From cc95c0fade5384ab3b2628c8ba89eb0b3c91c4fd Mon Sep 17 00:00:00 2001
From: Jan-Lukas Wynen <jan-lukas.wynen@ess.eu>
Date: Mon, 4 Mar 2024 13:45:45 +0100
Subject: [PATCH 1/3] Add missing py.typed

---
 src/ess/dream/py.typed | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 create mode 100644 src/ess/dream/py.typed

diff --git a/src/ess/dream/py.typed b/src/ess/dream/py.typed
new file mode 100644
index 00000000..e69de29b

From 70338cfd8c7f1e7cdf30e1c4e08cf234d335bd68 Mon Sep 17 00:00:00 2001
From: Jan-Lukas Wynen <jan-lukas.wynen@ess.eu>
Date: Mon, 4 Mar 2024 14:12:43 +0100
Subject: [PATCH 2/3] Move ess.diffraction.* into ess.powder

---
 docs/api-reference/index.md                   |  36 ++---
 docs/examples/POWGEN_data_reduction.ipynb     |  72 +++++++++-
 src/ess/diffraction/__init__.py               |  41 ------
 src/ess/diffraction/correction.py             | 125 ------------------
 src/ess/diffraction/powder/__init__.py        |  14 --
 src/ess/powder/__init__.py                    |  25 ++++
 .../{diffraction => }/powder/conversion.py    |   8 +-
 .../{diffraction => }/powder/correction.py    | 123 ++++++++++++++++-
 .../external/__init__.py                      |   0
 .../external/powgen/__init__.py               |   0
 .../external/powgen/beamline.py               |   0
 .../external/powgen/data.py                   |   0
 .../external/powgen/instrument_view.py        |   0
 .../external/powgen/types.py                  |   0
 src/ess/{diffraction => powder}/filtering.py  |   0
 src/ess/{diffraction => powder}/grouping.py   |   1 +
 src/ess/{diffraction => powder}/logging.py    |   5 +-
 src/ess/powder/py.typed                       |   0
 src/ess/{diffraction => powder}/smoothing.py  |   2 +-
 src/ess/{diffraction => powder}/types.py      |   2 +-
 .../{diffraction => powder}/uncertainty.py    |   0
 .../conversion_test.py}                       |   2 +-
 .../correction_test.py}                       |   3 +-
 .../external/powgen/powgen_reduction_test.py  |  11 +-
 .../{diffraction => powder}/filtering_test.py |   2 +-
 tests/{diffraction => powder}/load_test.py    |   4 +-
 26 files changed, 246 insertions(+), 230 deletions(-)
 delete mode 100644 src/ess/diffraction/correction.py
 delete mode 100644 src/ess/diffraction/powder/__init__.py
 create mode 100644 src/ess/powder/__init__.py
 rename src/ess/{diffraction => }/powder/conversion.py (94%)
 rename src/ess/{diffraction => }/powder/correction.py (50%)
 rename src/ess/{diffraction => powder}/external/__init__.py (100%)
 rename src/ess/{diffraction => powder}/external/powgen/__init__.py (100%)
 rename src/ess/{diffraction => powder}/external/powgen/beamline.py (100%)
 rename src/ess/{diffraction => powder}/external/powgen/data.py (100%)
 rename src/ess/{diffraction => powder}/external/powgen/instrument_view.py (100%)
 rename src/ess/{diffraction => powder}/external/powgen/types.py (100%)
 rename src/ess/{diffraction => powder}/filtering.py (100%)
 rename src/ess/{diffraction => powder}/grouping.py (97%)
 rename src/ess/{diffraction => powder}/logging.py (64%)
 create mode 100644 src/ess/powder/py.typed
 rename src/ess/{diffraction => powder}/smoothing.py (98%)
 rename src/ess/{diffraction => powder}/types.py (98%)
 rename src/ess/{diffraction => powder}/uncertainty.py (100%)
 rename tests/{diffraction/powder/conversions_test.py => powder/conversion_test.py} (98%)
 rename tests/{diffraction/powder/corrections_test.py => powder/correction_test.py} (98%)
 rename tests/{diffraction => powder}/external/powgen/powgen_reduction_test.py (89%)
 rename tests/{diffraction => powder}/filtering_test.py (99%)
 rename tests/{diffraction => powder}/load_test.py (92%)

diff --git a/docs/api-reference/index.md b/docs/api-reference/index.md
index 250b4a98..899dd6b1 100644
--- a/docs/api-reference/index.md
+++ b/docs/api-reference/index.md
@@ -1,8 +1,10 @@
 # API Reference
 
