def get_backend(
self,
name: str = None,
instance: Optional[str] = None,
**kwargs: Any,
) -> Backend:
"""Return a single backend matching the specified filtering.
Args:
name (str): Name of the backend.
instance: The provider in the hub/group/project format.
**kwargs: Dict used for filtering.
Returns:
Backend: a backend matching the filtering.
Raises:
QiskitBackendNotFoundError: if no backend could be found or
more than one backend matches the filtering criteria.
IBMProviderValueError: If only one or two parameters from `hub`, `group`,
`project` are specified.
"""
# pylint: disable=arguments-differ
backends = self.backends(name, instance=instance, **kwargs)
if len(backends) > 1:
raise QiskitBackendNotFoundError(
"More than one backend matches the criteria")
if not backends:
raise QiskitBackendNotFoundError("No backend matches the criteria")
return backends[0]
def backends(self, name=None, filters=None, **kwargs):
"""Return a list of backends matching the name
Parameters
----------
name : str, optional
name of the backend, by default None
filters : callable, optional
Filtering conditions, as callable, by default None
Returns
-------
list[BackendV1]
A list of backend instances matching the condition
"""
backends = list(self._backends.values())
if name:
try:
backends = [self._backends[name]]
except LookupError:
raise QiskitBackendNotFoundError(
"The '{}' backend is not installed in your system.".format(name)
)
return backends
def _get_hgp(
self,
instance: Optional[str] = None,
backend_name: Optional[str] = None,
) -> HubGroupProject:
"""Return an instance of `HubGroupProject`.
This function also allows to find the `HubGroupProject` that contains a backend
`backend_name`.
Args:
instance: The hub/group/project to use.
backend_name: Name of the IBM Quantum backend.
Returns:
An instance of `HubGroupProject` that matches the specified criteria or the default.
Raises:
IBMInputValueError: If no hub/group/project matches the specified criteria,
or if the input value is in an incorrect format.
QiskitBackendNotFoundError: If backend cannot be found.
"""
if instance:
_ = from_instance_format(instance) # Verify format
if instance not in self._hgps:
raise IBMInputValueError(
f"Hub/group/project {instance} "
"could not be found for this account.")
if backend_name and not self._hgps[instance].backend(backend_name):
raise QiskitBackendNotFoundError(
f"Backend {backend_name} cannot be found in "
f"hub/group/project {instance}")
return self._hgps[instance]
if not backend_name:
return list(self._hgps.values())[0]
for hgp in self._hgps.values():
if hgp.backend(backend_name):
return hgp
raise QiskitBackendNotFoundError(
f"Backend {backend_name} cannot be found in any"
f"hub/group/project for this account.")
def get_backend(self, name=None, **kwargs):
backend = self._backends[0]
if name:
filtered_backends = [backend for backend in self._backends if backend.name() == name]
if not filtered_backends:
raise QiskitBackendNotFoundError()
backend = filtered_backends[0]
return backend
def get_backend(self, name=None, **kwargs):
"""Return a single backend matching the specified filtering.
Args:
name (str): name of the backend.
**kwargs: dict used for filtering.
Returns:
Backend: a backend matching the filtering.
Raises:
QiskitBackendNotFoundError: if no backend could be found or
more than one backend matches the filtering criteria.
"""
backends = self.backends(name, **kwargs)
if len(backends) > 1:
raise QiskitBackendNotFoundError(
'More than one backend matches criteria.')
if not backends:
raise QiskitBackendNotFoundError('No backend matches criteria.')
return backends[0]
def get_backend(self, name=None, **kwargs):
"""Return a single backend matching the specified filtering.
Note: this method is being deprecated. Please use an IBM Q Experience v2
account, and::
provider = IBMQ.get_provider(...)
provider.get_backend('name')
instead.
Args:
name (str): name of the backend.
**kwargs (dict): dict used for filtering.
Returns:
BaseBackend: a backend matching the filtering.
Raises:
QiskitBackendNotFoundError: if no backend could be found or
more than one backend matches the filtering criteria.
"""
warnings.warn(
'IBMQ.get_backend() is being deprecated. '
'Please use IBMQ.get_provider() to retrieve a provider '
'and AccountProvider.get_backend("name") to retrieve a '
'backend.', DeprecationWarning)
# Don't issue duplicate warnings
with warnings.catch_warnings():
warnings.filterwarnings('ignore', category=DeprecationWarning)
backends = self.backends(name, **kwargs)
if len(backends) > 1:
raise QiskitBackendNotFoundError(
'More than one backend matches the criteria')
if not backends:
raise QiskitBackendNotFoundError('No backend matches the criteria')
return backends[0]
def get_backend(self, name=None, **kwargs):
backend = self._backends[0]
if name:
# pylint: disable=no-member
filtered_backends = [
backend for backend in self._backends if backend.name() == name
]
# pylint: enable=no-member
if not filtered_backends:
raise QiskitBackendNotFoundError()
else:
backend = filtered_backends[0]
return backend
def get_backend(self, name=None, **kwargs):
backends = self._backends.values()
# Special handling of the `name` parameter, to support alias resolution
# and deprecated names.
if name:
try:
resolved_name = resolve_backend_name(
name, backends, self._deprecated_backend_names(), {})
name = resolved_name
except LookupError as ex:
raise QiskitBackendNotFoundError(
f"The '{name}' backend is not installed in your system."
) from ex
return super().get_backend(name=name, **kwargs)