Multi-Task GP tutorial doesn't run

The Ax Multi-Task GP tutorial (https://ax.dev/tutorials/multi_task.html) runs until the Bayesian optimization loop step 4c

runners = {
    'GP, online only': run_online_only_bo,
    'MTGP, Algorithm 1': run_mtbo,
}
iteration_objectives = {k: [] for k in runners}
iteration_constraints = {k: [] for k in runners}
for rep in range(n_reps):
    print('Running rep', rep)
    for k, r in runners.items():
        obj, con = r()
        iteration_objectives[k].append(obj)
        iteration_constraints[k].append(con)

for k, v in iteration_objectives.items():
    iteration_objectives[k] = np.array(v)
    iteration_constraints[k] = np.array(iteration_constraints[k])

At which point it fails with ValueError: status_quo is not defined for the selected trial.

Stack trace:

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-8-6f5702c98588> in <module>
      8     print('Running rep', rep)
      9     for k, r in runners.items():
---> 10         obj, con = r()
     11         iteration_objectives[k].append(obj)
     12         iteration_constraints[k].append(con)

<ipython-input-7-88fb8b2e972e> in run_mtbo()
     51             experiment=exp_multitask,
     52             data=exp_multitask.fetch_data(),
---> 53             search_space=exp_multitask.search_space,
     54         )
     55 

~/.pyenv/versions/3.7.3/envs/p3/lib/python3.7/site-packages/ax/modelbridge/factory.py in get_MTGP(experiment, data, search_space, trial_index)
    208     status_quo = experiment.trials[trial_index].status_quo
    209     if status_quo is None:
--> 210         raise ValueError("status_quo is not defined for the selected trial.")
    211     else:
    212         status_quo_features = ObservationFeatures(

ValueError: status_quo is not defined for the selected trial.

Environment:

python 3.7.3
ax-platform 0.1.6
botorch 0.1.4
gpytorch 0.3.5

[kzielnicki]

Thanks @Balandat and @sdsingh, I can verify that this runs after installing gpytorch from master 🎉

[lena-kashtelyan]

The tutorial now runs on latest stable versions of Ax + BoTorch!