cirq_google.calibration.LocalXEBPhasedFSimCalibrationOptions

Options for configuring a PhasedFSim calibration using a local version of XEB.

Inherits From: XEBPhasedFSimCalibrationOptions, PhasedFSimCalibrationOptions

XEB uses the fidelity of random circuits to characterize PhasedFSim gates. The parameters of the gate are varied by a classical optimizer to maximize the observed fidelities.

These "Local" options (corresponding to LocalXEBPhasedFSimCalibrationRequest) instruct cirq_google.run_calibrations to execute XEB analysis locally (not via the quantum engine). As such, run_calibrations can work with any cirq.Sampler, not just QuantumEngineSampler.

n_library_circuits The number of distinct, two-qubit random circuits to use in our library of random circuits. This should be the same order of magnitude as n_combinations.
n_combinations We take each library circuit and randomly assign it to qubit pairs. This parameter controls the number of random combinations of the two-qubit random circuits we execute. Higher values increase the precision of estimates but linearly increase experimental runtime.
cycle_depths We run the random circuits at these cycle depths to fit an exponential decay in the fidelity.
fatol The absolute convergence tolerance for the objective function evaluation in the Nelder-Mead optimization. This controls the runtime of the classical characterization optimization loop.
xatol The absolute convergence tolerance for the parameter estimates in the Nelder-Mead optimization. This controls the runtime of the classical characterization optimization loop.
fsim_options An instance of XEBPhasedFSimCharacterizationOptions that controls aspects of the PhasedFSim characterization like initial guesses and which angles to characterize.
n_processes The number of multiprocessing processes to analyze the XEB characterization data. By default, we use a value equal to the number of CPU cores. If 1 is specified, multiprocessing is not used.

n_library_circuits Dataclass field
n_combinations Dataclass field
cycle_depths Dataclass field
fatol Dataclass field
xatol Dataclass field
fsim_options Dataclass field
n_processes Dataclass field

Methods

create_phased_fsim_request

View source

Create a PhasedFSimCalibrationRequest of the correct type for these options.

Args
pairs Set of qubit pairs to characterize. A single qubit can appear on at most one pair in the set.
gate Gate to characterize for each qubit pair from pairs. This must be a supported gate which can be described cirq.PhasedFSim gate. This gate must be serialized by the cirq_google.SerializableGateSet used

to_args

View source

Convert this dataclass to an args dictionary suitable for sending to the Quantum Engine calibration API.

__eq__

cycle_depths (5, 25, 50, 100, 200, 300)
fatol 0.005
fsim_options Instance of cirq.experiments.xeb_fitting.XEBPhasedFSimCharacterizationOptions
n_combinations 10
n_library_circuits 20
n_processes None
xatol 0.005