Grid search produces `IndexError: pop from empty list`

[sgbaird]

Algorithm: Grid [repetition 1]
[INFO] Loading emulator using a BayesNeuralNet model for the dataset photo_pce10...
[INFO] Last parameter being provided - there will not be any more available samples in the grid.
---------------------------------------------------------------------------
IndexError                                Traceback (most recent call last)
[<ipython-input-7-f36bc3f1915d>](https://localhost:8080/#) in <module>
     36         campaign=Campaign(),  # store results in a new campaign,
     37         database=database,    # but use the same database to store campaign;
---> 38         num_iter=64,         # run benchmark for num_iter iterations
     39     )
     40     elapsed_time = time() - start_time

4 frames
[/usr/local/lib/python3.7/dist-packages/olympus/olympus.py](https://localhost:8080/#) in run(self, planner, dataset, model, goal, campaign, database, num_iter)
     55             planner=planner_, emulator=emulator, campaign=campaign, database=database,
     56         )
---> 57         self.evaluator.optimize(num_iter=num_iter)
     58 
     59     def run_analytic(

[/usr/local/lib/python3.7/dist-packages/olympus/evaluators/evaluator.py](https://localhost:8080/#) in optimize(self, num_iter)
     66             # NOTE: now we get 1 param at a time, a possible future expansion is
     67             #       to return batches
---> 68             params = self.planner.recommend(observations=self.campaign.observations)
     69 
     70             # get measurement from emulator/surface

[/usr/local/lib/python3.7/dist-packages/olympus/planners/abstract_planner.py](https://localhost:8080/#) in recommend(self, observations, return_as)
    130         """
    131         self.tell(observations)
--> 132         return self.ask(return_as=return_as)
    133 
    134     def optimize(self, emulator, num_iter=1, verbose=False):

[/usr/local/lib/python3.7/dist-packages/olympus/planners/abstract_planner.py](https://localhost:8080/#) in ask(self, return_as)
     95 
     96         self.num_generated += 1
---> 97         param_vector = self._ask()
     98 
     99         # check that the parameters suggested are within the bounds of our param_space

[/usr/local/lib/python3.7/dist-packages/olympus/planners/planner_grid/wrapper_grid.py](https://localhost:8080/#) in _ask(self)
    126         if self.grid_created is False:
    127             self._create_grid()
--> 128         param = self.samples.pop(0)
    129 
    130         if len(self.samples) == 0:

IndexError: pop from empty list

Reproducer Colab Notebook