BaseCoherenceFitter¶

class BaseCoherenceFitter(description, backend_result, xdata, qubits, fit_fun, fit_p0, fit_bounds, circuit_names, series=None, expected_state='0', time_index=0, time_unit='micro-seconds')[source]¶

Bases: qiskit.ignis.characterization.fitters.BaseFitter

Base class for fitters of characteristic times

Parameters

description (str) – description of the fitter’s purpose, e.g. ‘T1’.
backend_result (Union[Result, List[Result]]) – result of execution on the backend.
xdata (Union[List[float], array]) – delay times of the circuits.
qubits (List[int]) – the qubits to be characterized.
fit_fun (Callable[…, float]) – equivalent to parameter f of scipy.curve_fit.
fit_p0 (List[float]) – equivalent to parameter p0 of scipy.curve_fit.
fit_bounds (Tuple[List[float], List[float]]) – equivalent to parameter bounds of scipy.curve_fit.
circuit_names (List[str]) – names of the circuits, should be the same length as xdata. Full circuit name will be these plus the series name.
series (Optional[List[str]]) – list of circuit name tags
expected_state (str) – is the circuit supposed to end up in ‘0’ or ‘1’?
time_index (int) – among parameters of fit_fun, which one is the characteristic time.
time_unit (str) – unit of delay times in xdata.

Methods

`add_data`	Add new execution results to previous execution results
`fit_data`	Fit the curve.
`plot`	Plot coherence data.
`time`	Return the characteristic time for the given qubit and series
`time_err`	Return the error of characteristic time for the given qubit and series

Attributes

backend_result¶

Return the execution results

Return type: Union[Result, List[Result]]

description¶

Return the fitter’s purpose, e.g. ‘T1’

Return type: str

fit_fun¶

Return the function used in the fit, e.g. BaseFitter._exp_fit_fun

Return type: Callable

measured_qubits¶

Return the indices of the qubits to be characterized

Return type: List[int]

params¶

Return the fit function parameters that were calculated by curve_fit

Return type: List[float]

params_err¶

Return the error of the fit function parameters

Return type: List[float]

series¶

Return the list of series for the data

Return type: Optional[List[str]]

xdata¶

Return the data points on the x-axis, the independenet parameter which is fit against

Return type: Union[List[float], array]

ydata¶

Return the data points on the y-axis

The data points are returning in the form of a list of dictionaries:

ydata[i][‘mean’] is a list, where item
no. j is the probability of success of qubit i for a circuit that lasts xdata[j].

ydata[i][‘std’] is a list, where ydata[‘std’][j] is the
standard deviation of the success of qubit i.

Return type: List[Dict]