Cannot construct cycler from Static.duration #154
Description
When constructing a cycler with a Spec that contains as one of its axes DURATION, the special string is not handled as duration. This is for a software scan.
@attach_data_session_metadata_decorator()
@validate_call(config={"arbitrary_types_allowed": True})
def spec_scan(
detectors: Annotated[
set[Readable],
Field(
description="Set of readable devices, will take a reading at each point, \
in addition to any Movables in the Spec",
),
],
spec: Annotated[
Spec[Movable],
Field(description="ScanSpec modelling the path of the scan"),
],
metadata: dict[str, Any] | None = None,
) -> MsgGenerator:
"""Generic plan for reading `detectors` at every point of a ScanSpec `Spec`.
A `Spec` is an N-dimensional path.
"""
# TODO: https://github.com/bluesky/scanspec/issues/154
# support Static.duration: Spec[Literal["DURATION"]]
_md = {
"plan_args": {
"detectors": {det.name for det in detectors},
"spec": repr(spec),
},
"plan_name": "spec_scan",
"shape": spec.shape(),
**(metadata or {}),
}
yield from bp.scan_nd(tuple(detectors), _as_cycler(spec), md=_md)
def _as_cycler(spec: Spec[Movable]) -> Cycler:
"""
Convert a scanspec to a cycler for compatibility with legacy Bluesky plans such as
`bp.scan_nd`. Use the midpoints of the scanspec since cyclers are normally used
for software triggered scans.
Args:
spec: A scanspec
Returns:
Cycler: A new cycler
"""
midpoints = spec.frames().midpoints
# Need to "add" the cyclers for all the axes together. The code below is
# effectively: cycler(motor1, [...]) + cycler(motor2, [...]) + ...
return reduce(operator.add, (cycler(*args) for args in midpoints.items()))