Specify Sampler options

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Package versions

The code on this page was developed using the following requirements. We recommend using these versions or newer.

qiskit[all]~=2.4.0
qiskit-ibm-runtime~=0.46.1

You can use options to customize the Sampler primitive. This section focuses on how to specify Qiskit Runtime primitive options. While the interface of the primitives' run() method is common across all implementations, their options are not. Consult the corresponding API references for information about the qiskit.primitives.BackendSamplerV2 and qiskit_aer.primitives.SamplerV2 options.

Set Sampler options

You can set options when initializing Sampler, after initializing Sampler, or you can update the options after Sampler has been initialized. For instructions to use these techniques, see the Introduction to options topic.

Additionally, you can set the shots value in the run() method, as is described in the following section.

Run() method

The only values you can pass to run() are those defined in the interface. That is, shots. This overwrites any value set for default_shots for the current run.

# Added by doQumentation — required packages for this notebook
!pip install -q qiskit qiskit-ibm-runtime

from qiskit_ibm_runtime import QiskitRuntimeService
from qiskit_ibm_runtime import SamplerV2 as Sampler
from qiskit.circuit.library import random_iqp
from qiskit.transpiler import generate_preset_pass_manager

service = QiskitRuntimeService()
backend = service.least_busy(operational=True, simulator=False)

circuit1 = random_iqp(3)
circuit1.measure_all()
circuit2 = random_iqp(3)
circuit2.measure_all()

pass_manager = generate_preset_pass_manager(
    optimization_level=3, backend=backend
)

transpiled1 = pass_manager.run(circuit1)
transpiled2 = pass_manager.run(circuit2)

sampler = Sampler(mode=backend)
# Default shots to use if not specified in run()
sampler.options.default_shots = 500
# Sample two circuits at 128 shots each.
sampler.run([transpiled1, transpiled2], shots=128)

<RuntimeJobV2('d8286680bvlc73d1vmu0', 'sampler')>

Special cases

Shots

The SamplerV2.run method accepts two arguments: a list of PUBs, each of which can specify a PUB-specific value for shots, and a shots keyword argument. These shot values are a part of the Sampler execution interface, and are independent of the Runtime Sampler's options. They take precedence over any values specified as options in order to comply with the Sampler abstraction.

However, if shots is not specified by any PUB or in the run keyword argument (or if they are all None), then the shots value from the options is used, most notably default_shots.

To summarize, this is the order of precedence for specifying shots in the Sampler, for any particular PUB:

1. If the PUB specifies shots, use that value.
2. If the shots keyword argument is specified in run, use that value.
3. If twirling is enabled (True by default), then the product of num_randomizations and shots_per_randomization, as specified as twirling options, is used.
4. If sampler.options.default_shots is specified, use that value.

Thus, if shots are specified in all possible places, the one with highest precedence (shots specified in the PUB) is used.

Example:

from qiskit_ibm_runtime import QiskitRuntimeService
from qiskit_ibm_runtime import SamplerV2 as Sampler
from qiskit.circuit.library import random_iqp
from qiskit.transpiler import generate_preset_pass_manager

service = QiskitRuntimeService()
backend = service.least_busy(operational=True, simulator=False)

circuit1 = random_iqp(3)
circuit1.measure_all()
circuit2 = random_iqp(3)
circuit2.measure_all()

pass_manager = generate_preset_pass_manager(
    optimization_level=3, backend=backend
)

transpiled1 = pass_manager.run(circuit1)
transpiled2 = pass_manager.run(circuit2)

# Setting shots during primitive initialization
sampler = Sampler(mode=backend, options={"default_shots": 4096})

# Setting options after primitive initialization
# This uses auto-complete.
sampler.options.default_shots = 2000

# This does bulk update.  The value for default_shots is overridden if you specify shots with run() or in the PUB.
sampler.options.update(
    default_shots=1024, dynamical_decoupling={"sequence_type": "XpXm"}
)

# Sample two circuits at 128 shots each.
sampler.run([transpiled1, transpiled2], shots=128)

<RuntimeJobV2('d82868ugbeec73alfa80', 'sampler')>

Available options

The following table documents options from the latest version of qiskit-ibm-runtime. To see older option versions, visit the qiskit-ibm-runtime API reference and select a previous version.

