sigclip_combine_1d

sigclip_combine_1d(
    values,
    *,
    mask=None,
    combine,
    sigma=(3.0, 3.0),
    maxiters=5,
    ddof=0,
    nkeep=0,
    maxrej=None,
    cenfunc='median',
    clip_cen=None,
    stdfunc='std',
    revert_on_nkeep=False,
    validate=True,
)

Return a 1-D sigma-clipped mean or median.

Parameters

values : (ndarray, shape(N)): One sample vector.
mask : ndarray or None = None: Same shape as the input; True excludes a sample. Default None.
sigma : float or (float, float) = (3.0, 3.0): Finite, nonnegative lower and upper multipliers; default (3.0, 3.0). Samples exactly on a threshold survive.
maxiters : int = 5: Maximum attempted passes; default 5. 0 applies initial exclusions only.
ddof : int = 0: Divide squared deviations by n - ddof; default 0. Ignored for MAD. Undefined statistics stop the current pass without changing the mask.
nkeep : int = 0: Rollback minimum, active only with revert_on_nkeep=True; default 0. This is not a final minimum-count requirement.
maxrej : int or None = None: Roll back a pass if total exclusions exceed this count. Counts input masks and nonfinite samples as well as clipping; default None (unlimited).
cenfunc : str = 'median': Rejection center: "median" (default), "lmedian", or "mean".
clip_cen : str or None = None: Dispersion center: "mean", "median", "lmedian", or "cenfunc" to use the computed rejection center directly. None follows cenfunc’s estimator, preserving its arithmetic; default None.
stdfunc : str = 'std': "std" (default) or "mad" (median absolute deviation times 1.4826).
revert_on_nkeep : bool = False: Enable whole-pass survivor rollback; default False. Earlier accepted rejections and initial exclusions remain after rollback.
combine : str: Required statistic: "mean", "average", "avg", "median", or "med".
validate : bool = True: Validate/promote arrays; default True. With False, supply a 1-D float32/float64 vector.

Returns

value : float: Clipped mean or median; NaN if none survive.

Notes

NaN, infinities, and input masks are excluded before clipping. Inputs are never modified. Accepted rejections accumulate. Empty/all-excluded inputs have all-excluded masks, NaN extrema/spread, and NaN fused reductions.

With validate=True, float32 and float64 are preserved; uint8, uint16, and int16 use float32, and int32 uses float64. Other dtypes are rejected. Noncontiguous input is copied only when needed. Centers and MAD round to the input dtype before threshold comparisons. Squared residuals and limits can overflow or underflow.