cirq.google.PhasedFSimEngineSimulator

View source on GitHub

Wrapper on top of cirq.Simulator that allows to simulate calibration requests.

Inherits From: SimulatesSamples, Sampler, SimulatesIntermediateStateVector, SimulatesAmplitudes, SimulatesIntermediateState, SimulatesFinalState

View aliases

Main aliases

cirq.google.calibration.PhasedFSimEngineSimulator, cirq.google.calibration.engine_simulator.PhasedFSimEngineSimulator

cirq.google.PhasedFSimEngineSimulator(
    simulator: cirq.sim.Simulator,
    *,
    drift_generator: cirq.google.calibration.engine_simulator.ParametersDriftGenerator = try_convert_sqrt_iswap_to_fsim,
    gates_translator: Callable[[Gate], Optional[PhaseCalibratedFSimGate]] = cirq.google.try_convert_sqrt_iswap_to_fsim
) -> None

Used in the notebooks

Used in the tutorials
Floquet calibration

This simulator introduces get_calibrations which allows to simulate cirq.google.run_characterizations requests. The returned calibration results represent the internal state of a simulator. Circuits which are run on this simulator are modified to account for the changes in the unitary parameters as described by the calibration results.

Args
simulator	cirq.Simulator that all the simulation requests are delegated to.
drift_generator	Callable that generates the imperfect parameters for each pair of qubits and the gate. They are later used for simulation.
gates_translator	Function that translates a gate to a supported FSimGate which will undergo characterization.

Attributes
gates_translator	Function that translates a gate to a supported FSimGate which will undergo characterization.

Methods

compute_amplitudes

View source

compute_amplitudes(
    program: "cirq.Circuit",
    bitstrings: Sequence[int],
    param_resolver: "study.ParamResolverOrSimilarType" = None,
    qubit_order: cirq.ops.QubitOrderOrList = cirq.ops.QubitOrder.DEFAULT
) -> Sequence[complex]

Computes the desired amplitudes.

The initial state is assumed to be the all zeros state.

Args
program	The circuit to simulate.
bitstrings	The bitstrings whose amplitudes are desired, input as an integer array where each integer is formed from measured qubit values according to qubit_order from most to least significant qubit, i.e. in big-endian ordering.
param_resolver	Parameters to run with the program.
qubit_order	Determines the canonical ordering of the qubits. This is often used in specifying the initial state, i.e. the ordering of the computational basis states.

Returns
List of amplitudes.

compute_amplitudes_sweep

View source

compute_amplitudes_sweep(
    program: "cirq.Circuit",
    bitstrings: Sequence[int],
    params: cirq.study.Sweepable,
    qubit_order: cirq.ops.QubitOrderOrList = cirq.ops.QubitOrder.DEFAULT
) -> Sequence[Sequence[complex]]

Computes the desired amplitudes.

The initial state is assumed to be the all zeros state.

Args
program	The circuit to simulate.
bitstrings	The bitstrings whose amplitudes are desired, input as an integer array where each integer is formed from measured qubit values according to qubit_order from most to least significant qubit, i.e. in big-endian ordering.
params	Parameters to run with the program.
qubit_order	Determines the canonical ordering of the qubits. This is often used in specifying the initial state, i.e. the ordering of the computational basis states.

Returns
List of lists of amplitudes. The outer dimension indexes the circuit parameters and the inner dimension indexes the bitstrings.

create_from_characterizations_sqrt_iswap

View source

@classmethod
create_from_characterizations_sqrt_iswap(
    characterizations: Iterable[cirq.google.PhasedFSimCalibrationResult],
    *,
    simulator: Optional[cirq.sim.Simulator] = None,
    ideal_when_missing_gate: bool = False,
    ideal_when_missing_parameter: bool = False
) -> "PhasedFSimEngineSimulator"

Creates PhasedFSimEngineSimulator with fixed drifts from the characterizations results.

