issues: 324740017

Code Sample, a copy-pastable example if possible

Consider a simple working example of converting an xarray dataset to holoviews for plotting:

python ref_date = '1981-01-01' ds = xr.DataArray([1, 2, 3], dims=['time'], coords={'time': ('time', [1, 2, 3], {'units': 'days since %s' % ref_date})} ).to_dataset(name='foo') with xr.set_options(enable_cftimeindex=True): ds = xr.decode_cf(ds) print(ds) hv_ds = hv.Dataset(ds) hv_ds.to(hv.Curve)

This gives <xarray.Dataset> Dimensions: (time: 3) Coordinates: * time (time) datetime64[ns] 1981-01-02 1981-01-03 1981-01-04 Data variables: foo (time) int64 ... and

Problem description

Now change ref_date = '0181-01-01' (or anything outside of the valid range for regular pandas datetime index). We get a beautiful new cftimeindex <xarray.Dataset> Dimensions: (time: 3) Coordinates: * time (time) object 0181-01-02 00:00:00 0181-01-03 00:00:00 ... Data variables: foo (time) int64 ...

but holoviews / bokeh doesn't like it ``` /opt/conda/lib/python3.6/site-packages/xarray/coding/times.py:132: SerializationWarning: Unable to decode time axis into full numpy.datetime64 objects, continuing using dummy cftime.datetime objects instead, reason: dates out of range enable_cftimeindex) /opt/conda/lib/python3.6/site-packages/xarray/coding/variables.py:66: SerializationWarning: Unable to decode time axis into full numpy.datetime64 objects, continuing using dummy cftime.datetime objects instead, reason: dates out of range return self.func(self.array[key])

---

TypeError Traceback (most recent call last) /opt/conda/lib/python3.6/site-packages/IPython/core/formatters.py in call(self, obj, include, exclude) 968 969 if method is not None: --> 970 return method(include=include, exclude=exclude) 971 return None 972 else:

/opt/conda/lib/python3.6/site-packages/holoviews/core/dimension.py in repr_mimebundle(self, include, exclude) 1229 combined and returned. 1230 """ -> 1231 return Store.render(self) 1232 1233

/opt/conda/lib/python3.6/site-packages/holoviews/core/options.py in render(cls, obj) 1287 data, metadata = {}, {} 1288 for hook in hooks: -> 1289 ret = hook(obj) 1290 if ret is None: 1291 continue

/opt/conda/lib/python3.6/site-packages/holoviews/ipython/display_hooks.py in pprint_display(obj) 278 if not ip.display_formatter.formatters['text/plain'].pprint: 279 return None --> 280 return display(obj, raw_output=True) 281 282

/opt/conda/lib/python3.6/site-packages/holoviews/ipython/display_hooks.py in display(obj, raw_output, **kwargs) 248 elif isinstance(obj, (CompositeOverlay, ViewableElement)): 249 with option_state(obj): --> 250 output = element_display(obj) 251 elif isinstance(obj, (Layout, NdLayout, AdjointLayout)): 252 with option_state(obj):

/opt/conda/lib/python3.6/site-packages/holoviews/ipython/display_hooks.py in wrapped(element) 140 try: 141 max_frames = OutputSettings.options['max_frames'] --> 142 mimebundle = fn(element, max_frames=max_frames) 143 if mimebundle is None: 144 return {}, {}

/opt/conda/lib/python3.6/site-packages/holoviews/ipython/display_hooks.py in element_display(element, max_frames) 186 return None 187 --> 188 return render(element) 189 190

/opt/conda/lib/python3.6/site-packages/holoviews/ipython/display_hooks.py in render(obj, kwargs) 63 renderer = renderer.instance(fig='png') 64 ---> 65 return renderer.components(obj, kwargs) 66 67

/opt/conda/lib/python3.6/site-packages/holoviews/plotting/bokeh/renderer.py in components(self, obj, fmt, comm, kwargs) 257 # Bokeh has to handle comms directly in <0.12.15 258 comm = False if bokeh_version < '0.12.15' else comm --> 259 return super(BokehRenderer, self).components(obj,fmt, comm, kwargs) 260 261

