Remove provider-specific fake backends,FakeProvider class and relat…

…ed tools in 1.0 (#11376)

* Remove provider-specific fake backends, fake provider and related tools

* Add release note

* Remove sneaky fake generic

* Fix lint

* Fix typo, manifest and attempt to fix visual tests

* Fix seed in visual tests, change imports

* Remove deleted files and remove FakeBackend mentions from examples in API docs

* I'm sorry I'm at the point where I confuse 1s and 5s.

* Fix skip message when aer isn't installed

* Skip fake backend test with aer on windows

* Revert windows skip and limit v2 backend size

The underlying cause of the windows failures were actually much larger
performance issues in aer's `NoiseModel.from_backend()` constructor
method when run with a BackendV2 instance. This is causing the
`NoiseModel` construction for `GenericBackendV2` to take a great deal of
time and use up all the memory we have available in the windows VMs in
CI. To avoid this issue in the short term until a fix can be added to
aer this commit just limits the size of the backend v2 examples we run
to prevent resources problems in CI.

* Avoid all to all connectivity in fake backend tests

The aer noise model construction was an artifact of using all to all
connectivity in the test. Using a more sparse connectivity alleviates
the performance issues. This commit switches to use a ring graph and
restores the larger qubit count backends.

---------

Co-authored-by: Matthew Treinish <[email protected]>

MANIFEST.in

@@ -3,7 +3,6 @@ include requirements.txt
 recursive-include qiskit/qasm/libs *.inc
 include qiskit/VERSION.txt
 include qiskit/visualization/circuit/styles/*.json
-recursive-include qiskit/providers/fake_provider/backends *.json
 recursive-include qiskit/providers/fake_provider/backends_v1 *.json
 
 # Include the tests files.

qiskit/providers/fake_provider/__init__.py

@@ -20,29 +20,23 @@
 Overview
 ========
 
-The fake provider module contains fake providers, fake backends and other simulated backend
-implementations. The fake backends are built to mimic the behaviors of IBM Quantum systems
-using system snapshots. The system snapshots contain important information about the quantum
-system such as coupling map, basis gates, qubit properties (T1, T2, error rate, etc.) which
-are useful for testing the transpiler and performing
-noisy simulation of the system.
+The fake provider module in Qiskit contains fake (simulated) backend classes
+useful for testing the transpiler and other backend-facing functionality.
 
 Example Usage
 =============
 
-Here is an example of using a fake backend for transpilation and simulation.
+Here is an example of using a simulated backend for transpilation and running.
 
 .. plot::
    :include-source:
 
-   from qiskit import QuantumCircuit
-   from qiskit.providers.fake_provider import FakeManilaV2
-   from qiskit import transpile
+   from qiskit import QuantumCircuit, transpile
+   from qiskit.providers.fake_provider import GenericBackendV2
    from qiskit.visualization import plot_histogram
 
-
-   # Get a fake backend from the fake provider
-   backend = FakeManilaV2()
+   # Generate a 5-qubit simulated backend
+   backend = GenericBackendV2(num_qubits=5)
 
    # Create a simple circuit
    circuit = QuantumCircuit(3)
@@ -56,201 +50,56 @@
    transpiled_circuit = transpile(circuit, backend)
    transpiled_circuit.draw('mpl')
 
-   # Run the transpiled circuit using the simulated fake backend
+   # Run the transpiled circuit using the simulated backend
    job = backend.run(transpiled_circuit)
    counts = job.result().get_counts()
    plot_histogram(counts)
 
