Performance

docs/user-guide/dream/dream-data-reduction.ipynb

@@ -181,9 +181,10 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "intermediates[MaskedData[SampleRun]].bins.concat().hist(\n",
-    "    two_theta=300, wavelength=300\n",
-    ").plot(norm=\"log\")"
+    "two_theta = sc.linspace(\"two_theta\", 0.8, 2.4, 301, unit=\"rad\")\n",
+    "intermediates[MaskedData[SampleRun]].hist(two_theta=two_theta, wavelength=300).plot(\n",
+    "    norm=\"log\"\n",
+    ")"
    ]
   },
   {

docs/user-guide/dream/dream-instrument-view.ipynb

@@ -48,11 +48,6 @@
     "\n",
     "# Extract the events from nested data groups\n",
     "dg = sc.DataGroup({key: detector[\"events\"] for key, detector in dg.items()})\n",
-    "\n",
-    "# Construct the pixel positions from event positions\n",
-    "for da in dg.values():\n",
-    "    da.coords[\"position\"] = da.bins.coords[\"position\"].bins.mean()\n",
-    "\n",
     "dg"
    ]
   },

src/ess/dream/io/geant4.py

@@ -102,8 +102,10 @@ def _group(detectors: Dict[str, sc.DataArray]) -> Dict[str, sc.DataGroup]:
     def group(key: str, da: sc.DataArray) -> sc.DataArray:
         if key in ["high_resolution", "sans"]:
             # Only the HR and SANS detectors have sectors.
-            return da.group("sector", *elements)
-        res = da.group(*elements)
+            res = da.group("sector", *elements)
+        else:
+            res = da.group(*elements)
+        res.coords['position'] = res.bins.coords.pop('position').bins.mean()
         res.bins.coords.pop("sector", None)
         return res
 
@@ -167,15 +169,11 @@ def _extract_detector(
     return events
 
 
-def get_source_position(
-    raw_source: RawSource[RunType],
-) -> SourcePosition[RunType]:
+def get_source_position(raw_source: RawSource[RunType]) -> SourcePosition[RunType]:
     return SourcePosition[RunType](raw_source["position"])
 
 
-def get_sample_position(
-    raw_sample: RawSample[RunType],
-) -> SamplePosition[RunType]:
+def get_sample_position(raw_sample: RawSample[RunType]) -> SamplePosition[RunType]:
     return SamplePosition[RunType](raw_sample["position"])
 
 
@@ -184,10 +182,11 @@ def patch_detector_data(
     source_position: SourcePosition[RunType],
     sample_position: SamplePosition[RunType],
 ) -> ReducibleDetectorData[RunType]:
-    out = detector_data.copy(deep=False)
-    out.coords["source_position"] = source_position
-    out.coords["sample_position"] = sample_position
-    return ReducibleDetectorData[RunType](out)
+    return ReducibleDetectorData[RunType](
+        detector_data.assign_coords(
+            source_position=source_position, sample_position=sample_position
+        )
+    )
 
 
 def geant4_detector_dimensions(

src/ess/powder/conversion.py

@@ -203,11 +203,13 @@ def convert_to_dspacing(
 ) -> DspacingData[RunType]:
     if calibration is None:
         out = data.transform_coords(["dspacing"], graph=graph, keep_intermediate=False)
-        return DspacingData[RunType](out)
-    out = to_dspacing_with_calibration(data, calibration=calibration)
-    for key in ('wavelength', 'two_theta'):
-        if key in out.coords.keys():
-            out.coords.set_aligned(key, False)
+    else:
+        out = to_dspacing_with_calibration(data, calibration=calibration)
+        for key in ('wavelength', 'two_theta'):
+            if key in out.coords.keys():
+                out.coords.set_aligned(key, False)
+    out.bins.coords.pop('tof', None)
+    out.bins.coords.pop('wavelength', None)
     return DspacingData[RunType](out)
 
 

src/ess/powder/grouping.py

@@ -2,6 +2,8 @@
 # Copyright (c) 2023 Scipp contributors (https://github.com/scipp)
 """Grouping and merging of pixels / voxels."""
 