-## Module Attributes
+## Esspowder
+
+### Module Attributes
 ```{eval-rst}
-.. currentmodule:: ess.diffraction
+.. currentmodule:: ess.powder
 
 .. autosummary::
    :toctree: ../generated/attributes
@@ -10,26 +12,7 @@
    providers
 ```
 
-## Top-level functions
-
-```{eval-rst}
-.. autosummary::
-   :toctree: ../generated/functions
-   :recursive:
-
-   crop_tof
-   filter_events
-   finalize_histogram
-   group_by_two_theta
-   lowpass
-   merge_all_pixels
-   normalize_by_monitor
-   normalize_by_proton_charge
-   normalize_by_vanadium
-   remove_bad_pulses
-```
-
-## Submodules
+### Submodules
 
 ```{eval-rst}
 .. autosummary::
@@ -37,8 +20,13 @@
    :template: module-template.rst
    :recursive:
 
-   external.powgen
-   powder
+   conversion
+   correction
+   filtering
+   grouping
+   smoothing
    types
    uncertainty
+
+   external.powgen
 ```
\ No newline at end of file
diff --git a/docs/examples/POWGEN_data_reduction.ipynb b/docs/examples/POWGEN_data_reduction.ipynb
index 92e9767f..216b7503 100644
--- a/docs/examples/POWGEN_data_reduction.ipynb
+++ b/docs/examples/POWGEN_data_reduction.ipynb
@@ -27,9 +27,9 @@
     "import sciline\n",
     "\n",
     "import ess.diffraction\n",
-    "from ess.diffraction import powder\n",
-    "from ess.diffraction.external import powgen\n",
-    "from ess.diffraction.types import *"
+    "from ess import powder\n",
+    "from ess.powder.external import powgen\n",
+    "from ess.powder.types import *"
    ]
   },
   {
@@ -82,7 +82,6 @@
    "outputs": [],
    "source": [
     "providers = [\n",
-    "    *ess.diffraction.providers,\n",
     "    *powder.providers,\n",
     "    *powgen.providers,\n",
     "]\n",
@@ -141,6 +140,69 @@
     "Now we compute the result:"
    ]
   },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "17f4aacf-aedf-4d1d-a7f8-c970eb19d68e",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "%matplotlib widget"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "087ebe52-f246-41bc-94f3-626017d0c9c7",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "d = pipeline.compute(DspacingData[VanadiumRun])"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "03a92ca3-02fe-4a0b-934c-047ba5ddecee",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "edges = sc.geomspace('dspacing', sc.scalar(0.1, unit='Å'), sc.scalar(2.2, unit='Å'), 1000)\n",
+    "h = d.bins.concat().hist(dspacing=2000)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "2617132f-1574-4ab8-be42-bc2d1601698b",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "h.plot()"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "0d3a371d-e69f-4e27-b9b0-39250866948a",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "del h.coords['gd_prtn_chrg']\n",
+    "del h.coords['sample_position']\n",
+    "del h.coords['source_position']"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "df725cc1-4a26-4323-b85f-d43fc5eae067",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "h.save_hdf5('peaked-vanadium-spectrum.h5')"
+   ]
+  },
   {
    "cell_type": "code",
    "execution_count": null,
@@ -308,7 +370,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "from ess.diffraction.grouping import group_by_two_theta, merge_all_pixels\n",
+    "from ess.powder.grouping import group_by_two_theta, merge_all_pixels\n",
     "\n",
     "grouping_providers = list(providers)\n",
     "grouping_providers.remove(merge_all_pixels)\n",
diff --git a/src/ess/diffraction/__init__.py b/src/ess/diffraction/__init__.py
index 9adad150..f101246f 100644
--- a/src/ess/diffraction/__init__.py
+++ b/src/ess/diffraction/__init__.py
@@ -7,50 +7,9 @@
 
