Load histogram monitors

src/ess/reduce/nexus/__init__.py

@@ -13,6 +13,7 @@
 from . import types
 from ._nexus_loader import (
     load_event_data,
+    load_hist_data,
     group_event_data,
     load_component,
     compute_component_position,
@@ -23,6 +24,7 @@
     'types',
     'group_event_data',
     'load_event_data',
+    'load_hist_data',
     'load_component',
     'compute_component_position',
     'extract_events_or_histogram',

src/ess/reduce/nexus/_nexus_loader.py

@@ -147,6 +147,49 @@ def _select_unique_array(
     return next(iter(arrays.values()))
 
 
+def load_hist_data(
+    file_path: AnyRunFilename,
+    selection=(),
+    *,
+    entry_name: NeXusEntryName | None = None,
+    component_name: str,
+    definitions: Mapping | NoNewDefinitionsType = NoNewDefinitions,
+) -> sc.DataArray:
+    """Load NXdata of a detector or monitor from a NeXus file.
+
+    Parameters
+    ----------
+    file_path:
+        Indicates where to load data from.
+        One of:
+
+        - Path to a NeXus file on disk.
+        - File handle or buffer for reading binary data.
+        - A ScippNexus group of the root of a NeXus file.
+    component_name:
+        Name of the NXdetector or NXmonitor containing the NXevent_data to load.
+        Must be a group in an instrument group in the entry (see below).
+    entry_name:
+        Name of the entry that contains the detector.
+        If ``None``, the entry will be located based
+        on its NeXus class, but there cannot be more than 1.
+    definitions:
+        Definitions used by scippnexus loader, see :py:`scippnexus.File`
+        for documentation.
+
+    Returns
+    -------
+    :
+        Data array with events grouped by event_time_zero, as in the NeXus file.
+    """
+    with _open_nexus_file(file_path, definitions=definitions) as f:
+        entry = _unique_child_group(f, snx.NXentry, entry_name)
+        instrument = _unique_child_group(entry, snx.NXinstrument, None)
+        component = instrument[component_name]
+        event_data = _unique_child_group(component, snx.NXdata, None)
+        return event_data[selection]
+
+
 def load_event_data(
     file_path: AnyRunFilename,
     selection=(),

src/ess/reduce/nexus/generic_types.py

@@ -115,6 +115,12 @@ class NeXusMonitorEventData(
     """Data array loaded from a NeXus NXevent_data group within an NXmonitor."""
 
 
+class NeXusMonitorHistData(
+    sciline.ScopeTwoParams[RunType, MonitorType, sc.DataArray], sc.DataArray
+):
+    """Data array loaded from a NeXus NXdata group within an NXmonitor."""
+
+
 class SourcePosition(sciline.Scope[RunType, sc.Variable], sc.Variable):
     """Position of the neutron source."""
 
@@ -198,3 +204,10 @@ class NeXusMonitorEventLocationSpec(
     NeXusLocationSpec[snx.NXevent_data], Generic[RunType, MonitorType]
 ):
     """NeXus filename and parameters to identify (parts of) monitor events to load."""
+
+
+@dataclass
+class NeXusMonitorHistLocationSpec(
+    NeXusLocationSpec[snx.NXdata], Generic[RunType, MonitorType]
+):
+    """NeXus filename and parameters to identify a monitor histogram to load."""

src/ess/reduce/nexus/generic_workflow.py

@@ -11,6 +11,9 @@
 instrument-specific wrappers or implementations.
 """
 
+from collections.abc import Callable
+from typing import Any
+
 import sciline
 import scippnexus as snx
 
@@ -73,6 +76,16 @@ def monitor_events_by_name(
     )
 
 
+def monitor_histogram_by_name(
+    filename: gt.NeXusFileSpec[RunType],
+    name: gt.NeXusMonitorName[MonitorType],
+) -> gt.NeXusMonitorHistLocationSpec[RunType, MonitorType]:
+    return gt.NeXusMonitorHistLocationSpec[RunType, MonitorType](
+        filename=filename.value,
+        component_name=name,
+    )
+
+
 def detector_by_name(
     filename: gt.NeXusFileSpec[RunType], name: NeXusDetectorName
 ) -> gt.NeXusComponentLocationSpec[snx.NXdetector, RunType]:
@@ -133,6 +146,14 @@ def load_nexus_monitor_event_data(
     )
 
 
+def load_nexus_monitor_histogram_data(
+    location: gt.NeXusMonitorHistLocationSpec[RunType, MonitorType],
+) -> gt.NeXusMonitorHistData[RunType, MonitorType]:
+    return gt.NeXusMonitorHistData[RunType, MonitorType](
+        workflow.load_nexus_monitor_histogram_data(location)
+    )
+
+
 def get_source_position(source: gt.NeXusSource[RunType]) -> gt.SourcePosition[RunType]:
     return gt.SourcePosition[RunType](workflow.get_source_position(source))
 
@@ -181,12 +202,21 @@ def get_calibrated_monitor(
     )
 
 
-def assemble_monitor_data(
+def assemble_monitor_event_data(
     monitor: gt.CalibratedMonitor[RunType, MonitorType],
     event_data: gt.NeXusMonitorEventData[RunType, MonitorType],
 ) -> gt.MonitorData[RunType, MonitorType]:
     return gt.MonitorData[RunType, MonitorType](
-        workflow.assemble_monitor_data(monitor, event_data)
+        workflow.assemble_monitor_event_data(monitor, event_data)
+    )
+
+
+def assemble_monitor_histogram_data(
+    monitor: gt.CalibratedMonitor[RunType, MonitorType],
+    hist_data: gt.NeXusMonitorHistData[RunType, MonitorType],
+) -> gt.MonitorData[RunType, MonitorType]:
+    return gt.MonitorData[RunType, MonitorType](
+        workflow.assemble_monitor_histogram_data(monitor, hist_data)
     )
 
