Configure noise management with Estimator
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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-ibm-runtime~=0.46.1
There are several ways to manage noise, typically by using various error mitigation and error suppression techniques to avoid errors before they happen. These techniques usually cause pre-processing overhead. Therefore, it is important to achieve a balance between perfecting your results and ensuring that your job completes in a reasonable amount of time.
Estimator supports the following noise management techniques. See Error mitigation and suppression techniques for an explanation of each. See the Custom error settings section for instructions to enable these techniques.
Resilience level
The resilience_level specifies how much resilience to build against
errors. Higher levels generate more accurate results, at the expense of
longer processing times. Resilience levels can be used to configure the
cost/accuracy trade-off when applying noise management to your primitive
query. Noise management reduces errors (bias) in results by processing
the outputs from a collection, or ensemble, of related circuits. The
degree of error reduction depends on the method applied. The resilience
level abstracts the detailed choice of noise management method to allow
users to reason about the cost/accuracy trade that is appropriate to
their application.
Given this, each level corresponds to a method or methods with increasing level of quantum sampling overhead to enable you experiment with different time-accuracy tradeoffs. The following table shows you which levels and corresponding methods are available for each of the primitives.
| Resilience Level | Description | Technique |
|---|---|---|
| 0 | No mitigation | None |
| 1 [Default] | Minimal mitigation costs: Mitigate error associated with readout errors | Twirled Readout Error eXtinction (TREX) measurement twirling |
| 2 | Medium mitigation costs. Typically reduces bias in estimators, but is not guaranteed to be zero-bias. | Level 1 + Zero Noise Extrapolation (ZNE) and gate twirling |
Resilience levels are currently in beta so sampling overhead and solution quality will vary from circuit to circuit. New features, advanced options, and management tools will be released on a rolling basis. Specific noise management methods are not guaranteed to be applied at each resilience level.
Configure Estimator with resilience levels
You can use resilience levels to specify noise management techniques, or you can set custom techniques individually as described in Custom error settings.
Any options you manually specify in addition to the resilience level are applied in addition to 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.
For example, setting the resilience level to 0 turns off zne_mitigation, but estimator.options.resilience.zne_mitigation = True overrides that value.
Example
The following code enables ZNE, TREX, and gate twirling by
setting resilience_level 2.
# Added by doQumentation — required packages for this notebook
!pip install -q qiskit-ibm-runtime
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})
Custom noise management settings
You can turn on and off individual noise management methods by using the Estimator options.
Not all options work together on all types of circuits. See the feature compatibility table for details.
Example
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(backend)
options = estimator.options
# Turn on gate twirling.
options.twirling.enable_gates = True
# Turn on measurement error mitigation.
options.resilience.measure_mitigation = True
print(
f">>> gate twirling is turned on: {estimator.options.twirling.enable_gates}"
)
print(
f">>> measurement error mitigation is turned on: {estimator.options.resilience.measure_mitigation}"
)
>>> gate twirling is turned on: True
>>> measurement error mitigation is turned on: True
Turn off all error mitigation
For instructions to turn off all error mitigation see the Turn off all error suppression and mitigation section in the Estimator options guide.
Next steps
- Walk through an example that uses error mitigation in the Cost function lesson in IBM Quantum Learning.
- Learn more about error mitigation and error suppression techniques.
- Explore Estimator options.
- Decide what execution mode to run your job in.