Add warning for future change of argument name for timeseries from asel -> atomgroup

package/CHANGELOG

@@ -59,6 +59,8 @@ Changes
     `analysis.nucleicacids.WatsonCrickDist.results.distances` (Issue #3720, PR #3735)
 
 Deprecations
+  * The `asel` argument to timeseries will be renamed to `atomgroup` in 3.0.0.
+    (Issue #3911)
   * MDAnalysis.lib.util is deprecated and will be removed in version 3.0
     (Issue #3649)
   * The TRZ reader & writer are deprecated and will be removed in version 3.0

package/MDAnalysis/coordinates/DCD.py

@@ -278,6 +278,7 @@ def dt(self):
 
     def timeseries(self,
                    asel=None,
+                   atomgroup=None,
                    start=None,
                    stop=None,
                    step=None,
@@ -290,6 +291,12 @@ def timeseries(self,
             The :class:`~MDAnalysis.core.groups.AtomGroup` to read the
             coordinates from. Defaults to None, in which case the full set of
             coordinate data is returned.
+
+            .. deprecated:: 2.7.0
+               asel argument will be renamed to atomgroup in 3.0.0
+
+        atomgroup: AtomGroup (optional)
+            Same as `asel`, will replace `asel` in 3.0.0
         start : int (optional)
             Begin reading the trajectory at frame index `start` (where 0 is the
             index of the first frame in the trajectory); the default ``None``
@@ -315,14 +322,22 @@ def timeseries(self,
             ValueError now raised instead of NoDataError for empty input
             AtomGroup
         """
+        if asel is not None:
+            warnings.warn(
+                "asel argument to timeseries will be renamed to"
+                "'atomgroup' in 3.0, see #3911",
+                category=DeprecationWarning)
+            if atomgroup:
+                raise ValueError("Cannot provide both asel and atomgroup kwargs")
+            atomgroup = asel
 
         start, stop, step = self.check_slice_indices(start, stop, step)
 
-        if asel is not None:
-            if len(asel) == 0:
+        if atomgroup is not None:
+            if len(atomgroup) == 0:
                 raise ValueError(
                     "Timeseries requires at least one atom to analyze")
-            atom_numbers = list(asel.indices)
+            atom_numbers = list(atomgroup.indices)
         else:
             atom_numbers = list(range(self.n_atoms))
 

package/MDAnalysis/coordinates/base.py

@@ -987,6 +987,7 @@ def __repr__(self):
         ))
 
     def timeseries(self, asel: Optional['AtomGroup']=None,
+                   atomgroup: Optional['Atomgroup']=None,
                    start: Optional[int]=None, stop: Optional[int]=None,
                    step: Optional[int]=None,
                    order: Optional[str]='fac') -> np.ndarray:
@@ -998,6 +999,12 @@ def timeseries(self, asel: Optional['AtomGroup']=None,
             The :class:`~MDAnalysis.core.groups.AtomGroup` to read the
             coordinates from. Defaults to ``None``, in which case the full set
             of coordinate data is returned.
+
+            .. deprecated:: 2.7.0
+            asel argument will be renamed to atomgroup in 3.0.0
+
+        atomgroup: AtomGroup (optional)
+            Same as `asel`, will replace `asel` in 3.0.0
         start :  int (optional)
             Begin reading the trajectory at frame index `start` (where 0 is the
             index of the first frame in the trajectory); the default
@@ -1023,14 +1030,22 @@ def timeseries(self, asel: Optional['AtomGroup']=None,
 
         .. versionadded:: 2.4.0
         """
+        if asel is not None:
+            warnings.warn(
+                "asel argument to timeseries will be renamed to"
+                "'atomgroup' in 3.0, see #3911",
+                category=DeprecationWarning)
+            if atomgroup:
+                raise ValueError("Cannot provide both asel and atomgroup kwargs")
+            atomgroup = asel
         start, stop, step = self.check_slice_indices(start, stop, step)
         nframes = len(range(start, stop, step))
 
-        if asel is not None:
-            if len(asel) == 0:
+        if atomgroup is not None:
+            if len(atomgroup) == 0:
                 raise ValueError(
                     "Timeseries requires at least one atom to analyze")
-            atom_numbers = asel.indices
+            atom_numbers = atomgroup.indices
             natoms = len(atom_numbers)
         else:
             natoms = self.n_atoms

package/MDAnalysis/coordinates/memory.py

@@ -488,7 +488,7 @@ def _reopen(self):
         self.ts.frame = -1
         self.ts.time = -1
 
