Convert "Quantity" to raw value for kinetic_energy and potential_ener…

…gy in OpenMM reader (#4548)

* Convert "Quantity" to raw value for kinetic_energy and potential_energy in OpenMMSimulationReader.

package/CHANGELOG

@@ -16,11 +16,12 @@ The rules for this file:
 -------------------------------------------------------------------------------
 ??/??/?? IAlibay, HeetVekariya, marinegor, lilyminium, RMeli,
          ljwoods2, aditya292002, pstaerk, PicoCentauri, BFedder,
-         tyler.je.reddy, SampurnaM, leonwehrhan, kainszs
+         tyler.je.reddy, SampurnaM, leonwehrhan, kainszs, orionarcher
 
  * 2.8.0
 
 Fixes
+ * Convert openmm Quantity to raw value for KE and PE in OpenMMSimulationReader.
  * Atomname methods can handle empty groups (Issue #2879, PR #4529)
  * Add support for TPR files produced by Gromacs 2024.1 (PR #4523)
  * Remove mutable data from ``progressbar_kwargs`` argument in ``AnalysisBase.run()``

package/MDAnalysis/converters/OpenMM.py

@@ -125,10 +125,10 @@ def _mda_timestep_from_omm_context(self):
         ts.frame = 0
         ts.data["time"] = state.getTime()._value
         ts.data["potential_energy"] = (
-            state.getPotentialEnergy().in_units_of(u.kilojoule/u.mole)
+            state.getPotentialEnergy().in_units_of(u.kilojoule/u.mole)._value
         )
         ts.data["kinetic_energy"] = (
-            state.getKineticEnergy().in_units_of(u.kilojoule/u.mole)
+            state.getKineticEnergy().in_units_of(u.kilojoule/u.mole)._value
         )
         ts.triclinic_dimensions = state.getPeriodicBoxVectors(
                 asNumpy=True)._value

testsuite/MDAnalysisTests/converters/test_openmm.py

@@ -87,6 +87,11 @@ def test_basic_topology(self, omm_sim_uni):
         assert omm_sim_uni.segments.segids[0] == '0'
         assert len(omm_sim_uni.bonds.indices) == 0
 
+    def test_data(self, omm_sim_uni):
+        data = omm_sim_uni.trajectory.ts.data
+        assert isinstance(data["kinetic_energy"], float)
+        assert isinstance(data["potential_energy"], float)
+
 
 class TestOpenMMPDBFileReader(_SingleFrameReader):
     __test__ = True