347 lines
14 KiB
Plaintext
347 lines
14 KiB
Plaintext
---
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title: BackendV2
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description: API reference for qiskit.providers.BackendV2
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in_page_toc_min_heading_level: 1
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python_api_type: class
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python_api_name: qiskit.providers.BackendV2
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---
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# BackendV2
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<Class id="qiskit.providers.BackendV2" isDedicatedPage={true} github="https://github.com/qiskit/qiskit/tree/stable/0.23/qiskit/providers/backend.py" signature="BackendV2(provider=None, name=None, description=None, online_date=None, backend_version=None, **fields)" modifiers="class">
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Bases: [`qiskit.providers.backend.Backend`](qiskit.providers.Backend "qiskit.providers.backend.Backend"), `abc.ABC`
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Abstract class for Backends
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This abstract class is to be used for all Backend objects created by a provider. This version differs from earlier abstract Backend classes in that the configuration attribute no longer exists. Instead, attributes exposing equivalent required immutable properties of the backend device are added. For example `backend.configuration().n_qubits` is accessible from `backend.num_qubits` now.
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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.
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If migrating a provider from [`BackendV1`](qiskit.providers.BackendV1 "qiskit.providers.BackendV1") or `BaseBackend` one thing to keep in mind is for backwards compatibility you might need to add a configuration method that will build a [`BackendConfiguration`](qiskit.providers.models.BackendConfiguration "qiskit.providers.models.BackendConfiguration") object and [`BackendProperties`](qiskit.providers.models.BackendProperties "qiskit.providers.models.BackendProperties") from the attributes defined in this class for backwards compatibility.
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A backend object can optionally contain methods named `get_translation_stage_plugin` and `get_scheduling_stage_plugin`. If these methods are present on a backend object and this object is used for [`transpile()`](qiskit.compiler.transpile "qiskit.compiler.transpile") or [`generate_preset_pass_manager()`](qiskit.transpiler.preset_passmanagers.generate_preset_pass_manager "qiskit.transpiler.preset_passmanagers.generate_preset_pass_manager") the transpilation process will default to using the output from those methods as the scheduling stage and the translation compilation stage. This enables a backend which has custom requirements for compilation to specify a stage plugin for these stages to enable custom transformation of the circuit to ensure it is runnable on the backend. These hooks are enabled by default and should only be used to enable extra compilation steps if they are **required** to ensure a circuit is executable on the backend or have the expected level of performance. These methods are passed no input arguments and are expected to return a `str` representing the method name which should be a stage plugin (see: [`qiskit.transpiler.preset_passmanagers.plugin`](transpiler_plugins#module-qiskit.transpiler.preset_passmanagers.plugin "qiskit.transpiler.preset_passmanagers.plugin") for more details on plugins). The typical expected use case is for a backend provider to implement a stage plugin for `translation` or `scheduling` that contains the custom compilation passes and then for the hook methods on the backend object to return the plugin name so that [`transpile()`](qiskit.compiler.transpile "qiskit.compiler.transpile") will use it by default when targetting the backend.
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Initialize a BackendV2 based backend
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**Parameters**
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* **provider** (`Optional`\[[`Provider`](qiskit.providers.Provider "qiskit.providers.provider.Provider")]) – An optional backwards reference to the [`Provider`](qiskit.providers.Provider "qiskit.providers.Provider") object that the backend is from
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* **name** (`Optional`\[`str`]) – An optional name for the backend
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* **description** (`Optional`\[`str`]) – An optional description of the backend
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* **online\_date** (`Optional`\[`datetime`]) – An optional datetime the backend was brought online
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* **backend\_version** (`Optional`\[`str`]) – An optional backend version string. This differs from the [`version`](#qiskit.providers.BackendV2.version "qiskit.providers.BackendV2.version") attribute as [`version`](#qiskit.providers.BackendV2.version "qiskit.providers.BackendV2.version") is for the abstract [`Backend`](qiskit.providers.Backend "qiskit.providers.Backend") abstract interface version of the object while `backend_version` is for versioning the backend itself.
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* **fields** – kwargs for the values to use to override the default options.
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**Raises**
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**AttributeError** – If a field is specified that’s outside the backend’s options
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## Methods
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### acquire\_channel
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<Function id="qiskit.providers.BackendV2.acquire_channel" signature="BackendV2.acquire_channel(qubit)">
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Return the acquisition channel for the given qubit.
