BackendV1
class qiskit.providers.BackendV1(configuration, provider=None, **fields)
Abstract class for Backends
This abstract class is to be used for all Backend objects created by a provider. There are several classes of information contained in a Backend. The first are the attributes of the class itself. These should be used to defined the immutable characteristics of the backend. The options attribute of the backend is used to contain the dynamic user configurable options of the backend. It should be used more for runtime options that configure how the backend is used. For example, something like a shots field for a backend that runs experiments which would contain an int for how many shots to execute. The properties attribute is optionally defined BackendProperties object and is used to return measured properties, or properties of a backend that may change over time. The simplest example of this would be a version string, which will change as a backend is updated, but also could be something like noise parameters for backends that run experiments.
This first version of the Backend abstract class is written to be mostly backwards compatible with the legacy providers interface. This includes reusing the model objects BackendProperties and BackendConfiguration. This was done to 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 run() and the internal _default_options():
_default_options
abstract classmethod _default_options()
Return the default options
This method will return a qiskit.providers.Options subclass object that will be used for the default options. These should be the default parameters to use for the options of the backend.
Returns
A options object with
default values set
Return type
Initialize a backend class
Parameters
- configuration (BackendConfiguration) – A backend configuration object for the backend object.
- provider (qiskit.providers.Provider) – Optionally, the provider object that this Backend comes from.
- fields – kwargs for the values to use to override the default options.
Raises
AttributeError – if input field not a valid options
Attributes
options
Return the options for the backend
The options of a backend are the dynamic parameters defining how the backend is used. These are used to control the run() method.
version
Default value: 1
Methods
configuration
configuration()
Return the backend configuration.
Returns
the configuration for the backend.
Return type
name
properties
properties()
Return the backend properties.
Returns
the configuration for the backend. If the backend does not support properties, it returns None.
Return type
provider
provider()
Return the backend Provider.
Returns
the Provider responsible for the backend.
Return type
run
abstract run(run_input, **options)
Run on the backend.
This method returns a Job object that runs circuits. Depending on the backend this may be either an async or sync call. It is at the discretion of the provider to decide whether running should block until the execution is finished or not: the Job class can handle either situation.
Parameters
- run_input (QuantumCircuit orSchedule orlist) – An individual or a list of
QuantumCircuitorScheduleobjects to run on the backend. For legacy providers migrating to the new versioned providers, provider interface aQasmQobjorPulseQobjobjects should probably be supported too (but deprecated) for backwards compatibility. Be sure to update the docstrings of subclasses implementing this method to document that. New provider implementations should not do this though asqiskit.qobjwill be deprecated and removed along with the legacy providers interface. - 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
The job object for the run
Return type
set_options
set_options(**fields)
Set the options fields for the backend
This method is used to update the options of a backend. If you need to change any of the options prior to running just pass in the kwarg with the new value for the options.
Parameters
fields – The fields to update the options
Raises
AttributeError – If the field passed in is not part of the options