-.. important::
-
-    Please note that the simulation is done using a noise model generated from system snapshots
-    obtained in the past (sometimes a few years ago) and the results are not representative of the
-    latest behaviours of the real quantum system which the fake backend is mimicking. If you want to
-    run noisy simulations to compare with the real quantum system you will need to create a noise
-    model from the current properties of the backend manually.
-
-Fake Providers
-==============
-
-Fake providers provide access to a list of fake backends.
-
-.. autosummary::
-    :toctree: ../stubs/
-
-    FakeProviderForBackendV2
-    FakeProvider
-
-Fake Backends
-=============
-
-Fake V2 Backends
-----------------
-
-Fake V2 backends are fake backends with IBM Quantum systems snapshots implemented with
-:mod:`~qiskit.providers.backend.BackendV2` interface.  They are all subclasses of
-:class:`FakeBackendV2`.
-
-.. autosummary::
-    :toctree: ../stubs/
-
-    FakeAlmadenV2
-    FakeArmonkV2
-    FakeAthensV2
-    FakeAuckland
-    FakeBelemV2
-    FakeBoeblingenV2
-    FakeBogotaV2
-    FakeBrooklynV2
-    FakeBurlingtonV2
-    FakeCairoV2
-    FakeCambridgeV2
-    FakeCasablancaV2
-    FakeEssexV2
-    FakeGeneva
-    FakeGuadalupeV2
-    FakeHanoiV2
-    FakeJakartaV2
-    FakeJohannesburgV2
-    FakeKolkataV2
-    FakeLagosV2
-    FakeLimaV2
-    FakeLondonV2
-    FakeManhattanV2
-    FakeManilaV2
-    FakeMelbourneV2
-    FakeMontrealV2
-    FakeMumbaiV2
-    FakeNairobiV2
-    FakeOslo
-    FakeOurenseV2
-    FakeParisV2
-    FakePerth
-    FakePrague
-    FakePoughkeepsieV2
-    FakeQuitoV2
-    FakeRochesterV2
-    FakeRomeV2
-    .. FakeRueschlikonV2 # no v2 version
-    FakeSantiagoV2
-    FakeSherbrooke
-    FakeSingaporeV2
-    FakeSydneyV2
-    .. FakeTenerifeV2 # no v2 version
-    .. FakeTokyoV2 # no v2 version
-    FakeTorontoV2
-    FakeValenciaV2
-    FakeVigoV2
-    FakeWashingtonV2
-    FakeYorktownV2
-
-Fake V1 Backends
-----------------
 
-Fake V1 backends are fake backends with IBM Quantum systems snapshots implemented with
-:mod:`~qiskit.providers.backend.BackendV1` interface.
+V2 Simulated Backends
+=====================
 
 .. autosummary::
     :toctree: ../stubs/
 
-    FakeAlmaden
-    FakeArmonk
-    FakeAthens
-    FakeBelem
-    FakeBoeblingen
-    FakeBogota
-    FakeBrooklyn
-    FakeBurlington
-    FakeCairo
-    FakeCambridge
-    FakeCasablanca
-    FakeEssex
-    FakeGuadalupe
-    FakeHanoi
-    FakeJakarta
-    FakeJohannesburg
-    FakeKolkata
-    FakeLagos
-    FakeLima
-    FakeLondon
-    FakeManhattan
-    FakeManila
-    FakeMelbourne
-    FakeMontreal
-    FakeMumbai
-    FakeNairobi
-    FakeOurense
-    FakeParis
-    FakePoughkeepsie
-    FakeQuito
-    FakeRochester
-    FakeRome
-    FakeRueschlikon
-    FakeSantiago
-    FakeSingapore
-    FakeSydney
-    FakeTenerife
-    FakeTokyo
-    FakeToronto
-    FakeValencia
-    FakeVigo
-    FakeWashington
-    FakeYorktown
-
-Special Fake Backends
-=====================
+    GenericBackendV2
 
-Special fake backends are fake backends that were created for special testing purposes.
+V1 Fake Backends (Legacy interface)
+===================================
 
 .. autosummary::
     :toctree: ../stubs/
 
-    FakeQasmSimulator
     FakeOpenPulse2Q
     FakeOpenPulse3Q
     Fake1Q
-    FakeBackendV2
-    FakeBackend5QV2
-    FakeMumbaiFractionalCX
-    GenericBackendV2
+    Fake5QV1
+    Fake20QV1
+    Fake7QPulseV1
+    Fake27QPulseV1
+    Fake127QPulseV1
 
 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
+The V1 fake backends are based on a set of base classes:
 
 .. 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
 
-# Fake providers
-from .fake_provider import FakeProviderFactory, FakeProviderForBackendV2, FakeProvider
-
-# Standard fake backends with IBM Quantum systems snapshots
-from .backends import *
-
 # Special fake backends for special testing purposes
-from .fake_qasm_simulator import FakeQasmSimulator
 from .fake_openpulse_2q import FakeOpenPulse2Q
 from .fake_openpulse_3q import FakeOpenPulse3Q
 from .fake_1q import Fake1Q
-from .fake_backend_v2 import FakeBackendV2, FakeBackend5QV2
-from .fake_mumbai_v2 import FakeMumbaiFractionalCX
 
 # Generic fake backends
-from .backends_v1 import *
+from .backends_v1 import Fake5QV1, Fake20QV1, Fake7QPulseV1, Fake27QPulseV1, Fake127QPulseV1
 from .generic_backend_v2 import GenericBackendV2