 import importlib.metadata
 
-from . import uncertainty
-from .correction import (
-    normalize_by_monitor,
-    normalize_by_proton_charge,
-    normalize_by_vanadium,
-)
-from .correction import providers as correction_providers
-from .filtering import crop_tof, filter_events
-from .filtering import providers as filtering_providers
-from .filtering import remove_bad_pulses
-from .grouping import finalize_histogram, group_by_two_theta, merge_all_pixels
-from .grouping import providers as grouping_providers
-from .smoothing import lowpass
-
 try:
     __version__ = importlib.metadata.version(__package__ or __name__)
 except importlib.metadata.PackageNotFoundError:
     __version__ = "0.0.0"
 
 del importlib
-
-providers = (
-    *correction_providers,
-    *filtering_providers,
-    *grouping_providers,
-    *uncertainty.providers,
-)
-"""Sciline providers for setting up a diffraction pipeline.
-
-These implement basic diffraction data-reduction functionality and need to be
-extended with instrument-specific and sub-technique-specific providers.
-"""
-del correction_providers, filtering_providers, grouping_providers
-
-__all__ = [
-    'crop_tof',
-    'filter_events',
-    'finalize_histogram',
-    'group_by_two_theta',
-    'lowpass',
-    'merge_all_pixels',
-    'normalize_by_monitor',
-    'normalize_by_proton_charge',
-    'normalize_by_vanadium',
-    'remove_bad_pulses',
-    'uncertainty',
-]
diff --git a/src/ess/diffraction/correction.py b/src/ess/diffraction/correction.py
deleted file mode 100644
index 0bffc15b..00000000
--- a/src/ess/diffraction/correction.py
+++ /dev/null
@@ -1,125 +0,0 @@
-# SPDX-License-Identifier: BSD-3-Clause
-# Copyright (c) 2023 Scipp contributors (https://github.com/scipp)
-from typing import Any, Dict, Optional
-
-import scipp as sc
-from scippneutron.conversion.graph import beamline, tof
-
-from .logging import get_logger
-from .smoothing import lowpass
-from .types import (
-    AccumulatedProtonCharge,
-    DspacingBins,
-    FilteredData,
-    FocussedData,
-    NormalizedByProtonCharge,
-    NormalizedByVanadium,
-    RunType,
-    SampleRun,
-    VanadiumRun,
-)
-
-
-def normalize_by_monitor(
-    data: sc.DataArray,
-    *,
-    monitor: sc.DataArray,
-    wavelength_edges: Optional[sc.Variable] = None,
-    smooth_args: Optional[Dict[str, Any]] = None,
-) -> sc.DataArray:
-    """
-    Normalize event data by a monitor.
-
-    The input is converted to wavelength if it does not already contain wavelengths.
-
-    Parameters
-    ----------
-    data:
-        Input event data.
-    monitor:
-        A histogrammed monitor.
-    wavelength_edges:
-        If given, rebin the monitor with these edges.
-    smooth_args:
-        If given, the monitor histogram is smoothed with
-        :func:`ess.diffraction.lowpass` before dividing into `data`.
-        `smooth_args` is passed as keyword arguments to
-        :func:`ess.diffraction.lowpass`. If ``None``, the monitor is not smoothed.
-
-    Returns
-    -------
-    :
-        `data` normalized by a monitor.
-    """
-    if 'wavelength' not in monitor.coords:
-        monitor = monitor.transform_coords(
-            'wavelength',
-            graph={**beamline.beamline(scatter=False), **tof.elastic("tof")},
-            keep_inputs=False,
-            keep_intermediate=False,
-            keep_aliases=False,
-        )
-
-    if wavelength_edges is not None:
-        monitor = monitor.rebin(wavelength=wavelength_edges)
-    if smooth_args is not None:
-        get_logger().info(
-            "Smoothing monitor for normalization using "
-            "ess.diffraction.smoothing.lowpass with %s.",
-            smooth_args,
-        )
-        monitor = lowpass(monitor, dim='wavelength', **smooth_args)
-    return data.bins / sc.lookup(func=monitor, dim='wavelength')
-
-
