Jobs run on the IonQ "ideal" simulator provide deterministic results, so for these jobs, the IonQ API returns results as histogram probabilities instead of measurement counts. However, currently, there is no way to pass just raw probability data to GateModelResultData (#785). To patch this, we've added an arbitrary default shots value to IonQ.submit:

so that the IonQJob.result() method can construct measurement counts data based on the returned probabilities together with that shots value:

For sequential job submission and results retrieval this works fine:

from qbraid.runtime import IonQJob, IonQProvider

provider = IonQProvider(api_key="...")

device = provider.get_device("simulator")

program = """
OPENQASM 2.0;
qreg q[2];
h q[0];
cx q[0],q[1];
cx q[1],q[0];
"""

job = device.run(program)

# Getting the result directly from the job object created from device.run
# works fine because we carry over arbitrary placeholder value for shots
print(job._cache_metadata.get("shots")) # 100

result = job.result()

However, this arbitrary shots value is not used by the IonQ "ideal" simulator, and therefore is not stored anywhere other than locally within that initial IonQJob instance. So if you then create a new job instance from the job ID, the result() method fails with a ValueError because there is no stored value for "shots."

job = IonQJob(job.id, session=provider.session)

print(job._cache_metadata.get("shots")) # None

result = job.result()
# File ~/.../qBraid/qbraid/runtime/ionq/job.py:86, in IonQJob._get_counts(result)
#      84 probs_dec_str: Optional[dict[str, float]] = result.get("probabilities")
#      85 if shots is None or probs_dec_str is None:
# ---> 86     raise ValueError("Missing shots or probabilities in result data.")
#      87 probs_dec = {int(key): value for key, value in probs_dec_str.items()}
#      88 probs_normal = normalize_counts(probs_dec)

# ValueError: Missing shots or probabilities in result data.

TODO

• Close related issue Enhance GateModelResultData to support direct probability data #785
• Remove placeholder (default) shots value from IonQDevice.submit()
• Revise IonQJob.result() to pass probability data directly to GateModelResultData, and only construct measurement counts data from probabilities if shots > 0.