Specify options

You can use options to customize the Estimator and Sampler primitives. 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 and qiskit_aer.primitives options.

Notes about specifying options in the primitives:

• SamplerV2 and EstimatorV2 have separate options classes. You can see the available options and update option values during or after primitive initialization.
• Use the update() method to apply changes to the options attribute.
• If you do not specify a value for an option, it is given a special value of Unset and the server defaults are used.
• The options attribute is the dataclass Python type. You can use the built-in asdict method to convert it to a dictionary.

Set primitive options

You can set options when initializing the primitive, after initializing the primitive, or in the run() method. See the precedence rules section to understand what happens when the same option is specified in multiple places.

Primitive initialization

You can pass in an instance of the options class or a dictionary when initializing a primitive, which then makes a copy of those options. Thus, changing the original dictionary or options instance doesn't affect the options owned by the primitives.

Options class

When creating an instance of the EstimatorV2 or SamplerV2 class, you can pass in an instance of the options class. Those options will then be applied when you use run() to perform the calculation. Specify the options in this format: options.option.sub-option.sub-sub-option = choice. For example: options.dynamical_decoupling.enable = True

Example:

SamplerV2 and EstimatorV2 have separate options classes (EstimatorOptions and SamplerOptions).

from qiskit_ibm_runtime import QiskitRuntimeService
from qiskit_ibm_runtime import EstimatorV2 as Estimator
from qiskit_ibm_runtime.options import EstimatorOptions
 
service = QiskitRuntimeService()
backend = service.least_busy(operational=True, simulator=False)
 
options =  EstimatorOptions(resilience_level=2, resilience={"zne_mitigation": True, "zne": {"noise_factors": [1, 3, 5]}})
 
# or...
options =  EstimatorOptions()
options.resilience_level = 2
options.resilience.zne_mitigation = True
options.resilience.zne.noise_factors = [1, 3, 5]
 
estimator = Estimator(mode=backend, options=options)

Dictionary

You can specify options as a dictionary when initializing the primitive.

from qiskit_ibm_runtime import QiskitRuntimeService
from qiskit_ibm_runtime import EstimatorV2 as Estimator
 
service = QiskitRuntimeService()
backend = service.least_busy(operational=True, simulator=False)
 
# Setting options during primitive initialization
estimator = Estimator(backend, options={"resilience_level": 2, "resilience": {"zne_mitigation": True, "zne": {"noise_factors": [1, 3, 5]}}})

Update options after initialization

You can specify the options in this format: primitive.options.option.sub-option.sub-sub-option = choice to take advantage of auto-complete, or use the update() method to make bulk updates.

The SamplerV2 and EstimatorV2 options classes (EstimatorOptions and SamplerOptions) do not need to be instantiated if you are setting options after initializing the primitive.

from qiskit_ibm_runtime import QiskitRuntimeService
from qiskit_ibm_runtime import EstimatorV2 as Estimator
 
service = QiskitRuntimeService()
backend = service.least_busy(operational=True, simulator=False)
 
estimator = Estimator(mode=backend)
 
# Setting options after primitive initialization
# This uses auto-complete.
estimator.options.default_shots = 4000
# This does bulk update.
estimator.options.update(default_shots=4000, resilience={"zne_mitigation": True})

Run() method

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

from qiskit_ibm_runtime import QiskitRuntimeService
from qiskit_ibm_runtime import SamplerV2 as Sampler
 
service = QiskitRuntimeService()
backend = service.least_busy(operational=True, simulator=False)
 
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([circuit1, circuit2], shots=128)
 
# Sample two circuits with different numbers of shots.
# 100 shots is used for circuit1 and 200 for circuit2.
sampler.run([(circuit1, None, 100), (circuit2, None, 200)])

Special cases

Resilience level (Estimator only)

The resilience level is not actually an option that directly impacts the primitive query, but specifies a base set of curated options to build off of. In general, level 0 turns off all error mitigation, level 1 turns on options for measurement error mitigation, and level 2 turns on options for gate and measurement error mitigation.