-def normalize_by_vanadium(
-    data: FocussedData[SampleRun],
-    vanadium: FocussedData[VanadiumRun],
-    edges: DspacingBins,
-) -> NormalizedByVanadium:
-    """
-    Normalize sample data by a vanadium measurement.
-
-    Parameters
-    ----------
-    data:
-        Sample data.
-    vanadium:
-        Vanadium data.
-    edges:
-        `vanadium` is histogrammed into these bins before dividing the data by it.
-
-    Returns
-    -------
-    :
-        `data` normalized by `vanadium`.
-    """
-    norm = sc.lookup(vanadium.hist({edges.dim: edges}), dim=edges.dim)
-    # Converting to unit 'one' because the division might produce a unit
-    # with a large scale if the proton charges in data and vanadium were
-    # measured with different units.
-    return (data.bins / norm).to(unit='one', copy=False)
-
-
-def normalize_by_proton_charge(
-    data: FilteredData[RunType], proton_charge: AccumulatedProtonCharge[RunType]
-) -> NormalizedByProtonCharge[RunType]:
-    """Normalize data by an accumulated proton charge.
-
-    Parameters
-    ----------
-    data:
-        Un-normalized data array as events or a histogram.
-    proton_charge:
-        Accumulated proton charge over the entire run.
-
-    Returns
-    -------
-    :
-        ``data / proton_charge``
-    """
-    return NormalizedByProtonCharge[RunType](data / proton_charge)
-
-
-providers = (normalize_by_proton_charge, normalize_by_vanadium)
-"""Sciline providers for diffraction corrections."""
diff --git a/src/ess/diffraction/powder/__init__.py b/src/ess/diffraction/powder/__init__.py
deleted file mode 100644
index b6f82682..00000000
--- a/src/ess/diffraction/powder/__init__.py
+++ /dev/null
@@ -1,14 +0,0 @@
-# SPDX-License-Identifier: BSD-3-Clause
-# Copyright (c) 2023 Scipp contributors (https://github.com/scipp)
-"""
-Components for powder diffraction experiments.
-"""
-from .conversion import providers as conversion_providers
-from .conversion import to_dspacing_with_calibration
-from .correction import merge_calibration
-
-providers = (*conversion_providers,)
-"""Sciline providers for powder diffraction."""
-del conversion_providers
-
-__all__ = ['merge_calibration', 'to_dspacing_with_calibration']
diff --git a/src/ess/powder/__init__.py b/src/ess/powder/__init__.py
new file mode 100644
index 00000000..a6086302
--- /dev/null
+++ b/src/ess/powder/__init__.py
@@ -0,0 +1,25 @@
+# SPDX-License-Identifier: BSD-3-Clause
+# Copyright (c) 2023 Scipp contributors (https://github.com/scipp)
+# flake8: noqa: F401
+"""
+Components for powder diffraction experiments.
+"""
+import importlib.metadata
+
+from . import conversion, correction, filtering, grouping, smoothing, uncertainty
+
+try:
+    __version__ = importlib.metadata.version(__package__ or __name__)
+except importlib.metadata.PackageNotFoundError:
+    __version__ = "0.0.0"
+
+del importlib
+
+providers = (
+    *conversion.providers,
+    *correction.providers,
+    *filtering.providers,
+    *grouping.providers,
+    *uncertainty.providers,
+)
+"""Sciline providers for powder diffraction."""
diff --git a/src/ess/diffraction/powder/conversion.py b/src/ess/powder/conversion.py
similarity index 94%
rename from src/ess/diffraction/powder/conversion.py
rename to src/ess/powder/conversion.py
index abc225a5..e002664e 100644
--- a/src/ess/diffraction/powder/conversion.py
+++ b/src/ess/powder/conversion.py
@@ -9,9 +9,9 @@
 
 import scipp as sc
 
-from ..logging import get_logger
-from ..types import CalibrationData, DspacingData, NormalizedByProtonCharge, RunType
 from .correction import merge_calibration
+from .logging import get_logger
+from .types import CalibrationData, DspacingData, NormalizedByProtonCharge, RunType
 
 
 def _dspacing_from_diff_calibration_generic_impl(t, t0, a, c):
@@ -63,7 +63,7 @@ def dspacing_from_diff_calibration(
 
