How to pass shot number to Quantum tasks within AwsQuantumJob correctly

Question

Hi there,

I am trying to run a Hybrid job and I am not sure how to pass the shot number correctly to the tasks within the hybrid job. My script works as expected on SV1 simulators but as soon as I switch to IQM hardware, I obtain the following error:

botocore.errorfactory.ValidationException: An error occurred (ValidationException) when calling the CreateQuantumTask operation: shots must be between #[1, 20000]

The relevant parts of my scripts are the following:

1) I initialize the hybrid job
`device_parameters = {
    'name' : 'braket.aws.qubit',
    'device_arn' : 'arn:aws:braket:eu-north-1::device/qpu/iqm/Garnet',
    'shots' = 10
}`

`job = AwsQuantumJob.create(
      device = device_parameters["device_arn"],
      source_module="A",
      entry_point="A.script:run",
      .... 
)
`

2) Within the run function, I define a qnode function
`def qnode_func(device_parameters, weights):
      dev = qml.device(**device_parameters, wires=n_qubits)
      qnode = qml.QNode(qnode_fn, dev, diff_method=None, interface="jax")
      return qnode(weights)`

3) I call the qnode_func as
`samples = qnode_func(device_parameters, weights)`

----------------------------------------------------------------------------------------------------------------

Where would the correct location be to set the shot number? Already within AwsQuantumJob.create(...), for example by passing a device that has a shot number configured?

It seems that I am creating a new device in qnode_func. Should I somehow call the device of the AwsQuantumJob instead?

emkesslerAWS · Answer

Hi there, in PennyLane the number of shots is specified in [`qml.device`](https://docs.pennylane.ai/en/stable/code/api/pennylane.device.html), in your example something like

```
dev = qml.device("braket.aws.qubit", device_arn='arn:aws:braket:eu-north-1::device/qpu/iqm/Garnet', wires=n_qubits, *shots=10*)
```

With Hybrid Jobs you can run your algorithm script on a classical instance managed by Braket (instead of on your laptop for instance). The reason you pass the device ARN into the `AwsQuantumJob` call is to ensure your job will have priority access (meaning each task from your algorithm will jump to the front of the queue) to the device for the duration of your algorithm. But you don't need to specify any details, such as, shots at that point.

How to pass shot number to Quantum tasks within AwsQuantumJob correctly

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