinstance(alt_source, Parameter):
mutable_param_chain.append(alt_source)
if alt_source in param_chain: # There is a loop in the links
return tuple(mutable_param_chain)
return get_parameter_chain(
mutable_param_chain,
alt_source_attrs=alt_source_attrs,
)
return tuple(param_chain)
def _merge_user_and_class_attrs(
alt_source_attrs: str | Sequence[str] | None = None,
) -> Iterable[str]:
"""Merges user-supplied linking attributes with attributes from InferAttrs"""
if alt_source_attrs is None:
return InferAttrs.known_attrs()
elif isinstance(alt_source_attrs, str):
return set.union(set((alt_source_attrs,)), set(InferAttrs.known_attrs()))
else:
return set.union(set(alt_source_attrs), set(InferAttrs.known_attrs()))