     See Also
     --------
-    ess.diffraction.conversions.to_dspacing_with_calibration
+    ess.powder.conversions.to_dspacing_with_calibration
     """
     if sc.all(difa == sc.scalar(0.0, unit=difa.unit)).value:
         return _dspacing_from_diff_calibration_a0_impl(tof, tzero, difc)
@@ -131,7 +131,7 @@ def to_dspacing_with_calibration(
 
     See Also
     --------
-    ess.diffraction.conversions.dspacing_from_diff_calibration
+    ess.powder.conversions.dspacing_from_diff_calibration
     """
     if calibration is not None:
         out = merge_calibration(into=data, calibration=calibration)
diff --git a/src/ess/diffraction/powder/correction.py b/src/ess/powder/correction.py
similarity index 50%
rename from src/ess/diffraction/powder/correction.py
rename to src/ess/powder/correction.py
index ad33b01d..892a585a 100644
--- a/src/ess/diffraction/powder/correction.py
+++ b/src/ess/powder/correction.py
@@ -1,8 +1,125 @@
 # SPDX-License-Identifier: BSD-3-Clause
 # Copyright (c) 2023 Scipp contributors (https://github.com/scipp)
 """Correction algorithms for powder diffraction."""
+from typing import Any, Dict, Optional
 
 import scipp as sc
+from scippneutron.conversion.graph import beamline, tof
+
+from .logging import get_logger
+from .smoothing import lowpass
+from .types import (
+    AccumulatedProtonCharge,
+    DspacingBins,
+    FilteredData,
+    FocussedData,
+    NormalizedByProtonCharge,
+    NormalizedByVanadium,
+    RunType,
+    SampleRun,
+    VanadiumRun,
+)
+
+
+def normalize_by_monitor(
+    data: sc.DataArray,
+    *,
+    monitor: sc.DataArray,
+    wavelength_edges: Optional[sc.Variable] = None,
+    smooth_args: Optional[Dict[str, Any]] = None,
+) -> sc.DataArray:
+    """
+    Normalize event data by a monitor.
+
+    The input is converted to wavelength if it does not already contain wavelengths.
+
+    Parameters
+    ----------
+    data:
+        Input event data.
+    monitor:
+        A histogrammed monitor.
+    wavelength_edges:
+        If given, rebin the monitor with these edges.
+    smooth_args:
+        If given, the monitor histogram is smoothed with
+        :func:`ess.powder.lowpass` before dividing into `data`.
+        `smooth_args` is passed as keyword arguments to
+        :func:`ess.powder.lowpass`. If ``None``, the monitor is not smoothed.
+
+    Returns
+    -------
+    :
+        `data` normalized by a monitor.
+    """
+    if 'wavelength' not in monitor.coords:
+        monitor = monitor.transform_coords(
+            'wavelength',
+            graph={**beamline.beamline(scatter=False), **tof.elastic("tof")},
+            keep_inputs=False,
+            keep_intermediate=False,
+            keep_aliases=False,
+        )
+
+    if wavelength_edges is not None:
+        monitor = monitor.rebin(wavelength=wavelength_edges)
+    if smooth_args is not None:
+        get_logger().info(
+            "Smoothing monitor for normalization using "
+            "ess.powder.smoothing.lowpass with %s.",
+            smooth_args,
+        )
+        monitor = lowpass(monitor, dim='wavelength', **smooth_args)
+    return data.bins / sc.lookup(func=monitor, dim='wavelength')
+
+
+def normalize_by_vanadium(
+    data: FocussedData[SampleRun],
+    vanadium: FocussedData[VanadiumRun],
+    edges: DspacingBins,
+) -> NormalizedByVanadium:
+    """
+    Normalize sample data by a vanadium measurement.
+
+    Parameters
+    ----------
+    data:
+        Sample data.
+    vanadium:
+        Vanadium data.
+    edges:
+        `vanadium` is histogrammed into these bins before dividing the data by it.
+
+    Returns
+    -------
+    :
+        `data` normalized by `vanadium`.
+    """
+    norm = sc.lookup(vanadium.hist({edges.dim: edges}), dim=edges.dim)
+    # Converting to unit 'one' because the division might produce a unit
+    # with a large scale if the proton charges in data and vanadium were
+    # measured with different units.
+    return (data.bins / norm).to(unit='one', copy=False)
+
+
+def normalize_by_proton_charge(
+    data: FilteredData[RunType], proton_charge: AccumulatedProtonCharge[RunType]
+) -> NormalizedByProtonCharge[RunType]:
+    """Normalize data by an accumulated proton charge.
+
+    Parameters
+    ----------
+    data:
+        Un-normalized data array as events or a histogram.
+    proton_charge:
+        Accumulated proton charge over the entire run.
+
+    Returns
+    -------
+    :
+        ``data / proton_charge``
+    """
+    return NormalizedByProtonCharge[RunType](data / proton_charge)
 
