- Add tests for plane-wave cutoffs

- Correct formula `cutoff_radius`
- Correct failure handling of `cutoff_fractional`

src/nomad_simulations/schema_packages/basis_set.py

@@ -84,8 +84,11 @@ def cutoff_radius(self) -> pint.Quantity:
         """
         Compute the cutoff radius for the plane-wave basis set, expressed in reciprocal coordinates.
         """
+        if self.cutoff_energy is None:
+            return None
         m_e = const.m_e * ureg(const.unit('electron mass'))
-        return np.sqrt(2 * m_e * self.cutoff_energy)
+        h = const.h * ureg(const.unit('Planck constant'))
+        return np.sqrt(2 * m_e * self.cutoff_energy) / h
 
     def normalize(self, archive: EntryArchive, logger: BoundLogger) -> None:
         super(BasisSet, self).normalize(archive, logger)
@@ -113,16 +116,14 @@ def set_cutoff_fractional(self, mt_r_min: pint.Quantity, logger: BoundLogger) ->
         Compute the fractional cutoff parameter for the interstitial plane waves in the LAPW family.
         This parameter is defined wrt the smallest muffin-tin region.
         """
-        try:
-            self.cutoff_fractional = self.cutoff_radius / mt_r_min  # unitless
-        except AttributeError:
-            logger.warning('`MuffinTin.cutoff_energy` must be defined.')
-        except ZeroDivisionError:
-            logger.warning('`MuffinTin.radius` cannot be zero.')
-        except TypeError:
-            logger.warning(
-                '`MuffinTin.radius` and `MuffinTin.cutoff_energy` must be defined.'
-            )
+        reference_unit = 'angstrom'
+        if self.cutoff_fractional is not None:
+            logger.info('`APWPlaneWaveBasisSet.cutoff_fractional` already defined. Will not overwrite.') #! extend implementation
+            return
+        elif self.cutoff_energy is None or mt_r_min is None:
+            logger.warning('`APWPlaneWaveBasisSet.cutoff_energy` and `APWPlaneWaveBasisSet.radius` must both be defined. Aborting normalization step.')
+            return
+        self.cutoff_fractional = self.cutoff_radius.to(f'1 / {reference_unit}') * mt_r_min.to(reference_unit)
 
 
 class AtomCenteredFunction(ArchiveSection):

tests/test_basis_set.py

@@ -0,0 +1,33 @@
+from nomad.units import ureg
+import numpy as np
+from . import logger
+
+from nomad_simulations.schema_packages.basis_set import APWPlaneWaveBasisSet
+
+
+def test_cutoff():
+    """Test the quantitative results when computing certain plane-wave cutoffs."""
+    p_unit = '1 / angstrom'
+    ref_cutoff_radius = 1.823 * ureg(p_unit)
+    pw = APWPlaneWaveBasisSet(cutoff_energy=500 * ureg('eV'))
+    assert np.isclose(pw.cutoff_radius.to(p_unit).magnitude, ref_cutoff_radius.magnitude, atol=1e-3)  # reference computed by ChatGPT 4o
+
+    pw.set_cutoff_fractional(1 / ref_cutoff_radius, logger)
+    assert np.isclose(pw.cutoff_fractional, 1, rtol=1e-2)
+
+def test_cutoff_failure():
+    """Test modes where `cutoff_fractional` is not computed."""
+    # missing cutoff_energy
+    pw = APWPlaneWaveBasisSet()
+    pw.set_cutoff_fractional(ureg.angstrom, logger)
+    assert pw.cutoff_fractional is None
+
+    # missing mt_radius
+    pw = APWPlaneWaveBasisSet(cutoff_energy=500 * ureg('eV'))
+    pw.set_cutoff_fractional(None, logger)
+    assert pw.cutoff_fractional is None
+
+    # cutoff_fractional already set
+    pw = APWPlaneWaveBasisSet(cutoff_energy=500 * ureg('eV'), cutoff_fractional=1)
+    pw.set_cutoff_fractional(ureg.angstrom, logger)
+    assert pw.cutoff_fractional == 1