qspec.analyze. King.fit  (  a ,  a_ref ,  x = None ,  y = None ,  xy = None ,  func = 'york_fit' ,  alpha = 0 ,  find_alpha = False ,  show = True ,  ** kwargs  )[source]

Parameters:

andarray | Iterable

An Iterable of the mass numbers of the used isotopes.

a_refndarray | Iterable

An Iterable of the mass numbers of the used reference isotopes.

xndarray | Iterable

The x-values and their uncertainties of the King-fit to be performed. If 'mode' is "radii", this must contain the differences of mean square nuclear charge radii or the Lambda-factor. 'x' must have shape (len(a), 2). Units: (fm ** 2) or (MHz).

yndarray | Iterable

The isotope shifts and their uncertainties of the King-fit to be performed. 'y' must have shape (len(a), 2). If None, 'y' is tried to be inherited from 'self.f'. Units: (MHz).

xyIterable[int]

A 2-tuple of indices (ix, iy) which select the axes to use for the King-fit from 'King.x_abs' if x or y is not specified. The default value is (0, 1), fitting the second against the first axis.

funcstr | Callable

The fitting routine. Must be one of {'york_fit' (default), 'linear_fit', 'linear_monte_carlo'}.

alphascalar

An x-axis offset to reduce the correlation coefficient between the y-intercept and the slope. Unit: (u fm ** 2) or (u MHz).

find_alphabool

Whether to search for the best 'alpha'. Uses the given 'alpha' as a starting point. May not give the desired result if 'alpha' was initialized to far from its optimal value.

showbool

Whether to plot the fit result.

kwargsNone

Additional keyword arguments are passed to 'self.plot'.

Returns:

outNone

A list of results as defined by the routine 'linear_alpha': a, b, sigma_a, sigma_b, corr_ab, alpha. The best y-intercept and slope, their respective 1-sigma uncertainties, their correlation coefficient and the used alpha.