+import scipp as sc
+
 from .types import (
     DspacingBins,
     DspacingData,
@@ -12,23 +14,41 @@
 )
 
 
+def _drop_grouping_and_bin(
+    data: sc.DataArray, *, dims_to_reduce: tuple[str, ...] | None = None, edges: dict
+) -> sc.DataArray:
+    all_pixels = data if dims_to_reduce == () else data.bins.concat(dims_to_reduce)
+    # all_pixels may just have a single bin now, which currently yields
+    # inferior performance when binning (no/bad multi-threading?).
+    # We operate on the content buffer for better multi-threaded performance.
+    if all_pixels.ndim == 0:
+        return (
+            all_pixels.value.bin(**edges)
+            .assign_coords(all_pixels.coords)
+            .assign_masks(all_pixels.masks)
+        )
+    else:
+        return all_pixels.bin(**edges)
+
+
 def focus_data_dspacing(
-    data: DspacingData[RunType],
-    dspacing_bins: DspacingBins,
+    data: DspacingData[RunType], dspacing_bins: DspacingBins
 ) -> FocussedDataDspacing[RunType]:
-    out = data.bins.concat().bin({dspacing_bins.dim: dspacing_bins})
-    return FocussedDataDspacing[RunType](out)
+    return FocussedDataDspacing[RunType](
+        _drop_grouping_and_bin(data, edges={dspacing_bins.dim: dspacing_bins})
+    )
 
 
 def focus_data_dspacing_and_two_theta(
     data: DspacingData[RunType],
     dspacing_bins: DspacingBins,
     twotheta_bins: TwoThetaBins,
 ) -> FocussedDataDspacingTwoTheta[RunType]:
-    bins = {twotheta_bins.dim: twotheta_bins, dspacing_bins.dim: dspacing_bins}
-    if "two_theta" in data.bins.coords:
-        data = data.bins.concat()
-    return FocussedDataDspacingTwoTheta[RunType](data.bin(**bins))
+    return FocussedDataDspacingTwoTheta[RunType](
+        data.bin({twotheta_bins.dim: twotheta_bins}).bin(
+            {dspacing_bins.dim: dspacing_bins}
+        )
+    )
 
 
 providers = (focus_data_dspacing, focus_data_dspacing_and_two_theta)

tests/dream/geant4_reduction_test.py

@@ -136,7 +136,7 @@ def test_pipeline_two_theta_masking(providers, params):
     pipeline = sciline.Pipeline(providers, params=params)
     pipeline = powder.with_pixel_mask_filenames(pipeline, [])
     masked_sample = pipeline.compute(MaskedData[SampleRun])
-    assert 'two_theta' in masked_sample.bins.masks
+    assert 'two_theta' in masked_sample.masks
     sum_in_masked_region = (
         masked_sample.bin(two_theta=sc.concat([tmin, tmax], dim='two_theta')).sum().data
     )

tests/dream/io/geant4_test.py

@@ -113,7 +113,7 @@ def test_load_geant4_csv_mantle_has_expected_coords(file):
     assert "sector" not in mantle.bins.coords
     assert "tof" in mantle.bins.coords
     assert "wavelength" in mantle.bins.coords
-    assert "position" in mantle.bins.coords
+    assert "position" in mantle.coords
 
 
 def test_load_geant4_csv_endcap_backward_has_expected_coords(file):
@@ -128,7 +128,7 @@ def test_load_geant4_csv_endcap_backward_has_expected_coords(file):
     assert "sector" not in endcap.bins.coords
     assert "tof" in endcap.bins.coords
     assert "wavelength" in endcap.bins.coords
-    assert "position" in endcap.bins.coords
+    assert "position" in endcap.coords
 
 
 def test_load_geant4_csv_endcap_forward_has_expected_coords(file):
@@ -143,7 +143,7 @@ def test_load_geant4_csv_endcap_forward_has_expected_coords(file):
     assert "sector" not in endcap.bins.coords
     assert "tof" in endcap.bins.coords
     assert "wavelength" in endcap.bins.coords
-    assert "position" in endcap.bins.coords
+    assert "position" in endcap.coords
 
 
 def test_load_geant4_csv_high_resolution_has_expected_coords(file):
@@ -157,7 +157,7 @@ def test_load_geant4_csv_high_resolution_has_expected_coords(file):
 
     assert "tof" in hr.bins.coords
     assert "wavelength" in hr.bins.coords
-    assert "position" in hr.bins.coords
+    assert "position" in hr.coords
 
 
 def test_load_geant4_csv_sans_has_expected_coords(file):
@@ -174,7 +174,7 @@ def test_load_geant4_csv_sans_has_expected_coords(file):
 
     assert "tof" in sans.bins.coords
     assert "wavelength" in sans.bins.coords
-    assert "position" in sans.bins.coords
+    assert "position" in sans.coords
 
 
 def test_geant4_in_pipeline(file_path, file):