Args
characterizations	Characterization results which are source of the parameters for each gate.
simulator	Simulator object to use. When None, a new instance of cirq.Simulator() will be created.
ideal_when_missing_gate	When set and parameters for some gate for a given pair of qubits are not specified in the parameters dictionary then the FSimGate(theta=π/4, phi=0) gate parameters will be used. When not set and this situation occurs, ValueError is thrown during simulation.
ideal_when_missing_parameter	When set and some parameter for some gate for a given pair of qubits is specified then the matching parameter of FSimGate(theta=π/4, phi=0) gate will be used. When not set and this situation occurs, ValueError is thrown during simulation.

Returns
New PhasedFSimEngineSimulator instance.

create_from_dictionary_sqrt_iswap

View source

@classmethod
create_from_dictionary_sqrt_iswap(
    parameters: cirq.google.calibration.engine_simulator.PhasedFsimDictParameters,
    *,
    simulator: Optional[cirq.sim.Simulator] = None,
    ideal_when_missing_gate: bool = False,
    ideal_when_missing_parameter: bool = False
) -> "PhasedFSimEngineSimulator"

Creates PhasedFSimEngineSimulator with fixed drifts.

Args
parameters	Parameters to use for each gate. All keys must be stored in canonical order, when the first qubit is not greater than the second one.
simulator	Simulator object to use. When None, a new instance of cirq.Simulator() will be created.
ideal_when_missing_gate	When set and parameters for some gate for a given pair of qubits are not specified in the parameters dictionary then the FSimGate(theta=π/4, phi=0) gate parameters will be used. When not set and this situation occurs, ValueError is thrown during simulation.
ideal_when_missing_parameter	When set and some parameter for some gate for a given pair of qubits is specified then the matching parameter of FSimGate(theta=π/4, phi=0) gate will be used. When not set and this situation occurs, ValueError is thrown during simulation.

Returns
New PhasedFSimEngineSimulator instance.

create_gate_with_drift

View source

create_gate_with_drift(
    a: cirq.ops.Qid,
    b: cirq.ops.Qid,
    gate_calibration: cirq.google.calibration.phased_fsim.PhaseCalibratedFSimGate
) -> cirq.ops.PhasedFSimGate

Generates a gate with drift for a given gate.

Args
a	The first qubit.
b	The second qubit.
gate_calibration	Reference gate together with a phase information.

Returns
A modified gate that includes the drifts induced by internal state of the simulator.

create_with_ideal_sqrt_iswap

View source

@classmethod
create_with_ideal_sqrt_iswap(
    *,
    simulator: Optional[cirq.sim.Simulator] = None
) -> "PhasedFSimEngineSimulator"

Creates a PhasedFSimEngineSimulator that simulates ideal FSimGate(theta=π/4, phi=0).

Attributes
simulator	Simulator object to use. When None, a new instance of cirq.Simulator() will be created.

Returns
New PhasedFSimEngineSimulator instance.

create_with_random_gaussian_sqrt_iswap

View source

@classmethod
create_with_random_gaussian_sqrt_iswap(
    mean: cirq.google.PhasedFSimCharacterization = cirq.google.SQRT_ISWAP_PARAMETERS,
    *,
    simulator: Optional[cirq.sim.Simulator] = None,
    sigma: cirq.google.PhasedFSimCharacterization = PhasedFSimCharacterization(theta=0.02, zeta=0.05, chi=0.05, gamma=0.05, phi\n    =0.02),
    random_or_seed: RANDOM_STATE_OR_SEED_LIKE = None
) -> "PhasedFSimEngineSimulator"

Creates a PhasedFSimEngineSimulator that introduces a random deviation from the mean.

The random deviations are described by a Gaussian distribution of a given mean and sigma, for each angle respectively.

Each gate for each pair of qubits retains the sampled values for the entire simulation, even when used multiple times within a circuit.

Attributes
mean	The mean value for each unitary angle. All parameters must be provided.
simulator	Simulator object to use. When None, a new instance of cirq.Simulator() will be created.
sigma	The standard deviation for each unitary angle. For sigma parameters that are None, the mean value will be used without any sampling.

