Fix name of AerSimulator generated by AerProvider

qiskit_aer/aerprovider.py

@@ -36,19 +36,22 @@ def _get_backends():
             devices = AerSimulator().available_devices()
             backends = []
             for method in methods:
-                name = "aer_simulator"
-                if method not in [None, "automatic"]:
-                    name += f"_{method}"
-                device_name = "CPU"
-                backends.append((name, AerSimulator, method, device_name))
-
-                # Add GPU device backends
-                if method in ["statevector", "density_matrix", "unitary"]:
-                    for device in devices:
-                        if device != "CPU":
-                            new_name = f"{name}_{device}".lower()
-                            device_name = device
-                            backends.append((new_name, AerSimulator, method, device_name))
+                for device in devices:
+                    name = "aer_simulator"
+                    if method in [None, "automatic"]:
+                        backends.append((name, AerSimulator, method, device))
+                    else:
+                        name += f"_{method}"
+                        if method == "tensor_network":
+                            if device == "GPU":
+                                name += f"_{device}".lower()
+                                backends.append((name, AerSimulator, method, device))
+                        else:
+                            if device == "CPU":
+                                backends.append((name, AerSimulator, method, device))
+                            elif method in ["statevector", "density_matrix", "unitary"]:
+                                name += f"_{device}".lower()
+                                backends.append((name, AerSimulator, method, device))
 
             # Add legacy backend names
             backends += [

qiskit_aer/backends/aer_simulator.py

@@ -716,6 +716,20 @@ def __init__(
         if configuration is None:
             configuration = QasmBackendConfiguration.from_dict(AerSimulator._DEFAULT_CONFIGURATION)
 
+        # set backend name from method and device in option
+        if "from" not in configuration.backend_name:
+            method = "automatic"
+            device = "CPU"
+            for key, value in backend_options.items():
+                if key == "method":
+                    method = value
+                if key == "device":
+                    device = value
+            if method not in [None, "automatic"]:
+                configuration.backend_name += f"_{method}"
+            if device not in [None, "CPU"]:
+                configuration.backend_name += f"_{device}".lower()
+
         # Cache basis gates since computing the intersection
         # of noise model, method, and config gates is expensive.
         self._cached_basis_gates = self._BASIS_GATES["automatic"]
@@ -806,17 +820,6 @@ def __repr__(self):
         pad = " " * (len(self.__class__.__name__) + 1)
         return f"{display[:-1]}\n{pad}noise_model={repr(noise_model)})"
 
-    def _name(self):
-        """Format backend name string for simulator"""
-        name = self._configuration.backend_name
-        method = getattr(self.options, "method", None)
-        if method not in [None, "automatic"]:
-            name += f"_{method}"
-        device = getattr(self.options, "device", None)
-        if device not in [None, "CPU"]:
-            name += f"_{device}".lower()
-        return name
-
     @classmethod
     def from_backend(cls, backend, **options):
         """Initialize simulator from backend."""
@@ -827,7 +830,7 @@ def from_backend(cls, backend, **options):
                 description = backend.description
 
             configuration = QasmBackendConfiguration(
-                backend_name=f"'aer_simulator({backend.name})",
+                backend_name=f"aer_simulator_from({backend.name})",
                 backend_version=backend.backend_version,
                 n_qubits=backend.num_qubits,
                 basis_gates=backend.operation_names,
@@ -851,7 +854,7 @@ def from_backend(cls, backend, **options):
 
             # Customize configuration name
             name = configuration.backend_name
-            configuration.backend_name = f"aer_simulator({name})"
+            configuration.backend_name = f"aer_simulator_from({name})"
 
             target = None
         else:
@@ -879,6 +882,8 @@ def available_methods(self):
 
     def available_devices(self):
         """Return the available simulation methods."""
+        if "_gpu" in self.name:
+            return ["GPU"]
         return copy.copy(self._AVAILABLE_DEVICES)
 
     def configuration(self):
@@ -896,8 +901,6 @@ def configuration(self):
             getattr(self.options, "method", "automatic")
         ]
         config.basis_gates = self._cached_basis_gates + config.custom_instructions
-        # Update simulator name
-        config.backend_name = self._name()
         return config
 
     def _execute_circuits(self, aer_circuits, noise_model, config):
@@ -931,6 +934,24 @@ def set_option(self, key, value):
         if key in ["method", "noise_model", "basis_gates"]:
             self._cached_basis_gates = self._basis_gates()
 