`default_shots`

The total number of shots to use per circuit per configuration.

Choices: Integer >= 0

Default: None

default_shots API documentation

`dynamical_decoupling`

Control dynamical decoupling error mitigation settings.

dynamical_decoupling API documentation

`dynamical_decoupling.enable`

Choices: True, False

Default: False

`dynamical_decoupling.extra_slack_distribution`

Choices: middle, edges

Default: middle

`dynamical_decoupling.scheduling_method`

Choices: asap, alap Default: alap

`dynamical_decoupling.sequence_type`

Choices: XX, XpXm, XY4 Default: XX

`dynamical_decoupling.skip_reset_qubits`

Choices: True, False Default: False

`environment`

environment API documentation

`environment.job_tags`

List of tags.

Choices: None

Default: None

`environment.log_level`

Choices: DEBUG, INFO, WARNING, ERROR, CRITICAL

Default: WARNING

`environment.private`

Choices: True, False

Default: False

`execution`

execution API documentation

`execution.init_qubits`

Whether to reset the qubits to the ground state for each shot.

Choices: True, False

Default: True

`execution.rep_delay`

The delay between a measurement and the subsequent quantum circuit.

Choices: Value in the range supplied by backend.rep_delay_range

Default: Given by backend.default_rep_delay

`execution.meas_type`

Choices: classified, kerneled, avg_kerneled

Default: classified

`max_execution_time`

Limits how long a job can run, in seconds. See the maximum execution time guide for details.

Choices: Integer number of seconds in the range [1, 10800]

Default: 10800 (3 hours)

max_execution_time API documentation

`simulator`

Options to pass when simulating a backend

simulator API documentation

`simulator.basis_gates`

Choices: List of basis gate names to unroll to

Default: The set of all basis gates supported by Qiskit Aer simulator

`simulator.coupling_map`

Choices: List of directed two-qubit interactions

Default: None, which implies no connectivity constraints (full connectivity).

`simulator.noise_model`

Choices: Qiskit Aer NoiseModel, or its representation

Default: None

`simulator.seed_simulator`

Choices: Integer

Default: None

`twirling`

Twirling options

twirling API documentation

`twirling.enable_gates`

Choices: True, False

Default: False

`twirling.enable_measure`

Choices: True, False

Default: False

`twirling.num_randomizations`

Choices: auto, Integer >= 1

Default: auto

`twirling.shots_per_randomization`

Choices: auto, Integer >= 1

Default: auto

`twirling.strategy`

Choices: active, active-circuit, active-accum, all

Default: active-accum

`experimental`

Experimental options, when available.

Feature compatibility

Certain runtime features cannot be used together in a single job. Click the appropriate tab for a list of features that are incompatible with the selected feature:

Dynamic circuits

Incompatible with:

• Dynamical decoupling

Other notes:

• Gate twirling can be applied to dynamic circuits, but only to gates not inside conditional blocks. Measurement twirling can only be applied to terminal measurements.
• Compatible with fractional gates when using qiskit-ibm-runtime v0.42.0 or later.

Dynamical decoupling

Incompatible with dynamic circuits.

Fractional gates

Incompatible with:

• Gate twirling

Compatible with dynamic circuits when using qiskit-ibm-runtime v0.42.0 or later.

Gate twirling

Incompatible with fractional gates or with stretches.

Other notes:

• Gate twirling can be applied to dynamic circuits, but only to gates not inside conditional blocks. Measurement twirling can only be applied to terminal measurements.
• Does not work with non-Clifford entanglers.

Next steps

Recommendations

• Review the Introduction to options guide.
• Find more details about the SamplerV2 methods in the Sampler API reference.
• Decide what execution mode to run your job in.
• Learn about noise management with Sampler.