Source code for feets.extractors.ext_stetson_k
#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Copyright (c) 2017-2024, Cabral, Juan
# Copyright (c) 2025, QuatroPe; Clariá, Felipe
# License: MIT
# Full Text:
# https://github.com/quatrope/feets/blob/master/LICENSE
# =============================================================================
# DOC
# =============================================================================
"""Stetson K extractor."""
# =============================================================================
# IMPORTS
# =============================================================================
from light_curve import StetsonK as _StetsonK
from .light_curve_extractor import LightCurveExtractor
from ..libs import doctools
# =============================================================================
# EXTRACTOR CLASS
# =============================================================================
[docs]
class StetsonK(LightCurveExtractor):
r"""Stetson K coefficient described light curve shape.
.. math::
\mathrm{Stetson}~K =
\frac{
\sum_i\left|\frac{m_i - \bar{m}
}{
\delta_i}\right|}{\sqrt{N\,\chi^2}
}
where :math:`N` is the number of observations, :math:`\bar{m}` is the
weighted mean magnitude, and
.. math::
\chi^2 =
\sum_i\left(
\frac{m_i - \langle m \rangle}{\delta_i}\right
)^2
Parameters
----------
transform : str or bool or None, optional
Transformer to apply to the feature values. If str, must be one of:
- 'default' - use default transformer for the feature, it same as
giving True. The default for this feature is 'identity'
- 'arcsinh' - Hyperbolic arcsine feature transformer
- 'clipped_lg' - Decimal logarithm of a value clipped to a minimum
value
- 'identity' - Identity feature transformer
- 'lg' - Decimal logarithm feature transformer
- 'ln1p' - :math:`ln(1+x)` feature transformer
- 'sqrt' - Square root feature transformer
If bool, must be True to use default transformer or False to disable.
If None, no transformation is applied.
References
----------
.. [stetson1996automatic] Stetson, P. B. (1996). On the Automatic
Determination of Light-Curve Parameters for Cepheid Variables.
Publications of the Astronomical Society of the Pacific, 108(728),
851-876. http://www.jstor.org/stable/40680814
"""
features = ["StetsonK"]
def __init__(self, transform=None):
self.transform = transform
self._extract = _StetsonK(**self.params)