-    def timeseries(self, asel=None, start=0, stop=-1, step=1, order='afc'):
+    def timeseries(self, asel=None, atomgroup=None, start=0, stop=-1, step=1, order='afc'):
         """Return a subset of coordinate data for an AtomGroup in desired
         column order. If no selection is given, it will return a view of the
         underlying array, while a copy is returned otherwise.
@@ -500,6 +500,12 @@ def timeseries(self, asel=None, start=0, stop=-1, step=1, order='afc'):
             coordinate data is returned. Note that in this case, a view
             of the underlying numpy array is returned, while a copy of the
             data is returned whenever `asel` is different from ``None``.
+
+            .. deprecated:: 2.7.0
+               asel argument will be renamed to atomgroup in 3.0.0
+
+        atomgroup: AtomGroup (optional)
+            Same as `asel`, will replace `asel` in 3.0.0
         start : int (optional)
             the start trajectory frame
         stop : int (optional)
@@ -525,6 +531,16 @@ def timeseries(self, asel=None, start=0, stop=-1, step=1, order='afc'):
             ValueError now raised instead of NoDataError for empty input
             AtomGroup
         """
+        if asel is not None:
+            warnings.warn(
+                "asel argument to timeseries will be renamed to"
+                "'atomgroup' in 3.0, see #3911",
+                category=DeprecationWarning)
+            if atomgroup:
+                raise ValueError("Cannot provide both asel and atomgroup kwargs")
+            atomgroup = asel
+
+
         if stop != -1:
             warnings.warn("MemoryReader.timeseries inclusive `stop` "
                       "indexing will be removed in 3.0 in favour of exclusive "
@@ -556,13 +572,13 @@ def timeseries(self, asel=None, start=0, stop=-1, step=1, order='afc'):
                        [slice(None)] * (2-f_index))
 
         # Return a view if either:
-        #   1) asel is None
-        #   2) asel corresponds to the selection of all atoms.
+        #   1) atomgroup is None
+        #   2) atomgroup corresponds to the selection of all atoms.
         array = array[tuple(basic_slice)]
-        if (asel is None or asel is asel.universe.atoms):
+        if (atomgroup is None or atomgroup is atomgroup.universe.atoms):
             return array
         else:
-            if len(asel) == 0:
+            if len(atomgroup) == 0:
                 raise ValueError("Timeseries requires at least one atom "
                                   "to analyze")
             # If selection is specified, return a copy

testsuite/MDAnalysisTests/coordinates/base.py

@@ -499,7 +499,29 @@ def test_timeseries_empty_asel(self, reader):
                           match="Empty string to select atoms, empty group returned."):
             atoms = mda.Universe(reader.filename).select_atoms(None)
         with pytest.raises(ValueError, match="Timeseries requires at least"):
-            reader.timeseries(atoms)
+            reader.timeseries(asel=atoms)
+
+    def test_timeseries_empty_atomgroup(self, reader):
+        with pytest.warns(UserWarning,
+                          match="Empty string to select atoms, empty group returned."):
+            atoms = mda.Universe(reader.filename).select_atoms(None)
+        with pytest.raises(ValueError, match="Timeseries requires at least"):
+            reader.timeseries(atomgroup=atoms)
+
+    def test_timeseries_asel_warns_deprecation(self, reader):
+        atoms = mda.Universe(reader.filename).select_atoms("index 1")
+        with pytest.warns(DeprecationWarning, match="asel argument to"):
+            timeseries = reader.timeseries(asel=atoms, order='fac')
+
+    def test_timeseries_atomgroup(self, reader):
+        atoms = mda.Universe(reader.filename).select_atoms("index 1")
+        timeseries = reader.timeseries(atomgroup=atoms, order='fac')
+
+    def test_timeseries_atomgroup_asel_mutex(self, reader):
+        atoms = mda.Universe(reader.filename).select_atoms("index 1")
+        with pytest.raises(ValueError, match="Cannot provide both"):
+            timeseries = reader.timeseries(atomgroup=atoms, asel=atoms, order='fac')
+
 
 class MultiframeReaderTest(BaseReaderTest):
     def test_last_frame(self, ref, reader):

testsuite/MDAnalysisTests/coordinates/test_dcd.py

@@ -231,12 +231,6 @@ def test_timeseries_atomindices(indices, universe_dcd):
         assert_array_almost_equal(xyz, allframes[indices])
 
 
-def test_timeseries_empty_selection(universe_dcd):
-    with pytest.raises(ValueError):
-        asel = universe_dcd.select_atoms('name FOO')
-        universe_dcd.trajectory.timeseries(asel=asel)
-
-
 def test_reader_set_dt():
     dt = 100
     frame = 3

testsuite/MDAnalysisTests/coordinates/test_memory.py

@@ -202,6 +202,20 @@ def test_timeseries_warns_deprecation(self, reader):
                           "inclusive"):
             reader.timeseries(start=0, stop=3, step=1)
 
+    def test_timeseries_asel_warns_deprecation(self, ref, reader):
+        selection = ref.universe.atoms
+        with pytest.warns(DeprecationWarning, match="asel argument to"):
+            reader.timeseries(asel=selection)
+
+    def test_timeseries_atomgroup(self, ref, reader):
+        selection = ref.universe.atoms
+        reader.timeseries(atomgroup=selection)
+
+    def test_timeseries_atomgroup_asel_mutex(self, ref, reader):
+        selection = ref.universe.atoms
+        with pytest.raises(ValueError, match="Cannot provide both"):
+            reader.timeseries(atomgroup=selection, asel=selection)
+
 
 class TestMemoryReaderVelsForces(object):
     @staticmethod