Any options you manually specify in addition to the resilience level are applied on top of the base set of options defined by the resilience level. Therefore, in principle, you could set the resilience level to 1, but then turn off measurement mitigation, although this is not advised.

In the following example, setting the resilience level to 0 initially turns off zne_mitigation, but estimator.options.resilience.zne_mitigation = True overrides the relevent setup from estimator.options.resilience_level = 0.

from qiskit_ibm_runtime import EstimatorV2, QiskitRuntimeService
from qiskit import QuantumCircuit
 
service = QiskitRuntimeService()
backend = service.backend("ibm_auckland")
 
estimator = EstimatorV2(backend)
 
estimator.options.default_shots = 100
estimator.options.resilience_level = 0
estimator.options.resilience.zne_mitigation = True

Shots (Sampler only)

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.

Finally, because the twirling options num_randomizations and shots_per_randomization are enabled by default, the number of shots will actually be the product of num_randomizations and shots_per_randomization if the default_shots value is the only way shots are specified.

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 num_randomizations and shots_per_randomization are specified as twirling options (enabled by default), shots are the product of those values.
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.

Precision (Estimator only)

Precision is analogous to shots, described in the previous section, except that the Estimator options contain both default_shots and default_precision.

Specifically, for any particular Estimator PUB:

1. If the PUB specifies precision, use that value.
2. If the precision keyword argument is specified in run, use that value.
3. If num_randomizations and shots_per_randomization are specified as twirling options (enabled by default), use their product to control the amount of data.
4. If estimator.options.default_shots is specified, use that value to control the amount of data.
5. If estimator.options.default_precision is specified, use that value.

For example, if precision is specified in all four places, the one with highest precedence (precision specified in the PUB) is used.

Commonly used options

There are many available options, but the following are the most commonly used:

Shots

For some algorithms, setting a specific number of shots is a core part of their routines. Shots (or precision) can be specified in multiple places. They are prioritized as follows:

For any Sampler PUB:

1. Integer-valued shots contained in the PUB
2. The run(...,shots=val) value
3. The options.default_shots value

For any Estimator PUB:

1. Float-valued precision contained in the PUB
2. The run(...,precision=val) value
3. The options.default_shots value
4. The options.default_precision value

Example:

from qiskit_ibm_runtime import QiskitRuntimeService
from qiskit_ibm_runtime import SamplerV2 as Sampler
 
service = QiskitRuntimeService()
backend = service.least_busy(operational=True, simulator=False)
 
# 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([circuit1, circuit2], shots=128)

Maximum execution time

The maximum execution time (max_execution_time) limits how long a job can run. If a job exceeds this time limit, it is forcibly canceled. This value applies to single jobs, whether they are run in job, session, or batch mode.

The value is set in seconds, based on quantum time (not wall clock time), which is the amount of time that the QPU is dedicated to processing your job. It is ignored when using local testing mode because that mode does not use quantum time.

from qiskit_ibm_runtime import QiskitRuntimeService
from qiskit_ibm_runtime import EstimatorV2 as Estimator
 
service = QiskitRuntimeService()
backend = service.least_busy(operational=True, simulator=False)
 
estimator = Estimator(mode=backend)
 
estimator.options.max_execution_time = 2500

Turn off all error mitigation and error suppression

You can turn off all error mitigation and suppression if you are, for example, doing research on your own mitigation techniques. To accomplish this, for EstimatorV2, set resilience_level = 0. For SamplerV2, no changes are necessary because no error mitigation or suppression options are enabled by default.

Example:

Turn off all error mitigation and suppression in Estimator.

from qiskit_ibm_runtime import EstimatorV2 as Estimator, QiskitRuntimeService
 
# Define the service.  This allows you to access IBM QPU.
service = QiskitRuntimeService()
 
# Get a backend
backend = service.least_busy(operational=True, simulator=False)
 
# Define Estimator
estimator = Estimator(backend)
 
options = estimator.options
 
# Turn off all error mitigation and suppression
options.resilience_level = 0

Next steps