def __init__(self, backend: BaseBackend, optimisation_level: int = 1):
"""Identifies a Qiskit backend and provides the corresponding default
compilation pass from pytket as a
:py:class:`qiskit.transpiler.TransformationPass`.
:param backend: The Qiskit backend to target. Accepts Aer or IBMQ backends.
:type backend: BaseBackend
:param optimisation_level: The level of optimisation to perform during
compilation. Level 0 just solves the device constraints without
optimising. Level 1 additionally performs some light optimisations.
Level 2 adds more intensive optimisations that can increase compilation
time for large circuits. Defaults to 1.
:type optimisation_level: int, optional
"""
if not isinstance(backend, BaseBackend):
raise ValueError("Requires BaseBackend instance")
if isinstance(backend._provider, AerProvider):
tk_backend = self._aer_backend_map[type(backend).__name__]()
elif isinstance(backend._provider, AccountProvider):
tk_backend = IBMQBackend(backend.name())
else:
raise NotImplementedError(
"This backend provider is not supported.")
super().__init__(
tk_backend.default_compilation_pass(optimisation_level))
def create_from_backend(cls, backend: BaseBackend):
"""Initialize a class with backend information provided by provider.
Args:
backend: Backend object.
Returns:
OpenPulseBackendInfo: New configured instance.
"""
configuration = backend.configuration()
defaults = backend.defaults()
# load name
name = backend.name()
# load cycle time
dt = configuration.dt
# load frequencies
chan_freqs = dict()
chan_freqs.update({
pulse.DriveChannel(qind): freq
for qind, freq in enumerate(defaults.qubit_freq_est)
})
chan_freqs.update({
pulse.MeasureChannel(qind): freq
for qind, freq in enumerate(defaults.meas_freq_est)
})
for qind, u_lo_mappers in enumerate(configuration.u_channel_lo):
temp_val = .0 + .0j
for u_lo_mapper in u_lo_mappers:
temp_val += defaults.qubit_freq_est[
u_lo_mapper.q] * u_lo_mapper.scale
chan_freqs[pulse.ControlChannel(qind)] = temp_val.real
# load qubit channel mapping
qubit_channel_map = defaultdict(list)
for qind in range(configuration.n_qubits):
qubit_channel_map[qind].append(configuration.drive(qubit=qind))
qubit_channel_map[qind].append(configuration.measure(qubit=qind))
for tind in range(configuration.n_qubits):
try:
qubit_channel_map[qind].extend(
configuration.control(qubits=(qind, tind)))
except BackendConfigurationError:
pass
return OpenPulseBackendInfo(name=name,
dt=dt,
channel_frequency_map=chan_freqs,
qubit_channel_map=qubit_channel_map)