 
 def merge_calibration(*, into: sc.DataArray, calibration: sc.Dataset) -> sc.DataArray:
@@ -24,7 +141,7 @@ def merge_calibration(*, into: sc.DataArray, calibration: sc.Dataset) -> sc.Data
 
     See Also
     --------
-    ess.diffraction.load_calibration
+    ess.powder.load_calibration
     """
     dim = calibration.dim
     if not sc.identical(into.coords[dim], calibration.coords[dim]):
@@ -110,3 +227,7 @@ def _event_or_bin_coord(da: sc.DataArray, name: str) -> sc.Variable:
     except (AttributeError, KeyError):
         # Either not binned or no event coord with this name.
         return da.coords[name]
+
+
+providers = (normalize_by_proton_charge, normalize_by_vanadium)
+"""Sciline providers for powder diffraction corrections."""
diff --git a/src/ess/diffraction/external/__init__.py b/src/ess/powder/external/__init__.py
similarity index 100%
rename from src/ess/diffraction/external/__init__.py
rename to src/ess/powder/external/__init__.py
diff --git a/src/ess/diffraction/external/powgen/__init__.py b/src/ess/powder/external/powgen/__init__.py
similarity index 100%
rename from src/ess/diffraction/external/powgen/__init__.py
rename to src/ess/powder/external/powgen/__init__.py
diff --git a/src/ess/diffraction/external/powgen/beamline.py b/src/ess/powder/external/powgen/beamline.py
similarity index 100%
rename from src/ess/diffraction/external/powgen/beamline.py
rename to src/ess/powder/external/powgen/beamline.py
diff --git a/src/ess/diffraction/external/powgen/data.py b/src/ess/powder/external/powgen/data.py
similarity index 100%
rename from src/ess/diffraction/external/powgen/data.py
rename to src/ess/powder/external/powgen/data.py
diff --git a/src/ess/diffraction/external/powgen/instrument_view.py b/src/ess/powder/external/powgen/instrument_view.py
similarity index 100%
rename from src/ess/diffraction/external/powgen/instrument_view.py
rename to src/ess/powder/external/powgen/instrument_view.py
diff --git a/src/ess/diffraction/external/powgen/types.py b/src/ess/powder/external/powgen/types.py
similarity index 100%
rename from src/ess/diffraction/external/powgen/types.py
rename to src/ess/powder/external/powgen/types.py
diff --git a/src/ess/diffraction/filtering.py b/src/ess/powder/filtering.py
similarity index 100%
rename from src/ess/diffraction/filtering.py
rename to src/ess/powder/filtering.py
diff --git a/src/ess/diffraction/grouping.py b/src/ess/powder/grouping.py
similarity index 97%
rename from src/ess/diffraction/grouping.py
rename to src/ess/powder/grouping.py
index f56c4611..bf480d5a 100644
--- a/src/ess/diffraction/grouping.py
+++ b/src/ess/powder/grouping.py
@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: BSD-3-Clause
 # Copyright (c) 2023 Scipp contributors (https://github.com/scipp)
+"""Grouping and merging of pixels / voxels."""
 
