Batch Jobs

This notebook contains an example of how to perform batch submissions on H-Series emulators and quantum computers via pytket.

The batch feature on H-Series backends gives users the ability to create “ad-hoc” reservations. Circuits submitted together in a batch will run at one time. The benefit to users is that once a batch hits the front of the queue, jobs in a batch will run uninterrupted until they are completed.

Once a batch is submitted, jobs can continue to be added to the batch, ending either when the user signifies the end of a batch or after 1 minute of inactivity.

Batches cannot exceed the maximum limit of 2,000 H-System Quantum Credits (HQCs) total. If the total HQCs for jobs in a batch hit this limit or a smaller limit set by the user, those jobs will not be cancelled. Instead, they will continue to run as regular jobs in the queue instead of as a batch.

Currently only the quantum computer and emulator targets support the batching feature. Batching is not supported on the syntax checkers.

For more information on using this feature in pytket-quantinuum, see Batching.

To start a batch, use the start_batch function, specifying the max_batch_cost in HQCs to enforce.

from pytket.extensions.quantinuum import QuantinuumBackend
from pytket.circuit.display import render_circuit_jupyter
from pytket.circuit import Circuit, fresh_symbol

machine = "H1-1E"
n_shots = 100
max_batch_cost = 100

Set up Bell State

circuit = Circuit(2, name="Bell State")
circuit.H(0)
circuit.CX(0, 1)
circuit.measure_all()

backend = QuantinuumBackend(device_name=machine)

compiled_circuit = backend.get_compiled_circuit(circuit, optimisation_level=0)
batch1 = backend.start_batch(
    max_batch_cost=max_batch_cost, circuit=compiled_circuit, n_shots=n_shots
)

Additional jobs can be added to the batch using the add_to_batch function. The end of a batch can optionally be specified with the batch_end flag.

batch2 = backend.add_to_batch(batch1, compiled_circuit, n_shots=n_shots)
batch3 = backend.add_to_batch(batch1, compiled_circuit, n_shots=n_shots, batch_end=True)

The status for the batch jobs can be checked once submitted.

handle_list = [batch1, batch2, batch3]
status_list = [backend.circuit_status(h) for h in handle_list]

status_list

Results for batch submissions can be returned using get_results (note the plural).

results = backend.get_results(handle_list)
for result in results:
    print(result.get_counts())