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This is required to be implemented if the backend supports Pulse scheduling.
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**Returns**
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The Qubit measurement acquisition line.
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**Return type**
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[AcquireChannel](qiskit.pulse.channels.AcquireChannel "qiskit.pulse.channels.AcquireChannel")
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**Raises**
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**NotImplementedError** – if the backend doesn’t support querying the measurement mapping
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</Function>
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### control\_channel
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<Function id="qiskit.providers.BackendV2.control_channel" signature="BackendV2.control_channel(qubits)">
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Return the secondary drive channel for the given qubit
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This is typically utilized for controlling multiqubit interactions. This channel is derived from other channels.
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This is required to be implemented if the backend supports Pulse scheduling.
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**Parameters**
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**qubits** (`Iterable`\[`int`]) – Tuple or list of qubits of the form `(control_qubit, target_qubit)`.
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**Returns**
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The multi qubit control line.
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**Return type**
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List\[[ControlChannel](qiskit.pulse.channels.ControlChannel "qiskit.pulse.channels.ControlChannel")]
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**Raises**
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**NotImplementedError** – if the backend doesn’t support querying the measurement mapping
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</Function>
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### drive\_channel
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<Function id="qiskit.providers.BackendV2.drive_channel" signature="BackendV2.drive_channel(qubit)">
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Return the drive channel for the given qubit.
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This is required to be implemented if the backend supports Pulse scheduling.
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**Returns**
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The Qubit drive channel
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**Return type**
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[DriveChannel](qiskit.pulse.channels.DriveChannel "qiskit.pulse.channels.DriveChannel")
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**Raises**
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**NotImplementedError** – if the backend doesn’t support querying the measurement mapping
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</Function>
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### measure\_channel
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<Function id="qiskit.providers.BackendV2.measure_channel" signature="BackendV2.measure_channel(qubit)">
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Return the measure stimulus channel for the given qubit.
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This is required to be implemented if the backend supports Pulse scheduling.
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**Returns**
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The Qubit measurement stimulus line
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**Return type**
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[MeasureChannel](qiskit.pulse.channels.MeasureChannel "qiskit.pulse.channels.MeasureChannel")
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**Raises**
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**NotImplementedError** – if the backend doesn’t support querying the measurement mapping
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</Function>
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### qubit\_properties
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<Function id="qiskit.providers.BackendV2.qubit_properties" signature="BackendV2.qubit_properties(qubit)">
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Return QubitProperties for a given qubit.
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If there are no defined or the backend doesn’t support querying these details this method does not need to be implemented.
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**Parameters**
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**qubit** (`Union`\[`int`, `List`\[`int`]]) – The qubit to get the `QubitProperties` object for. This can be a single integer for 1 qubit or a list of qubits and a list of `QubitProperties` objects will be returned in the same order
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**Returns**
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The [`QubitProperties`](qiskit.providers.QubitProperties "qiskit.providers.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`.
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**Return type**
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qubit\_properties
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**Raises**
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**NotImplementedError** – if the backend doesn’t support querying the qubit properties
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</Function>
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### run
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<Function id="qiskit.providers.BackendV2.run" signature="BackendV2.run(run_input, **options)" modifiers="abstract">
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Run on the backend.
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This method returns a [`Job`](qiskit.providers.Job "qiskit.providers.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.
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**Parameters**
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* **run\_input** ([*QuantumCircuit*](qiskit.circuit.QuantumCircuit "qiskit.circuit.QuantumCircuit") *or*[*Schedule*](qiskit.pulse.Schedule "qiskit.pulse.Schedule") *or*[*ScheduleBlock*](qiskit.pulse.ScheduleBlock "qiskit.pulse.ScheduleBlock") *or list*) – An individual or a list of `ScheduleBlock`, or [`Schedule`](qiskit.pulse.Schedule "qiskit.pulse.Schedule") objects to run on the backend.
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* **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.
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**Returns**
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The job object for the run
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**Return type**
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[Job](qiskit.providers.Job "qiskit.providers.Job")
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</Function>
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### set\_options
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<Function id="qiskit.providers.BackendV2.set_options" signature="BackendV2.set_options(**fields)">
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Set the options fields for the backend
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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.