 
@@ -199,28 +229,50 @@ def assemble_monitor_data(
 load_nexus_monitor.__doc__ = workflow.load_nexus_monitor.__doc__
 load_nexus_detector_event_data.__doc__ = workflow.load_nexus_detector_event_data.__doc__
 load_nexus_monitor_event_data.__doc__ = workflow.load_nexus_monitor_event_data.__doc__
+load_nexus_monitor_histogram_data.__doc__ = (
+    workflow.load_nexus_monitor_histogram_data.__doc__
+)
 get_source_position.__doc__ = workflow.get_source_position.__doc__
 get_sample_position.__doc__ = workflow.get_sample_position.__doc__
 get_calibrated_detector.__doc__ = workflow.get_calibrated_detector.__doc__
 assemble_detector_data.__doc__ = workflow.assemble_detector_data.__doc__
 get_calibrated_monitor.__doc__ = workflow.get_calibrated_monitor.__doc__
-assemble_monitor_data.__doc__ = workflow.assemble_monitor_data.__doc__
+assemble_monitor_event_data.__doc__ = workflow.assemble_monitor_event_data.__doc__
+assemble_monitor_histogram_data.__doc__ = (
+    workflow.assemble_monitor_histogram_data.__doc__
+)
+monitor_events_by_name.__doc__ = workflow.monitor_events_by_name.__doc__
+monitor_histogram_by_name.__doc__ = workflow.monitor_histogram_by_name.__doc__
 
 
 _common_providers = (workflow.gravity_vector_neg_y, file_path_to_file_spec, all_pulses)
 
-_monitor_providers = (
-    no_monitor_position_offset,
-    unique_source_spec,
-    monitor_by_name,
-    monitor_events_by_name,
-    load_nexus_monitor,
-    load_nexus_monitor_event_data,
-    load_nexus_source,
-    get_source_position,
-    get_calibrated_monitor,
-    assemble_monitor_data,
-)
+
+def _monitor_providers(*, event_monitor: bool) -> tuple[Callable[..., Any], ...]:
+    if event_monitor:
+        data_providers = (
+            assemble_monitor_event_data,
+            load_nexus_monitor_event_data,
+            monitor_events_by_name,
+        )
+    else:
+        data_providers = (
+            assemble_monitor_histogram_data,
+            load_nexus_monitor_histogram_data,
+            monitor_histogram_by_name,
+        )
+
+    return (
+        no_monitor_position_offset,
+        unique_source_spec,
+        monitor_by_name,
+        load_nexus_monitor,
+        load_nexus_source,
+        get_source_position,
+        get_calibrated_monitor,
+        *data_providers,
+    )
+
 
 _detector_providers = (
     no_detector_position_offset,
@@ -239,9 +291,11 @@ def assemble_monitor_data(
 )
 
 
-def LoadMonitorWorkflow() -> sciline.Pipeline:
+def LoadMonitorWorkflow(*, event_monitor: bool = True) -> sciline.Pipeline:
     """Generic workflow for loading monitor data from a NeXus file."""
-    wf = sciline.Pipeline((*_common_providers, *_monitor_providers))
+    wf = sciline.Pipeline(
+        (*_common_providers, *_monitor_providers(event_monitor=event_monitor))
+    )
     return wf
 
 
@@ -252,10 +306,14 @@ def LoadDetectorWorkflow() -> sciline.Pipeline:
     return wf
 
 
-def GenericNeXusWorkflow() -> sciline.Pipeline:
+def GenericNeXusWorkflow(*, event_monitor: bool = True) -> sciline.Pipeline:
     """Generic workflow for loading detector and monitor data from a NeXus file."""
     wf = sciline.Pipeline(
-        (*_common_providers, *_monitor_providers, *_detector_providers)
+        (
+            *_common_providers,
+            *_monitor_providers(event_monitor=event_monitor),
+            *_detector_providers,
+        )
     )
     wf[DetectorBankSizes] = DetectorBankSizes({})
     return wf

src/ess/reduce/nexus/types.py

@@ -47,6 +47,8 @@
 """Data array loaded from a NeXus NXevent_data group within an NXdetector."""
 AnyRunAnyNeXusMonitorEventData = NewType('AnyRunAnyNeXusMonitorEventData', sc.DataArray)
 """Data array loaded from a NeXus NXevent_data group within an NXmonitor."""
+AnyRunAnyNeXusMonitorHistData = NewType('AnyRunAnyNeXusMonitorHistData', sc.DataArray)
+"""Data array loaded from a NeXus NXdata group within an NXmonitor."""
 
 AnyRunSourcePosition = NewType('AnyRunSourcePosition', sc.Variable)
 """Position of the neutron source."""
@@ -94,3 +96,8 @@ class NeXusLocationSpec(Generic[Component]):
 @dataclass
 class NeXusEventDataLocationSpec(NeXusLocationSpec[Component]):
     """NeXus filename and parameters to identify (parts of) events to load."""
+
+
+@dataclass
+class NeXusHistDataLocationSpec(NeXusLocationSpec[Component]):
+    """NeXus filename and parameters to identify (parts of) a histogram to load."""