# How to execute many circuits on an IBMQ backend?

I attempted to execute a list of $$3200$$ QuantumCircuits in Qiskit, each with the max_shots of $$8096$$ as follows:

ibmq_manhattan = provider.get_backend('ibmq_manhattan')
job = execute(all_qc, backend=ibmq_manhattan, shots=8096)
job_monitor(job)


and got the following response:

Job Status: job has been cancelled

Furthermore, I successfully performed the exact same execution locally using the Aer qasm_simulator. Presumably this is because there is a runtime timeout on the IBMQ backend device which is triggered as one might expect for such a large list. Is this correct? and if so how can I bypass this limitation?

This is a summary of the job on IBMQ:

If you have more circuits than what the backend allows, consider using IBMQJobManager, which will divide the circuits and collect results for you.

Checkout the backend max_experiments property. The amount of circuits in a job ( len(all_qc)) should be smaller than that.

For example, in ibmq_16_melbourne:

from qiskit import IBMQ

provider = IBMQ.get_provider(hub='ibm-q')
device = provider.get_backend('ibmq_16_melbourne')
device.configuration().max_experiments

75

• thanks for that, ibmq_manhattan has a limit of 900, however executing a single circuit took ~40s, so if I were to execute 900 then that would take about ~10 hours. I don't mind waiting, but does the backend not have an execution timeout? Sep 10, 2020 at 21:14
• Not that I'm aware of... just make sure you have your job id to retrieve your result. Sep 10, 2020 at 21:18
• will do, thanks :) Sep 10, 2020 at 21:21