API documentation

Module for conversion from tket primitives to Qulacs primitives.

class pytket.extensions.qulacs.QulacsBackend(result_type='state_vector')[source]

Backend for running simulations on the Qulacs simulator


Return a CircuitStatus reporting the status of the circuit execution corresponding to the ResultHandle

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A suggested compilation pass that will will, if possible, produce an equivalent circuit suitable for running on this backend.

At a minimum it will ensure that compatible gates are used and that all two- qubit interactions are compatible with the backend’s qubit architecture. At higher optimisation levels, further optimisations may be applied.

This is a an abstract method which is implemented in the backend itself, and so is tailored to the backend’s requirements.


optimisation_level (int, optional) –

The level of optimisation to perform during compilation.

  • Level 0 does the minimum required to solves the device constraints, without any optimisation.

  • Level 1 additionally performs some light optimisations.

  • Level 2 (the default) adds more computationally intensive optimisations that should give the best results from execution.


Compilation pass guaranteeing required predicates.

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process_circuits(circuits, n_shots=None, valid_check=True, **kwargs)[source]

Submit circuits to the backend for running. The results will be stored in the backend’s result cache to be retrieved by the corresponding get_<data> method.

If the postprocess keyword argument is set to True, and the backend supports the feature (see supports_contextual_optimisation()), then contextual optimisatioons are applied before running the circuit and retrieved results will have any necessary classical postprocessing applied. This is not enabled by default.

Use keyword arguments to specify parameters to be used in submitting circuits See specific Backend derived class for available parameters, from the following list:

  • seed: RNG seed for simulators

  • postprocess: if True, apply contextual optimisations

Note: If a backend is reused many times, the in-memory results cache grows indefinitely. Therefore, when processing many circuits on a statevector or unitary backend (whose results may occupy significant amounts of memory), it is advisable to run Backend.empty_cache() after each result is retrieved.

  • circuits (Sequence[Circuit]) – Circuits to process on the backend.

  • n_shots (Optional[Union[int, Iterable[int]], optional) – Number of shots to run per circuit. Optionally, this can be a list of shots specifying the number of shots for each circuit separately. None is to be used for state/unitary simulators. Defaults to None.

  • valid_check (bool, optional) – Explicitly check that all circuits satisfy all required predicates to run on the backend. Defaults to True


Handles to results for each input circuit, as an interable in the same order as the circuits.

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A single compilation pass that when run converts all gates in a Circuit to an OpType supported by the Backend (ignoring architecture constraints).


Compilation pass that converts gates to primitives supported by Backend.

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property backend_info: BackendInfo | None

Retrieve all Backend properties in a BackendInfo object, including device architecture, supported gate set, gate errors and other hardware-specific information.


The BackendInfo describing this backend if it exists.

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property required_predicates: List[Predicate]

The minimum set of predicates that a circuit must satisfy before it can be successfully run on this backend.


Required predicates.

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pytket.extensions.qulacs.tk_to_qulacs(circuit, reverse_index=False, replace_implicit_swaps=False)[source]

Convert a pytket circuit to a qulacs circuit object.

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