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**Parameters**
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**fields** – The fields to update the options
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**Raises**
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**AttributeError** – If the field passed in is not part of the options
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</Function>
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## Attributes
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### coupling\_map
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<Attribute id="qiskit.providers.BackendV2.coupling_map">
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Return the [`CouplingMap`](qiskit.transpiler.CouplingMap "qiskit.transpiler.CouplingMap") object
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</Attribute>
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### dt
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<Attribute id="qiskit.providers.BackendV2.dt">
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Return the system time resolution of input signals
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This is required to be implemented if the backend supports Pulse scheduling.
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**Returns**
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The input signal timestep in seconds. If the backend doesn’t define `dt` `None` will be returned
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**Return type**
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dt
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</Attribute>
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### dtm
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<Attribute id="qiskit.providers.BackendV2.dtm">
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Return the system time resolution of output signals
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**Returns**
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The output signal timestep in seconds.
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**Return type**
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dtm
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**Raises**
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**NotImplementedError** – if the backend doesn’t support querying the output signal timestep
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</Attribute>
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### instruction\_durations
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<Attribute id="qiskit.providers.BackendV2.instruction_durations">
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Return the [`InstructionDurations`](qiskit.transpiler.InstructionDurations "qiskit.transpiler.InstructionDurations") object.
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</Attribute>
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### instruction\_schedule\_map
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<Attribute id="qiskit.providers.BackendV2.instruction_schedule_map">
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Return the [`InstructionScheduleMap`](qiskit.pulse.InstructionScheduleMap "qiskit.pulse.InstructionScheduleMap") for the instructions defined in this backend’s target.
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</Attribute>
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### instructions
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<Attribute id="qiskit.providers.BackendV2.instructions">
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A list of Instruction tuples on the backend of the form `(instruction, (qubits)`
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**Return type**
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`List`\[`Tuple`\[[`Instruction`](qiskit.circuit.Instruction "qiskit.circuit.instruction.Instruction"), `Tuple`\[`int`]]]
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</Attribute>
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### max\_circuits
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<Attribute id="qiskit.providers.BackendV2.max_circuits">
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The maximum number of circuits (or Pulse schedules) that can be run in a single job.
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If there is no limit this will return None
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</Attribute>
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### meas\_map
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<Attribute id="qiskit.providers.BackendV2.meas_map">
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Return the grouping of measurements which are multiplexed
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This is required to be implemented if the backend supports Pulse scheduling.
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**Returns**
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The grouping of measurements which are multiplexed
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**Return type**
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meas\_map
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**Raises**
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**NotImplementedError** – if the backend doesn’t support querying the measurement mapping
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</Attribute>
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### num\_qubits
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<Attribute id="qiskit.providers.BackendV2.num_qubits">
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Return the number of qubits the backend has.
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**Return type**
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`int`
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</Attribute>
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### operation\_names
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<Attribute id="qiskit.providers.BackendV2.operation_names">
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A list of instruction names that the backend supports.
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**Return type**
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`List`\[`str`]
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</Attribute>
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### operations
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<Attribute id="qiskit.providers.BackendV2.operations">
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A list of [`Instruction`](qiskit.circuit.Instruction "qiskit.circuit.Instruction") instances that the backend supports.
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**Return type**
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`List`\[[`Instruction`](qiskit.circuit.Instruction "qiskit.circuit.instruction.Instruction")]
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</Attribute>
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### options
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<Attribute id="qiskit.providers.BackendV2.options">
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Return the options for the backend
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The options of a backend are the dynamic parameters defining how the backend is used. These are used to control the [`run()`](qiskit.providers.BackendV2#run "qiskit.providers.BackendV2.run") method.
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</Attribute>
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### provider
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<Attribute id="qiskit.providers.BackendV2.provider">
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Return the backend Provider.
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**Returns**
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the Provider responsible for the backend.
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**Return type**
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[Provider](qiskit.providers.Provider "qiskit.providers.Provider")
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</Attribute>
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### target
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<Attribute id="qiskit.providers.BackendV2.target">
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A [`qiskit.transpiler.Target`](qiskit.transpiler.Target "qiskit.transpiler.Target") object for the backend.
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**Return type**
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[Target](qiskit.transpiler.Target "qiskit.transpiler.Target")
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</Attribute>
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### version
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<Attribute id="qiskit.providers.BackendV2.version" attributeValue="2" />
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</Class>
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