 from scippneutron.conversion.graph import beamline
 
diff --git a/src/ess/diffraction/logging.py b/src/ess/powder/logging.py
similarity index 64%
rename from src/ess/diffraction/logging.py
rename to src/ess/powder/logging.py
index ab78fa66..870503db 100644
--- a/src/ess/diffraction/logging.py
+++ b/src/ess/powder/logging.py
@@ -1,15 +1,16 @@
 # SPDX-License-Identifier: BSD-3-Clause
 # Copyright (c) 2023 Scipp contributors (https://github.com/scipp)
+"""Logging tools for ess.power."""
 
 import logging
 
 
 def get_logger() -> logging.Logger:
-    """Return the logger for ess.diffraction.
+    """Return the logger for ess.powder.
 
     Returns
     -------
     :
         The requested logger.
     """
-    return logging.getLogger('scipp.ess.diffraction')
+    return logging.getLogger('scipp.ess.powder')
diff --git a/src/ess/powder/py.typed b/src/ess/powder/py.typed
new file mode 100644
index 00000000..e69de29b
diff --git a/src/ess/diffraction/smoothing.py b/src/ess/powder/smoothing.py
similarity index 98%
rename from src/ess/diffraction/smoothing.py
rename to src/ess/powder/smoothing.py
index b6e8a456..c1cd242d 100644
--- a/src/ess/diffraction/smoothing.py
+++ b/src/ess/powder/smoothing.py
@@ -70,7 +70,7 @@ def lowpass(
     Examples
     --------
 
-       >>> from ess.diffraction import lowpass
+       >>> from ess.powder.smoothing import lowpass
        >>> x = sc.linspace(dim='x', start=1.1, stop=4.0, num=1000, unit='m')
        >>> y = sc.sin(x * sc.scalar(1.0, unit='rad/m'))
        >>> y += sc.sin(x * sc.scalar(400.0, unit='rad/m'))
diff --git a/src/ess/diffraction/types.py b/src/ess/powder/types.py
similarity index 98%
rename from src/ess/diffraction/types.py
rename to src/ess/powder/types.py
index d392b6cb..9d8e692c 100644
--- a/src/ess/diffraction/types.py
+++ b/src/ess/powder/types.py
@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: BSD-3-Clause
 # Copyright (c) 2023 Scipp contributors (https://github.com/scipp)
 
-"""This module defines the domain types used in ess.diffraction.
+"""This module defines the domain types used in ess.powder.
 
 The domain types are used to define parameters and to request results from a Sciline
 pipeline.
diff --git a/src/ess/diffraction/uncertainty.py b/src/ess/powder/uncertainty.py
similarity index 100%
rename from src/ess/diffraction/uncertainty.py
rename to src/ess/powder/uncertainty.py
diff --git a/tests/diffraction/powder/conversions_test.py b/tests/powder/conversion_test.py
similarity index 98%
rename from tests/diffraction/powder/conversions_test.py
rename to tests/powder/conversion_test.py
index e5c1ab17..8da72469 100644
--- a/tests/diffraction/powder/conversions_test.py
+++ b/tests/powder/conversion_test.py
@@ -4,7 +4,7 @@
 import pytest
 import scipp as sc
 
-from ess.diffraction.powder import to_dspacing_with_calibration
+from ess.powder.conversion import to_dspacing_with_calibration
 
 
 @pytest.fixture(params=['random', 'zero'])
diff --git a/tests/diffraction/powder/corrections_test.py b/tests/powder/correction_test.py
similarity index 98%
rename from tests/diffraction/powder/corrections_test.py
rename to tests/powder/correction_test.py
index 4fd0f042..ea3f697e 100644
--- a/tests/diffraction/powder/corrections_test.py
+++ b/tests/powder/correction_test.py
@@ -5,8 +5,7 @@
 import scipp as sc
 import scipp.testing
 