Returns
New PhasedFSimEngineSimulator instance.

final_state_vector

View source

final_state_vector(
    program: cirq.circuits.Circuit
) -> np.array

get_calibrations

View source

get_calibrations(
    requests: Sequence[cirq.google.PhasedFSimCalibrationRequest]
) -> List[cirq.google.PhasedFSimCalibrationResult]

Retrieves the calibration that matches the requests

Args
requests	Calibration requests to obtain.

Returns
Calibration results that reflect the internal state of simulator.

run

View source

run(
    program: "cirq.Circuit",
    param_resolver: "cirq.ParamResolverOrSimilarType" = None,
    repetitions: int = 1
) -> "cirq.Result"

Samples from the given Circuit.

By default, the run_async method invokes this method on another thread. So this method is supposed to be thread safe.

Args
program	The circuit to sample from.
param_resolver	Parameters to run with the program.
repetitions	The number of times to sample.

Returns
Result for a run.

run_async

View source

run_async(
    program, *, repetitions
)

Asynchronously samples from the given Circuit.

By default, this method invokes run synchronously and simply exposes its result is an awaitable. Child classes that are capable of true asynchronous sampling should override it to use other strategies.

Args
program	The circuit to sample from.
repetitions	The number of times to sample.

Returns
An awaitable Result.

run_batch

View source

run_batch(
    programs: List['cirq.Circuit'],
    params_list: Optional[List['cirq.Sweepable']] = None,
    repetitions: Union[int, List[int]] = 1
) -> List[List['cirq.Result']]

Runs the supplied circuits.

Each circuit provided in programs will pair with the optional associated parameter sweep provided in the params_list, and be run with the associated repetitions provided in repetitions (if repetitions is an integer, then all runs will have that number of repetitions). If params_list is specified, then the number of circuits is required to match the number of sweeps. Similarly, when repetitions is a list, the number of circuits is required to match the length of this list.

By default, this method simply invokes run_sweep sequentially for each (circuit, parameter sweep, repetitions) tuple. Child classes that are capable of sampling batches more efficiently should override it to use other strategies. Note that child classes may have certain requirements that must be met in order for a speedup to be possible, such as a constant number of repetitions being used for all circuits. Refer to the documentation of the child class for any such requirements.

Args
programs	The circuits to execute as a batch.
params_list	Parameter sweeps to use with the circuits. The number of sweeps should match the number of circuits and will be paired in order with the circuits.
repetitions	Number of circuit repetitions to run. Can be specified as a single value to use for all runs, or as a list of values, one for each circuit.

Returns
A list of lists of TrialResults. The outer list corresponds to the circuits, while each inner list contains the TrialResults for the corresponding circuit, in the order imposed by the associated parameter sweep.

run_sweep

View source

run_sweep(
    program: "cirq.Circuit",
    params: cirq.study.Sweepable,
    repetitions: int = 1
) -> List[cirq.study.Result]

Runs the supplied Circuit, mimicking quantum hardware.

In contrast to run, this allows for sweeping over different parameter values.

Args
program	The circuit to simulate.
params	Parameters to run with the program.
repetitions	The number of repetitions to simulate.

Returns
Result list for this run; one for each possible parameter resolver.

run_sweep_async

View source

run_sweep_async(
    program, params, repetitions=1
)

Asynchronously sweeps and samples from the given Circuit.

By default, this method invokes run_sweep synchronously and simply exposes its result is an awaitable. Child classes that are capable of true asynchronous sampling should override it to use other strategies.

Args
program	The circuit to sample from.
params	One or more mappings from parameter keys to parameter values to use. For each parameter assignment, repetitions samples will be taken.
repetitions	The number of times to sample.

Returns
An awaitable Result.

sample

View source

sample(
    program: "cirq.Circuit",
    *,
    repetitions: int = 1,
    params: "cirq.Sweepable" = None
) -> "pd.DataFrame"

Samples the given Circuit, producing a pandas data frame.

Args
program	The circuit to sample from.
repetitions	The number of times to sample the program, for each parameter mapping.
params	Maps symbols to one or more values. This argument can be a dictionary, a list of dictionaries, a cirq.Sweep, a list of cirq.Sweep, etc. The program will be sampled repetition times for each mapping. Defaults to a single empty mapping.

