Enabling of parallelization of analysis.hydrogenbonds.WaterBridgeAnalysis

package/MDAnalysis/analysis/hydrogenbonds/wbridge_analysis.py

@@ -716,7 +716,7 @@ def analysis(current, output, u, **kwargs):
 from MDAnalysis.lib.distances import calc_angles, capped_distance
 from MDAnalysis.lib.NeighborSearch import AtomNeighborSearch
 
-from ..base import AnalysisBase
+from ..base import AnalysisBase, ResultsGroup
 
 logger = logging.getLogger("MDAnalysis.analysis.WaterBridgeAnalysis")
 
@@ -804,6 +804,16 @@ class WaterBridgeAnalysis(AnalysisBase):
         lambda: 1.5, N=1.31, O=1.31, P=1.58, S=1.55  # default value
     )  # noqa: E741
 
+    _analysis_algorithm_is_parallelizable = True
+
+    @classmethod
+    def get_supported_backends(cls):
+        return (
+            "serial",
+            "multiprocessing",
+            "dask",
+        )
+
     def __init__(
         self,
         universe,
@@ -1951,25 +1961,32 @@ def count_by_time(self, analysis_func=None, **kwargs):
         """
         if analysis_func is None:
             analysis_func = self._count_by_time_analysis
-        if self.results.network:
-            result = []
-            for time, frame in zip(self.timesteps, self.results.network):
-                result_dict = defaultdict(int)
-                self._traverse_water_network(
-                    frame,
-                    [],
-                    analysis_func=analysis_func,
-                    output=result_dict,
-                    link_func=self._full_link,
-                    **kwargs,
-                )
-                result.append(
-                    (time, sum([result_dict[key] for key in result_dict]))
-                )
-            return result
-        else:
+
+        if not self.results.network:
             return None
 
+        # --- simple fallback for missing timesteps ---
+        if self.timesteps is None:
+            timesteps = range(len(self.results.network))
+        else:
+            timesteps = self.timesteps
+
+        result = []
+        for time, frame in zip(timesteps, self.results.network):
+            result_dict = defaultdict(int)
+            self._traverse_water_network(
+                frame,
+                [],
+                analysis_func=analysis_func,
+                output=result_dict,
+                link_func=self._full_link,
+                **kwargs,
+            )
+            result.append(
+                (time, sum([result_dict[key] for key in result_dict]))
+            )
+        return result
+
     def _timesteps_by_type_analysis(self, current, output, *args, **kwargs):
         s1_index, to_index, s1, to_residue, dist, angle = (
             self._expand_timeseries(current[0])
@@ -2152,6 +2169,14 @@ def generate_table(self, output_format=None):
     def _conclude(self):
         self.results.timeseries = self._generate_timeseries()
 
+    def _get_aggregator(self):
+        return ResultsGroup(
+            lookup={
+                "timeseries": ResultsGroup.ndarray_hstack,  # Get positions
+                "network": ResultsGroup.ndarray_hstack,  # Get positions
+            }
+        )
+
     @property
     def network(self):
         wmsg = (

testsuite/MDAnalysisTests/analysis/conftest.py

@@ -15,6 +15,9 @@
 from MDAnalysis.analysis.hydrogenbonds.hbond_analysis import (
     HydrogenBondAnalysis,
 )
+from MDAnalysis.analysis.hydrogenbonds.wbridge_analysis import (
+    WaterBridgeAnalysis,
+)
 from MDAnalysis.analysis.nucleicacids import NucPairDist
 from MDAnalysis.analysis.contacts import Contacts
 from MDAnalysis.analysis.density import DensityAnalysis
@@ -217,3 +220,11 @@ def client_InterRDF_s(request):
 @pytest.fixture(scope="module", params=params_for_cls(DistanceMatrix))
 def client_DistanceMatrix(request):
     return request.param
+
+
+# MDAnalysis.analysis.hydrogenbonds.wbridge_analysis
+
+
+@pytest.fixture(scope="module", params=params_for_cls(WaterBridgeAnalysis))
+def client_WaterBridgeAnalysis(request):
+    return request.param