Remove rounding and make rotation function arguments keyword-only.

src/ess/nmx/mcstas_loader.py

@@ -73,7 +73,7 @@ def load_mcstas_nexus(
 
  loaded = sc.DataArray(data=weights, coords={'t': t_list, 'id': id_list})
  coords = geometry.to_coords()
- grouped = loaded.group(coords.pop('pixel_ids'))
+ grouped = loaded.group(coords.pop('pixel_id'))
  da = grouped.fold(dim='id', sizes={'panel': len(geometry.detectors), 'id': -1})
  da.coords.update(coords)
 

src/ess/nmx/mcstas_xml.py

@@ -6,7 +6,6 @@
 from types import MappingProxyType
 from typing import Iterable, Optional, Protocol, Tuple, TypeVar, Union
 
-import numpy as np
 import scipp as sc
 
 T = TypeVar('T')
@@ -122,11 +121,14 @@ def _rotation_matrix_from_location(
  """Retrieve rotation matrix from location."""
  from .rotation import axis_angle_to_quaternion, quaternion_to_matrix
 
- theta, x, y, z = find_attributes(
- location, 'rot', 'axis-x', 'axis-y', 'axis-z'
- ).values()
- q = axis_angle_to_quaternion(x, y, z, sc.scalar(-theta, unit=angle_unit))
- return quaternion_to_matrix(*q)
+ attribs = find_attributes(location, 'axis-x', 'axis-y', 'axis-z', 'rot')
+ x, y, z, w = axis_angle_to_quaternion(
+ x=attribs['axis-x'],
+ y=attribs['axis-y'],
+ z=attribs['axis-z'],
+ theta=sc.scalar(-attribs['rot'], unit=angle_unit),
+ )
+ return quaternion_to_matrix(x=x, y=y, z=z, w=w)
 
 
 @dataclass
@@ -155,12 +157,16 @@ class DetectorDesc:
 
  @classmethod
  def from_xml(
- cls, component: _XML, type_desc: _XML, simulation_settings: SimulationSettings
+ cls,
+ *,
+ component: _XML,
+ type_desc: _XML,
+ simulation_settings: SimulationSettings,
  ) -> 'DetectorDesc':
  """Create detector description from xml component and type."""
 
  def _rotate_axis(matrix: sc.Variable, axis: sc.Variable) -> sc.Variable:
- return sc.vector(np.round((matrix * axis).values, 2))
+ return matrix * axis
 
  location = select_by_tag(component, 'location')
  rotation_matrix = _rotation_matrix_from_location(
@@ -226,7 +232,11 @@ def _find_type_desc(det: _XML) -> _XML:
  )
 
  detector_components = [
- DetectorDesc.from_xml(det, _find_type_desc(det), simulation_settings)
+ DetectorDesc.from_xml(
+ component=det,
+ type_desc=_find_type_desc(det),
+ simulation_settings=simulation_settings,
+ )
  for det in filter_by_type_prefix(filter_by_tag(tree, 'component'), 'MonNDtype')
  ]
 
@@ -246,7 +256,7 @@ class SampleDesc:
 
  @classmethod
  def from_xml(
- cls, tree: _XML, simulation_settings: SimulationSettings
+ cls, *, tree: _XML, simulation_settings: SimulationSettings
  ) -> 'SampleDesc':
  """Create sample description from xml component."""
  source_xml = select_by_type_prefix(tree, 'sampleMantid-type')
@@ -288,7 +298,7 @@ class SourceDesc:
 
  @classmethod
  def from_xml(
- cls, tree: _XML, simulation_settings: SimulationSettings
+ cls, *, tree: _XML, simulation_settings: SimulationSettings
  ) -> 'SourceDesc':
  """Create source description from xml component."""
  source_xml = select_by_type_prefix(tree, 'sourceMantid-type')
@@ -318,10 +328,10 @@ def _pixel_positions(
  Position of each pixel is relative to the position_offset.
  """
  pixel_idx = sc.arange('id', detector.total_pixels)
- n_row = sc.scalar(detector.num_fast_pixels_per_row)
+ n_col = sc.scalar(detector.num_fast_pixels_per_row)
 
- pixel_n_slow = pixel_idx // n_row
- pixel_n_fast = pixel_idx % n_row
+ pixel_n_slow = pixel_idx // n_col
+ pixel_n_fast = pixel_idx % n_col
 
  fast_axis_steps = detector.fast_axis * detector.fast_step
  slow_axis_steps = detector.slow_axis * detector.slow_step
@@ -360,8 +370,12 @@ def from_xml(cls, tree: _XML) -> 'McStasInstrument':
  return cls(
  simulation_settings=simulation_settings,
  detectors=_collect_detector_descriptions(tree),
- source=SourceDesc.from_xml(tree, simulation_settings),
- sample=SampleDesc.from_xml(tree, simulation_settings),
+ source=SourceDesc.from_xml(
+ tree=tree, simulation_settings=simulation_settings
+ ),
+ sample=SampleDesc.from_xml(
+ tree=tree, simulation_settings=simulation_settings
+ ),
  )
 
  def to_coords(self) -> dict[str, sc.Variable]:

src/ess/nmx/rotation.py

@@ -7,7 +7,7 @@
 
 
 def axis_angle_to_quaternion(
- x: float, y: float, z: float, theta: sc.Variable
+ *, x: float, y: float, z: float, theta: sc.Variable
 ) -> NDArray:
  """Convert axis-angle to queternions, [x, y, z, w].
 
@@ -40,7 +40,7 @@ def axis_angle_to_quaternion(
  return q / np.linalg.norm(q)
 
 
-def quaternion_to_matrix(x: float, y: float, z: float, w: float) -> sc.Variable:
+def quaternion_to_matrix(*, x: float, y: float, z: float, w: float) -> sc.Variable:
  """Convert quaternion to rotation matrix.
 
  Parameters

tests/loader_test.py

@@ -10,6 +10,7 @@
 
 
 def test_file_reader_mcstas() -> None:
+ import numpy as np
  import scippnexus as snx
 
  from ess.nmx.mcstas_loader import (
@@ -37,12 +38,13 @@ def test_file_reader_mcstas() -> None:
  assert sc.identical(da.data.max(), expected_weight_max)
  # Expected coordinate values are provided by the IDS
  # based on the simulation settings of the sample file.
- assert sc.identical(
- da.coords['fast_axis'],
- sc.vectors(
+ # The expected values are rounded to 2 decimal places.
+ assert np.all(
+ np.round(da.coords['fast_axis'].values, 2)
+ == sc.vectors(
  dims=['panel'],
  values=[(1.0, 0.0, -0.01), (-0.01, 0.0, -1.0), (0.01, 0.0, 1.0)],
- ),
+ ).values,
  )
  assert sc.identical(
  da.coords['slow_axis'],