Fix xr check coords (#221)

* fix check for timedelta64 in xr_check_coords

* fix time_ref_restore for datetime64 without existing ref_time

* allow np.datetime64 for _as_valid_timestamp

* update CHANGELOG.md

* add utility test

CHANGELOG.md

@@ -19,6 +19,8 @@
 
 ### fixes
 - don't inline time dependent `LCS.coordinates` [[#222]](https://github.com/BAMWelDX/weldx/pull/222)
+- fix "datetime64" passing for "timedelta64" in `xr_check_coords` [[#221]](https://github.com/BAMWelDX/weldx/pull/221)
+- fix `time_ref_restore` not working correctly if no `time_ref` was set [[#221]](https://github.com/BAMWelDX/weldx/pull/221)
 
 ## 0.2.2 (30.11.2020)
 ### added

tests/test_utility.py

@@ -354,7 +354,7 @@ def test_get_time_union(list_of_objects, time_exp):
     assert np.all(ut.get_time_union(list_of_objects) == time_exp)
 
 
-def test_xf_fill_all():
+def test_xr_fill_all():
     """Test filling along all dimensions."""
     da1 = xr.DataArray(
         np.eye(2), dims=["a", "b"], coords={"a": np.arange(2), "b": np.arange(2)}
@@ -440,6 +440,7 @@ def test_xr_check_coords(dax, ref_dict):
             ValueError,
         ),
         (_dax_check, {"d1": {"dtype": [int, str, bool]}}, TypeError),
+        (_dax_check, {"d3": {"dtype": "timedelta64"}}, TypeError),
         (_dax_check, {"d4": {"dtype": "datetime64"}}, TypeError),
         ({"d4": np.arange(4)}, {"d4": {"dtype": "int"}}, ValueError),
     ],
@@ -448,3 +449,41 @@ def test_xr_check_coords_exception(dax, ref_dict, exception_type):
     """Test weldx.utility.xr_check_coords function."""
     with pytest.raises(exception_type):
         ut.xr_check_coords(dax, ref_dict)
+
+
+def test_xr_time_ref():
+    """Test weldx accessor functions for time handling."""
+    dt = pd.TimedeltaIndex([0, 1, 2, 3], "s")
+    da1 = xr.DataArray(
+        data=np.ones(4),
+        dims=["time"],
+        coords={"time": dt},
+    )
+
+    da1.time.attrs = {"A": "B"}
+
+    # non changing operations
+    da = da1.weldx.time_ref_unset()
+    assert da1.identical(da)
+    da = da1.weldx.time_ref_restore()
+    assert da1.identical(da)
+
+    t0 = pd.Timestamp("2021-01-01")
+    da1.weldx.time_ref = t0
+    da = da1.weldx.time_ref_unset()
+    assert np.all(da.time.data == (dt + t0))
+
+    da = da.weldx.reset_reference_time(pd.Timestamp("2021-01-01 00:00:01"))
+    assert np.all(da.time.data == pd.TimedeltaIndex([-1, 0, 1, 2], "s"))
+
+    da2 = xr.DataArray(
+        data=np.ones(4),
+        dims=["time"],
+        coords={"time": t0 + dt},
+    )
+    da2 = da2.weldx.time_ref_restore()
+    assert np.all(da2.time.data == pd.TimedeltaIndex([0, 1, 2, 3], "s"))
+    assert da2.time.attrs["time_ref"] == t0
+
+    da2.weldx.time_ref = t0
+    assert da2.time.attrs["time_ref"] == t0

weldx/utility.py

@@ -729,10 +729,8 @@ def _check_dtype(var_dtype, ref_dtype: dict) -> bool:
     if var_dtype != np.dtype(ref_dtype):
         if isinstance(ref_dtype, str):
             if (
-                "timedelta64" in ref_dtype
-                or "datetime64" in ref_dtype
-                and np.issubdtype(var_dtype, np.dtype(ref_dtype))
-            ):
+                "timedelta64" in ref_dtype or "datetime64" in ref_dtype
+            ) and np.issubdtype(var_dtype, np.dtype(ref_dtype)):
                 return True
 
         if not (
@@ -978,20 +976,20 @@ def xr_interp_coordinates_in_time(
     return da
 
 
-def _as_valid_timestamp(value: Union[pd.Timestamp, str]) -> pd.Timestamp:
+def _as_valid_timestamp(value: Union[pd.Timestamp, np.datetime64, str]) -> pd.Timestamp:
     """Create a valid (by convention) Timestamp object or raise TypeError.
 
     Parameters
     ----------
-    value: pandas.Timestamp or str
+    value: pandas.Timestamp, np.datetime64 or str
         Value to convert to `pd.Timestamp`.
 
     Returns
     -------
     pandas.Timestamp
 
     """
-    if isinstance(value, str):
+    if isinstance(value, (str, np.datetime64)):
         value = pd.Timestamp(value)
     if isinstance(value, pd.Timestamp):  # catch NaT from empty str.
         return value
@@ -1039,10 +1037,16 @@ def time_ref_unset(self) -> xr.DataArray:
     def time_ref_restore(self) -> xr.DataArray:
         """Convert DatetimeIndex back to TimedeltaIndex + reference Timestamp."""
         da = self._obj.copy()
-        time_ref = da.weldx.time_ref
-        if time_ref and is_datetime64_dtype(da.time):
+        if "time" not in da.coords:
+            return da
+
+        if is_datetime64_dtype(da.time):
+            time_ref = da.weldx.time_ref
+            if time_ref is None:
+                time_ref = pd.Timestamp(da.time.data[0])
             da["time"] = pd.DatetimeIndex(da.time.data) - time_ref
             da.time.attrs = self._obj.time.attrs  # restore old attributes !
+            da.time.attrs["time_ref"] = time_ref
         return da
 
     def reset_reference_time(self, time_ref_new: pd.Timestamp) -> xr.DataArray:
@@ -1053,7 +1057,7 @@ def reset_reference_time(self, time_ref_new: pd.Timestamp) -> xr.DataArray:
         return da
 
     @property
-    def time_ref(self) -> pd.Timestamp:
+    def time_ref(self) -> Union[pd.Timestamp, None]:
         """Get the time_ref value or `None` if not set."""
         da = self._obj
         if "time" in da.coords: