Fix broken documentation references in qiskit.providers

qiskit/providers/__init__.py

@@ -64,9 +64,9 @@
 deprecation is to give providers enough time to do their own deprecation of a
 potential end user impacting change in a user facing part of the interface
 prior to bumping their version. For example, let's say we changed the signature
-to ``Backend.run()`` in ``BackendV34`` in a backwards incompatible way, before
-Aer could update its :class:`~qiskit.providers.aer.aerbackend.AerBackend` class
-to use version 34 they'd need to deprecate the old signature prior to switching
+to ``Backend.run()`` in ``BackendV34`` in a backwards incompatible way. Before
+Aer could update its :class:`~qiskit_aer.AerSimulator` class
+to be based on version 34 they'd need to deprecate the old signature prior to switching
 over. The changeover for Aer is not guaranteed to be lockstep with Terra so we
 need to ensure there is a sufficient amount of time for Aer to complete its
 deprecation cycle prior to removing version 33 (ie making version 34
@@ -734,13 +734,13 @@ def status(self):
      -
    * - ``backend.properties().readout_error(0)``
      - ``backend.target["measure"][(0,)].error``
-     - In :obj:`~BackendV2` the error rate for the :class:`~qiskit.circuit.Measure`
+     - In :obj:`~BackendV2` the error rate for the :class:`~qiskit.circuit.library.Measure`
        operation on a given qubit is used to model the readout error. However a
        :obj:`~BackendV2` can implement multiple measurement types and list them
        separately in a :class:`~qiskit.transpiler.Target`.
    * - ``backend.properties().readout_length(0)``
      - ``backend.target["measure"][(0,)].duration``
-     - In :obj:`~BackendV2` the duration for the :class:`~qiskit.circuit.Measure`
+     - In :obj:`~BackendV2` the duration for the :class:`~qiskit.circuit.library.Measure`
        operation on a given qubit is used to model the readout length. However, a
        :obj:`~BackendV2` can implement multiple measurement types and list them
        separately in a :class:`~qiskit.transpiler.Target`.

qiskit/providers/backend.py

@@ -62,6 +62,11 @@ class BackendV1(Backend, ABC):
     ease the transition for users and provider maintainers to the new versioned providers.
     Expect, future versions of this abstract class to change the data model and
     interface.
+
+    Subclasses of this should override the public method :meth:`run` and the internal
+    :meth:`_default_options`:
+
+    .. automethod:: _default_options
     """
 
     version = 1
@@ -113,7 +118,6 @@ def _default_options(cls):
             qiskit.providers.Options: A options object with
                 default values set
         """
-        pass
 
     def set_options(self, **fields):
         """Set the options fields for the backend
@@ -217,7 +221,7 @@ class can handle either situation.
 
         Args:
             run_input (QuantumCircuit or Schedule or list): An individual or a
-                list of :class:`~qiskit.circuits.QuantumCircuit` or
+                list of :class:`~qiskit.circuit.QuantumCircuit` or
                 :class:`~qiskit.pulse.Schedule` objects to run on the backend.
                 For legacy providers migrating to the new versioned providers,
                 provider interface a :class:`~qiskit.qobj.QasmQobj` or
@@ -251,7 +255,7 @@ class QubitProperties:
     __slots__ = ("t1", "t2", "frequency")
 
     def __init__(self, t1=None, t2=None, frequency=None):
-        """Create a new ``QubitProperties`` object
+        """Create a new :class:`QubitProperties` object.
 
         Args:
             t1: The T1 time for a qubit in seconds
@@ -282,8 +286,8 @@ class BackendV2(Backend, ABC):
     something like a ``shots`` field for a backend that runs experiments which
     would contain an int for how many shots to execute.
 
-    If migrating a provider from :class:`~qiskit.providers.BackendV1` or
-    :class:`~qiskit.providers.BaseBackend` one thing to keep in mind is for
+    If migrating a provider from :class:`~qiskit.providers.BackendV1`
+    one thing to keep in mind is for
     backwards compatibility you might need to add a configuration method that
     will build a :class:`~qiskit.providers.models.BackendConfiguration` object
     and :class:`~qiskit.providers.models.BackendProperties` from the attributes
@@ -308,6 +312,11 @@ class BackendV2(Backend, ABC):
     that contains the custom compilation passes and then for the hook methods on
     the backend object to return the plugin name so that :func:`~.transpile` will
     use it by default when targetting the backend.
+
+    Subclasses of this should override the public method :meth:`run` and the internal
+    :meth:`_default_options`:
+
+    .. automethod:: _default_options
     """
 
     version = 2
@@ -352,9 +361,15 @@ def __init__(
                     raise AttributeError("Options field %s is not valid for this backend" % field)
             self._options.update_config(**fields)
         self.name = name
+        """Name of the backend."""
         self.description = description
+        """Optional human-readable description."""
         self.online_date = online_date
+        """Date that the backend came online."""
         self.backend_version = backend_version
+        """Version of the backend being provided.  This is not the same as
+        :attr:`.BackendV2.version`, which is the version of the :class:`~.providers.Backend`
+        abstract interface."""
         self._coupling_map = None
 
     @property
@@ -432,8 +447,8 @@ def dt(self) -> Union[float, None]:
         scheduling.
 
         Returns:
-            dt: The input signal timestep in seconds. If the backend doesn't
-            define ``dt`` ``None`` will be returned
+            The input signal timestep in seconds. If the backend doesn't define ``dt``, ``None`` will
+            be returned.
         """
         return self.target.dt
 
@@ -442,7 +457,7 @@ def dtm(self) -> float:
         """Return the system time resolution of output signals
 
         Returns:
-            dtm: The output signal timestep in seconds.
+            The output signal timestep in seconds.
 
         Raises:
             NotImplementedError: if the backend doesn't support querying the
@@ -458,7 +473,7 @@ def meas_map(self) -> List[List[int]]:
         scheduling.
 
         Returns:
-            meas_map: The grouping of measurements which are multiplexed
+            The grouping of measurements which are multiplexed
 
         Raises:
             NotImplementedError: if the backend doesn't support querying the
@@ -482,12 +497,12 @@ def qubit_properties(
 
         Args:
             qubit: The qubit to get the
-                :class:`~qiskit.provider.QubitProperties` object for. This can
+                :class:`.QubitProperties` object for. This can
                 be a single integer for 1 qubit or a list of qubits and a list
-                of :class:`~qiskit.provider.QubitProperties` objects will be
+                of :class:`.QubitProperties` objects will be
                 returned in the same order
         Returns:
-            qubit_properties: The :class:`~.QubitProperties` object for the
+            The :class:`~.QubitProperties` object for the
             specified qubit. If a list of qubits is provided a list will be
             returned. If properties are missing for a qubit this can be
             ``None``.
@@ -623,15 +638,15 @@ class can handle either situation.
 
         Args:
             run_input (QuantumCircuit or Schedule or ScheduleBlock or list): An
-                individual or a list of
-                :class:`~qiskit.circuits.QuantumCircuit,
-                :class:`~qiskit.pulse.ScheduleBlock`, or
-                :class:`~qiskit.pulse.Schedule` objects to run on the backend.
+                individual or a list of :class:`.QuantumCircuit`,
+                :class:`~qiskit.pulse.ScheduleBlock`, or :class:`~qiskit.pulse.Schedule` objects to
+                run on the backend.
             options: Any kwarg options to pass to the backend for running the
                 config. If a key is also present in the options
                 attribute/object then the expectation is that the value
                 specified will be used instead of what's set in the options
                 object.
+
         Returns:
             Job: The job object for the run
         """

qiskit/providers/basicaer/basicaerjob.py

@@ -40,7 +40,7 @@ def result(self, timeout=None):
         """Get job result .
 
         Returns:
-            qiskit.Result: Result object
+            qiskit.result.Result: Result object
         """
         if timeout is not None:
             warnings.warn(

qiskit/providers/basicaer/qasm_simulator.py

@@ -336,7 +336,7 @@ def _validate_measure_sampling(self, experiment):
         """Determine if measure sampling is allowed for an experiment
 
         Args:
-            experiment (QobjExperiment): a qobj experiment.
+            experiment (QasmQobjExperiment): a qobj experiment.
         """
         # If shots=1 we should disable measure sampling.
         # This is also required for statevector simulator to return the
@@ -461,7 +461,7 @@ def run_experiment(self, experiment):
         """Run an experiment (circuit) and return a single experiment result.
 
         Args:
-            experiment (QobjExperiment): experiment from qobj experiments list
+            experiment (QasmQobjExperiment): experiment from qobj experiments list
 
         Returns:
              dict: A result dictionary which looks something like::

qiskit/providers/basicaer/unitary_simulator.py

@@ -292,7 +292,7 @@ def run_experiment(self, experiment):
         """Run an experiment (circuit) and return a single experiment result.
 
         Args:
-            experiment (QobjExperiment): experiment from qobj experiments list
+            experiment (QasmQobjExperiment): experiment from qobj experiments list
 
         Returns:
             dict: A result dictionary which looks something like::
@@ -312,8 +312,8 @@ def run_experiment(self, experiment):
                 }
 
         Raises:
-            BasicAerError: if the number of qubits in the circuit is greater than 24.
-            Note that the practical qubit limit is much lower than 24.
+            BasicAerError: if the number of qubits in the circuit is greater than 24.  Note that the
+                practical qubit limit is much lower than 24.
         """
         start = time.time()
         self._number_of_qubits = experiment.header.n_qubits

qiskit/providers/fake_provider/__init__.py

@@ -99,7 +99,8 @@
 ----------------
 
 Fake V2 backends are fake backends with IBM Quantum systems snapshots implemented with
-:mod:`~qiskit.providers.backend.BackendV2` interface.
+:mod:`~qiskit.providers.backend.BackendV2` interface.  They are all subclasses of
+:class:`FakeBackendV2`.
 
 .. autosummary::
     :toctree: ../stubs/
@@ -224,13 +225,26 @@
     FakeMumbaiFractionalCX
     ConfigurableFakeBackend
 
+Fake Backend Base Classes
+=========================
+
+The fake backends based on IBM hardware are based on a set of base classes:
+
+.. currentmodule:: qiskit.providers.fake_provider.fake_backend
+.. autoclass:: qiskit.providers.fake_provider.fake_backend.FakeBackendV2
+
+.. currentmodule:: qiskit.providers.fake_provider
+.. autoclass:: FakeBackend
+.. autoclass:: FakeQasmBackend
+.. autoclass:: FakePulseBackend
 """
 
 # Fake job and qobj classes
 from .fake_job import FakeJob
 from .fake_qobj import FakeQobj
 
 # Base classes for fake backends
+from . import fake_backend
 from .fake_backend import FakeBackend
 from .fake_qasm_backend import FakeQasmBackend
 from .fake_pulse_backend import FakePulseBackend

qiskit/providers/fake_provider/fake_backend.py

@@ -211,7 +211,7 @@ def dtm(self) -> float:
         """Return the system time resolution of output signals
 
         Returns:
-            dtm: The output signal timestep in seconds.
+            The output signal timestep in seconds.
         """
         dtm = self._conf_dict.get("dtm")
         if dtm is not None:
@@ -227,7 +227,7 @@ def meas_map(self) -> List[List[int]]:
         scheduling.
 
         Returns:
-            meas_map: The grouping of measurements which are multiplexed
+            The grouping of measurements which are multiplexed
         """
         return self._conf_dict.get("meas_map")
 
@@ -316,19 +316,20 @@ def run(self, run_input, **options):
         Args:
             run_input (QuantumCircuit or Schedule or ScheduleBlock or list): An
                 individual or a list of
-                :class:`~qiskit.circuits.QuantumCircuit,
+                :class:`~qiskit.circuit.QuantumCircuit`,
                 :class:`~qiskit.pulse.ScheduleBlock`, or
                 :class:`~qiskit.pulse.Schedule` objects to run on the backend.
             options: Any kwarg options to pass to the backend for running the
                 config. If a key is also present in the options
                 attribute/object then the expectation is that the value
                 specified will be used instead of what's set in the options
                 object.
+
         Returns:
             Job: The job object for the run
+
         Raises:
-            QiskitError: If a pulse job is supplied and qiskit-aer is not
-            installed.
+            QiskitError: If a pulse job is supplied and qiskit-aer is not installed.
         """
         circuits = run_input
         pulse_job = None

qiskit/providers/models/__init__.py

@@ -35,6 +35,8 @@
    PulseDefaults
    Command
    JobStatus
+   GateProperties
+   Nduv
 """
 
 from .backendconfiguration import (
@@ -44,7 +46,7 @@
     UchannelLO,
     GateConfig,
 )
-from .backendproperties import BackendProperties
+from .backendproperties import BackendProperties, GateProperties, Nduv
 from .backendstatus import BackendStatus
 from .jobstatus import JobStatus
 from .pulsedefaults import PulseDefaults, Command

qiskit/providers/models/backendconfiguration.py

@@ -285,7 +285,7 @@ def __init__(
                 backend is a simulator
             credits_required (bool): True if backend requires credits to run a
                 job.
-            online_date (datetime): The date that the device went online
+            online_date (datetime.datetime): The date that the device went online
             display_name (str): Alternate name field for the backend
             description (str): A description for the backend
             tags (list): A list of string tags to describe the backend
@@ -593,7 +593,7 @@ def __init__(
                 backend is a simulator
             credits_required (bool): True if backend requires credits to run a
                 job.
-            online_date (datetime): The date that the device went online
+            online_date (datetime.datetime): The date that the device went online
             display_name (str): Alternate name field for the backend
             description (str): A description for the backend
             tags (list): A list of string tags to describe the backend