result.get_counts(schedule) raises QiskitError

Information

• Qiskit Terra version: master
• Python version:
• Operating system:

What is the current behavior?

In qiskit-terra qiskit.result.result.Result._get_experiment, there is an assumption that Schedules always have names. This isn’t true, so trying to get results from a batch job execution gives an error.

Steps to reproduce the problem

When I run

job = execute(list_of_schedules, backend)
result = job.result()
result.get_counts(list_of_schedules[0])

I get the error:

QiskitError: 'Data for experiment "None" could not be found.'

because of these lines:

        # Key is a QuantumCircuit/Schedule or str: retrieve result by name.
        if isinstance(key, (QuantumCircuit, Schedule)):
            key = key.name

where schedule.name is None.

What is the expected behavior?

I should get my data from the result for the given Schedule.

Suggested solutions

We could remove the option to get results by Schedule as a key, and instead only take the index of the experiment for Schedules. We could force Schedules to have a name, but that adds unnecessary work on the user’s side, so I don’t prefer that. We could try to find a different way to match Schedules to their results rather than by Schedule name.

Extra info

This is how I actually made my batch of schedules.

# dt ~= 3.5e-9 from backend
experiments = []
for t in np.round(np.linspace(500e-9 / dt, 20_000e-9 / dt, 40)):
    schedule = Schedule()
    schedule += x_pulse << int(t)    # x_pulse and measure from CmdDef
    schedule += measure << int(t) + x_pulse.duration
    experiments.append(schedule)

[willhbang]

@lcapelluto waiting on review in my PR, i’ll bump it

[lcapelluto]

afaik, yes