+        # update backend name
+        if key in ["method", "device"]:
+            if "from" not in self.name:
+                if key == "method":
+                    self.name = "aer_simulator"
+                    if value != "automatic":
+                        self.name += f"_{value}"
+                        device = getattr(self.options, "device", "CPU")
+                        if device != "CPU":
+                            self.name += f"_{device}".lower()
+                if key == "device":
+                    method = getattr(self.options, "method", "auto")
+                    self.name = "aer_simulator"
+                    if method != "automatic":
+                        self.name += f"_{method}"
+                        if value != "CPU":
+                            self.name += f"_{value}".lower()
+
     def _validate(self, qobj):
         """Semantic validations of the qobj which cannot be done via schemas.
 

releasenotes/notes/fix_aer_provider_backend-fef040819407bcca.yaml

@@ -0,0 +1,9 @@
+---
+fixes:
+  - |
+    Fixed backend name in backend.configuration when method and device is
+    specified from AerProvider, this issue is caused by upgrading
+    AerBackend to V2 backend.
+
+    Also fixed issue AerProvider did not enumerate tensor_network method
+    when GPU device is available

test/terra/backends/test_aer_provider.py

@@ -0,0 +1,63 @@
+# This code is part of Qiskit.
+#
+# (C) Copyright IBM 2018, 2021, 2024.
+#
+# This code is licensed under the Apache License, Version 2.0. You may
+# obtain a copy of this license in the LICENSE.txt file in the root directory
+# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
+#
+# Any modifications or derivative works of this code must retain this
+# copyright notice, and modified files need to carry a notice indicating
+# that they have been altered from the originals.
+"""
+Tests for AerProvider and AerSimulator
+"""
+
+from qiskit import *
+from qiskit.circuit.library import *
+from qiskit_aer import *
+
+from test.terra.common import QiskitAerTestCase
+
+
+class TestAerProvider(QiskitAerTestCase):
+    """Tests for AerProvider."""
+
+    def test_enum_backends(self):
+        """Test backends enumrated by AerProvider."""
+        provider = AerProvider()
+        for backend in provider.backends():
+            if "aer_simulator" in backend.name:
+                method = getattr(backend.options, "method", "automatic")
+                device = getattr(backend.options, "device", "CPU")
+                if method == "automatic":
+                    self.assertEqual(backend.name, "aer_simulator")
+                else:
+                    name = "aer_simulator"
+                    name += f"_{method}"
+                    if device != "CPU":
+                        name += f"_{device}".lower()
+                    self.assertEqual(backend.name, name)
+
+    def test_get_backend(self):
+        """Test running backend from AerProvider."""
+        provider = AerProvider()
+        backend = provider.get_backend("aer_simulator_density_matrix")
+        circuit = transpile(QuantumVolume(4, 10, seed=0), backend=backend, optimization_level=0)
+        circuit.measure_all()
+        results = backend.run(circuit, shots=100, seed_simulator=0).result()
+
+        self.assertEqual(results.results[0].metadata["method"], "density_matrix")
+        self.assertEqual(results.results[0].metadata["device"], "CPU")
+
+    def test_backend_name_by_set_option(self):
+        """Test backend name of AerSimulator by set_option."""
+        backend = AerSimulator()
+        if "GPU" in backend.available_devices():
+            backend.set_option("device", "GPU")
+            backend.set_option("method", "density_matrix")
+            self.assertEqual(backend.name, "aer_simulator_density_matrix_gpu")
+        else:
+            backend.set_option("device", "Thrust")
+            backend.set_option("method", "density_matrix")
+            self.assertEqual(backend.name, "aer_simulator_density_matrix_thrust")