Returns

A pandas.DataFrame with a row for each sample, and a column for each measurement key as well as a column for each symbolic parameter. Measurement results are stored as a big endian integer representation with one bit for each measured qubit in the key. See cirq.big_endian_int_to_bits and similar functions for how to convert this integer into bits. There is an also index column containing the repetition number, for each parameter assignment.

Examples:

a, b, c = cirq.LineQubit.range(3)
sampler = cirq.Simulator()
circuit = cirq.Circuit(cirq.X(a),
                       cirq.measure(a, key='out'))
print(sampler.sample(circuit, repetitions=4))
   out
0    1
1    1
2    1
3    1

circuit = cirq.Circuit(cirq.X(a),
                       cirq.CNOT(a, b),
                       cirq.measure(a, b, c, key='out'))
print(sampler.sample(circuit, repetitions=4))
   out
0    6
1    6
2    6
3    6

circuit = cirq.Circuit(cirq.X(a)**sympy.Symbol('t'),
                       cirq.measure(a, key='out'))
print(sampler.sample(
    circuit,
    repetitions=3,
    params=[{'t': 0}, {'t': 1}]))
   t  out
0  0    0
1  0    0
2  0    0
0  1    1
1  1    1
2  1    1

simulate

View source

simulate(
    program: "cirq.Circuit",
    param_resolver: "study.ParamResolverOrSimilarType" = None,
    qubit_order: cirq.ops.QubitOrderOrList = cirq.ops.QubitOrder.DEFAULT,
    initial_state: Any = None
) -> cirq.sim.simulator.TSimulationTrialResult

Simulates the supplied Circuit.

This method returns a result which allows access to the entire simulator's final state.

Args
program	The circuit to simulate.
param_resolver	Parameters to run with the program.
qubit_order	Determines the canonical ordering of the qubits. This is often used in specifying the initial state, i.e. the ordering of the computational basis states.
initial_state	The initial state for the simulation. The form of this state depends on the simulation implementation. See documentation of the implementing class for details.

Returns
SimulationTrialResults for the simulation. Includes the final state.

simulate_moment_steps

View source

simulate_moment_steps(
    circuit: cirq.circuits.Circuit,
    param_resolver: "study.ParamResolverOrSimilarType" = None,
    qubit_order: cirq.ops.QubitOrderOrList = cirq.ops.QubitOrder.DEFAULT,
    initial_state: Any = None
) -> Iterator[cirq.sim.simulator.TStepResult]

Returns an iterator of StepResults for each moment simulated.

If the circuit being simulated is empty, a single step result should be returned with the state being set to the initial state.

Args
circuit	The Circuit to simulate.
param_resolver	A ParamResolver for determining values of Symbols.
qubit_order	Determines the canonical ordering of the qubits. This is often used in specifying the initial state, i.e. the ordering of the computational basis states.
initial_state	The initial state for the simulation. The form of this state depends on the simulation implementation. See documentation of the implementing class for details.

Returns
Iterator that steps through the simulation, simulating each moment and returning a StepResult for each moment.

simulate_sweep

View source

simulate_sweep(
    program: "cirq.Circuit",
    params: cirq.study.Sweepable,
    qubit_order: cirq.ops.QubitOrderOrList = cirq.ops.QubitOrder.DEFAULT,
    initial_state: Any = None
) -> List[cirq.sim.simulator.TSimulationTrialResult]

Simulates the supplied Circuit.

This method returns a result which allows access to the entire state vector. In contrast to simulate, this allows for sweeping over different parameter values.

Args
program	The circuit to simulate.
params	Parameters to run with the program.
qubit_order	Determines the canonical ordering of the qubits. This is often used in specifying the initial state, i.e. the ordering of the computational basis states.
initial_state	The initial state for the simulation. The form of this state depends on the simulation implementation. See documentation of the implementing class for details.

Returns
List of SimulationTrialResults for this run, one for each possible parameter resolver.