BasicSimulator uses deprecated BackendConfiguration

[1ucian0]

While deprecating the models in qiskit.providers.models I realized that BasicSimulator uses BackendConfiguration, which is one of those models.

[ElePT]

When migrating BasicSimulator to BackendV2 we decided to keep the configuration attribute for backward-ish compatibility with the interface of BasicAer (BackendV1), but it's not a required attribute for BackendV2. I think that now that BackendConfiguration is deprecated we can simply deprecate BasicSimulator.configuration.

[csi21]

Hello @ElePT, What would be the equivalent of the deprecated BackendConfiguarion.from_dict() in Qiskit 2.0? Is there a method to initiate a configuration from a dictionary, as in Qiskit 1.2?

[ElePT]

Hi @csi21, what's deprecated is the BackendConfiguration class as a whole. The alternative to communicate backend constraints is using a Target. As a transition step, you can build a Target from the configuration values using the following method:

Target.from_configuration(
         basis_gates, 
         num_qubits=None, 
         coupling_map=None, 
         inst_map=None, 
         backend_properties=None, 
         instruction_durations=None, 
         concurrent_measurements=None, 
         dt=None, 
         timing_constraints=None, 
         custom_name_mapping=None)