Issues with UnivariateProbabilitySimulator and missing values/scale y

[jason-bentley]

Describe the bug
The current UnivariateProbabilitySimulator() appears to have two issues:

1. The simulator fails to create partitions when the feature being simulated contains missing values - ValueError: cannot convert float NaN to integer
2. If the feature does not have missing values an error an error is thrown when trying to work out the scale for y - TypeError: '>' not supported between instances of 'float' and 'method'

To Reproduce
To reproduce these errors please got to the branch: https://github.com/BCG-Gamma/facet/tree/docs/notebook_updates
and within the sphinx > source > tutorial folder run the notebook: https://github.com/BCG-Gamma/facet/blob/docs/notebook_updates/sphinx/source/tutorial/Prediabetes_classification_with_Facet.ipynb

Expected behavior
In both cases I expect to be able to get a complete figure with simulated trend and CIs for a feature displayed correctly.

Screenshots

First error:

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-60-ea5a7119572e> in <module>
      2 simulator = UnivariateProbabilitySimulator(crossfit=ranker.best_model_crossfit, n_jobs=-1)
      3 partitioner = ContinuousRangePartitioner()
----> 4 univariate_simulation = simulator.simulate_feature(name=sim_feature, partitioner=partitioner)

C:\Projects\facet\facet\src\facet\simulation\_simulation.py in simulate_feature(self, name, partitioner)
    182             raise NotImplementedError("multi-output simulations are not supported")
    183 
--> 184         simulation_values = partitioner.fit(sample.features.loc[:, name]).partitions()
    185         simulation_results = self._aggregate_simulation_results(
    186             results_per_split=self._simulate_feature_with_values(

C:\Projects\facet\facet\src\facet\simulation\partition\_partition.py in fit(self, values, lower_bound, upper_bound, **fit_params)
    202         # calculate the step count based on the maximum number of partitions,
    203         # rounded to the next-largest rounded value ending in 1, 2, or 5
--> 204         self._step = step = self._step_size(lower_bound, upper_bound)
    205 
    206         # calculate centre values of the first and last partition;

C:\Projects\facet\facet\src\facet\simulation\partition\_partition.py in _step_size(self, lower_bound, upper_bound)
    334     def _step_size(self, lower_bound: float, upper_bound: float) -> float:
    335         return RangePartitioner._ceil_step(
--> 336             (upper_bound - lower_bound) / (self.max_partitions - 1)
    337         )
    338 

C:\Projects\facet\facet\src\facet\simulation\partition\_partition.py in _ceil_step(step)
    294             raise ValueError("arg step must be positive")
    295 
--> 296         return min(10 ** math.ceil(math.log10(step * m)) / m for m in [1, 2, 5])
    297 
    298     @staticmethod

C:\Projects\facet\facet\src\facet\simulation\partition\_partition.py in <genexpr>(.0)
    294             raise ValueError("arg step must be positive")
    295 
--> 296         return min(10 ** math.ceil(math.log10(step * m)) / m for m in [1, 2, 5])
    297 
    298     @staticmethod

ValueError: cannot convert float NaN to integer

Second error:

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-58-22d13aac8dd5> in <module>
----> 1 SimulationDrawer().draw(data=univariate_simulation, title=sim_feature)

C:\Projects\facet\facet\src\facet\simulation\viz\_draw.py in draw(self, data, title)
     73         if title is None:
     74             title = f"Simulation: {data.feature}"
---> 75         super().draw(data=data, title=title)
     76 
     77     @classmethod

C:\Projects\facet\pytools\src\pytools\viz\_viz.py in draw(self, data, title)
    104             # noinspection PyProtectedMember
    105             style._drawing_start(title)
--> 106             self._draw(data)
    107             # noinspection PyProtectedMember
    108             style._drawing_finalize()

C:\Projects\facet\facet\src\facet\simulation\viz\_draw.py in _draw(self, data)
     96             partitions=simulation_series.partitions,
     97             frequencies=simulation_series.frequencies,
---> 98             is_categorical_feature=data.partitioner.is_categorical,
     99         )
    100 

C:\Projects\facet\facet\src\facet\simulation\viz\_style.py in draw_uplift(self, feature, target, values_label, values_median, values_min, values_max, values_baseline, percentile_lower, percentile_upper, partitions, frequencies, is_categorical_feature)
    178 
    179         # add a horizontal line at y=0
--> 180         ax.axhline(y=values_baseline, linewidth=0.5)
    181 
    182         # remove the top and right spines

C:\Anaconda3\envs\facet-develop\lib\site-packages\matplotlib\axes\_axes.py in axhline(self, y, xmin, xmax, **kwargs)
    860         self._process_unit_info(ydata=y, kwargs=kwargs)
    861         yy = self.convert_yunits(y)
--> 862         scaley = (yy < ymin) or (yy > ymax)
    863 
    864         trans = self.get_yaxis_transform(which='grid')

TypeError: '>' not supported between instances of 'float' and 'method'

Desktop (please complete the following information):

• Windows
• Chrome