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')
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
BaseCoherenceFitter.add_data(results, recalc=True, refit=True)
Add new execution results to previous execution results
Parameters
- results (
Union[Result,List[Result]]) – new execution results - recalc (
bool) – whether tp recalculate the data - refit (
bool) – whether to refit the data
fit_data
BaseCoherenceFitter.fit_data(qid=- 1, p0=None, bounds=None, series=None)
Fit the curve.
Compute self._params and self._params_err
Parameters
- qid (
int) – qubit for fitting. If -1 fit for all the qubits - p0 (
Optional[List[float]]) – initial guess, equivalent to p0 in scipy.optimize - bounds (
Optional[Tuple[List[float],List[float]]]) – bounds, equivalent to bounds in scipy.optimize - series (
Optional[str]) – series to fit (if None fit all)
plot
BaseCoherenceFitter.plot(qind, series, ax=None, show_plot=True)
Plot coherence data.
Parameters
- qind (
int) – qubit index to plot - series (
str) – which series to plot (if list then plot multiple) - ax (
Optional[Any]) – plot axes - show_plot (
bool) – whether to call plt.show()
Returns
The axes object
Return type
Axes
Raises
ImportError – if matplotlib is not installed
time
BaseCoherenceFitter.time(qid=- 1, series='0')
Return the characteristic time for the given qubit and series
Parameters
- qid (
int) – the qubit index (or all qubits if -1) - series (
str) – the series to get
Return type
Union[float, List[float]]
Returns
The characteristic time of the qubit, or all qubits
time_err
BaseCoherenceFitter.time_err(qid=- 1, series='0')
Return the error of characteristic time for the given qubit and series
Parameters
- qid (
int) – the qubit index (or all qubits if -1) - series (
str) – the series to get
Return type
Union[float, List[float]]
Returns
The error of the characteristic time of the qubit, or all qubits
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]