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I am interested to know whether there is a quick and elegant way of increasing the number of shots (more than 8192 shots) on IBM hardware when running variational algorithms like VQE or QAOA.

I know that within Qiskit, I can specify: backend._configuration.max_shots= shots to change the number of max_shots but this only works for simulator. I can't increase the shots parameter to go over 8192 shots when I set my backend as one of the real hardware. That is, if I specify the following:

hardware_backend = provider.get_backend('ibmq_valencia ')
maxshots = 20000
hardware_backend._configuration.max_shots= maxshots
quantum_instance = QuantumInstance(hardware_backend, shots = maxshots, initial_layout = None,
                                   optimization_level = 3)

then upon executing the circuit, I will have an error message:

Error is : The number of shots in the Qobj (20000) is higher than the number of shots supported by the device (8192).

Is there a quick and elegant way to overcome this issue within Qiskit? Thank you!

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According to my knowledge, 8192 is a maximum of shots. I think that the reason is fair timesharing as nowadays there are many users of IBM Q.

To get better results from VQE, I can only recommend to run your task several times and then pick up the best solution, i.e. the one wiht the lowest (highest) value of the optimized function.

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    $\begingroup$ I am interested to increase the shots in each evaluation to increase the accuracy of the expectation. To get within the chemical precision, one would need in the order of million shots.. I am just trying to increase my shots to says 100,000 and see how thing goes first. What I can do is to write my own VQE function where I can run multiple jobs and combine the results but I am feeling a little lazy about it :) $\endgroup$
    – KAJ226
    Commented Dec 23, 2020 at 16:46
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    $\begingroup$ @KAJ226: I understood. However, it seems that there are limitation imposed by IBM. Maybe, there is such possibility in commercial version of IBM Q.... $\endgroup$
    – Martin Vesely
    Commented Dec 24, 2020 at 7:30
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    $\begingroup$ Like you said, 8192 shots is the max shots threshold... and there is just no way around it. So I decided to stop being lazy and write my own VQE function and to not use VQE module within Aqua to create more flexibility. I understand that the limitation on number of shots and circuits must be imposed to prevent someone from abusing the system. But I think we can agree that shots counts should play an effect in how precise your converged result is in variational quantum algorithms.. It should scales as $O(1/ \epsilon^2)$ to be more specific. Then there is the noise problem.. :( $\endgroup$
    – KAJ226
    Commented Jan 20, 2021 at 20:27

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