/opt/conda/lib/python3.6/site-packages/holoviews/plotting/renderer.py in components(self, obj, fmt, comm, **kwargs) 319 plot = obj 320 else: --> 321 plot, fmt = self._validate(obj, fmt) 322 323 widget_id = None

/opt/conda/lib/python3.6/site-packages/holoviews/plotting/renderer.py in _validate(self, obj, fmt, kwargs) 218 if isinstance(obj, tuple(self.widgets.values())): 219 return obj, 'html' --> 220 plot = self.get_plot(obj, renderer=self, kwargs) 221 222 fig_formats = self.mode_formats['fig'][self.mode]

/opt/conda/lib/python3.6/site-packages/holoviews/plotting/bokeh/renderer.py in get_plot(self_or_cls, obj, doc, renderer) 150 doc = Document() if self_or_cls.notebook_context else curdoc() 151 doc.theme = self_or_cls.theme --> 152 plot = super(BokehRenderer, self_or_cls).get_plot(obj, renderer) 153 plot.document = doc 154 return plot

/opt/conda/lib/python3.6/site-packages/holoviews/plotting/renderer.py in get_plot(self_or_cls, obj, renderer) 205 init_key = tuple(v if d is None else d for v, d in 206 zip(plot.keys[0], defaults)) --> 207 plot.update(init_key) 208 else: 209 plot = obj

/opt/conda/lib/python3.6/site-packages/holoviews/plotting/plot.py in update(self, key) 511 def update(self, key): 512 if len(self) == 1 and ((key == 0) or (key == self.keys[0])) and not self.drawn: --> 513 return self.initialize_plot() 514 item = self.getitem(key) 515 self.traverse(lambda x: setattr(x, '_updated', True))

/opt/conda/lib/python3.6/site-packages/holoviews/plotting/bokeh/element.py in initialize_plot(self, ranges, plot, plots, source) 729 if not self.overlaid: 730 self._update_plot(key, plot, style_element) --> 731 self._update_ranges(style_element, ranges) 732 733 for cb in self.callbacks:

/opt/conda/lib/python3.6/site-packages/holoviews/plotting/bokeh/element.py in _update_ranges(self, element, ranges) 498 if not self.drawn or xupdate: 499 self._update_range(x_range, l, r, xfactors, self.invert_xaxis, --> 500 self._shared['x'], self.logx, streaming) 501 if not self.drawn or yupdate: 502 self._update_range(y_range, b, t, yfactors, self.invert_yaxis,

/opt/conda/lib/python3.6/site-packages/holoviews/plotting/bokeh/element.py in _update_range(self, axis_range, low, high, factors, invert, shared, log, streaming) 525 updates = {} 526 if low is not None and (isinstance(low, util.datetime_types) --> 527 or np.isfinite(low)): 528 updates['start'] = (axis_range.start, low) 529 if high is not None and (isinstance(high, util.datetime_types)

TypeError: ufunc 'isfinite' not supported for the input types, and the inputs could not be safely coerced to any supported types according to the casting rule ''safe'' ```

Similar but slightly different errors arise for different holoviews types (e.g. hv.Image) and contexts (using time as a holoviews kdim).

Expected Output

This should work.

I'm not sure if this is really an xarray problem. Maybe it needs a fix in holoviews (or bokeh). But I'm raising it here first since clearly we have introduced this new wrinkle in the stack. Cc'ing @philippjfr since he is the expert on all things holoviews.

Output of xr.show_versions()

INSTALLED VERSIONS ------------------ commit: None python: 3.6.3.final.0 python-bits: 64 OS: Linux OS-release: 4.4.111+ machine: x86_64 processor: x86_64 byteorder: little LC_ALL: en_US.UTF-8 LANG: en_US.UTF-8 LOCALE: en_US.UTF-8 xarray: 0.10.4 pandas: 0.23.0 numpy: 1.14.3 scipy: 1.1.0 netCDF4: 1.4.0 h5netcdf: None h5py: None Nio: None zarr: 2.2.0 bottleneck: None cyordereddict: None dask: 0.17.5 distributed: 1.21.8 matplotlib: 2.2.2 cartopy: None seaborn: None setuptools: 39.0.1 pip: 10.0.1 conda: 4.3.34 pytest: 3.5.1 IPython: 6.3.1 sphinx: None