-from ess.diffraction.powder import merge_calibration
-from ess.diffraction.powder.correction import apply_lorentz_correction
+from ess.powder.correction import apply_lorentz_correction, merge_calibration
 
 
 @pytest.fixture
diff --git a/tests/diffraction/external/powgen/powgen_reduction_test.py b/tests/powder/external/powgen/powgen_reduction_test.py
similarity index 89%
rename from tests/diffraction/external/powgen/powgen_reduction_test.py
rename to tests/powder/external/powgen/powgen_reduction_test.py
index b13071d1..0981f438 100644
--- a/tests/diffraction/external/powgen/powgen_reduction_test.py
+++ b/tests/powder/external/powgen/powgen_reduction_test.py
@@ -5,7 +5,7 @@
 import sciline
 import scipp as sc
 
-from ess.diffraction.types import (
+from ess.powder.types import (
     CalibrationFilename,
     DspacingBins,
     DspacingHistogram,
@@ -20,11 +20,10 @@
 
 @pytest.fixture()
 def providers():
-    from ess import diffraction
-    from ess.diffraction import powder
-    from ess.diffraction.external import powgen
+    from ess import powder
+    from ess.powder.external import powgen
 
-    return [*diffraction.providers, *powder.providers, *powgen.providers]
+    return [*powder.providers, *powgen.providers]
 
 
 @pytest.fixture()
@@ -68,7 +67,7 @@ def test_pipeline_can_compute_intermediate_results(providers, params):
 
 
 def test_pipeline_group_by_two_theta(providers, params):
-    from ess.diffraction.grouping import group_by_two_theta, merge_all_pixels
+    from ess.powder.grouping import group_by_two_theta, merge_all_pixels
 
     providers.remove(merge_all_pixels)
     providers.append(group_by_two_theta)
diff --git a/tests/diffraction/filtering_test.py b/tests/powder/filtering_test.py
similarity index 99%
rename from tests/diffraction/filtering_test.py
rename to tests/powder/filtering_test.py
index 20de49a7..3c4b9604 100644
--- a/tests/diffraction/filtering_test.py
+++ b/tests/powder/filtering_test.py
@@ -7,7 +7,7 @@
 import numpy as np
 import scipp as sc
 
-from ess.diffraction import filtering
+from ess.powder import filtering
 
 
 def make_data_with_pulse_time(rng, n_event) -> sc.DataArray:
diff --git a/tests/diffraction/load_test.py b/tests/powder/load_test.py
similarity index 92%
rename from tests/diffraction/load_test.py
rename to tests/powder/load_test.py
index 0cebd9ab..069322d6 100644
--- a/tests/diffraction/load_test.py
+++ b/tests/powder/load_test.py
@@ -2,8 +2,8 @@
 # Copyright (c) 2023 Scipp contributors (https://github.com/scipp)
 import pytest
 
-from ess.diffraction.external import load_calibration
-from ess.diffraction.external.powgen import data
+from ess.powder.external import load_calibration
+from ess.powder.external.powgen import data
 
 
 @pytest.mark.skip(

From 00b9354aab8e3ebc39382a5abdd6d71028814a2d Mon Sep 17 00:00:00 2001
From: Jan-Lukas Wynen <jan-lukas.wynen@ess.eu>
Date: Mon, 4 Mar 2024 15:36:30 +0100
Subject: [PATCH 3/3] Fix spelling

Co-authored-by: Simon Heybrock <12912489+SimonHeybrock@users.noreply.github.com>
---
 docs/api-reference/index.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/api-reference/index.md b/docs/api-reference/index.md
index 899dd6b1..8a77ed8c 100644
--- a/docs/api-reference/index.md
+++ b/docs/api-reference/index.md
@@ -1,6 +1,6 @@
 # API Reference
 
-## Esspowder
+## ESSpowder
 
 ### Module Attributes
 ```{eval-rst}