"""GammaUnivariate module."""
import numpy as np
from scipy.stats import gamma
from copulas.univariate.base import BoundedType, ParametricType, ScipyModel
[docs]class GammaUnivariate(ScipyModel):
"""Wrapper around scipy.stats.gamma.
Documentation: https://docs.scipy.org/doc/scipy/reference/generated/scipy.stats.gamma.html
"""
PARAMETRIC = ParametricType.PARAMETRIC
BOUNDED = BoundedType.SEMI_BOUNDED
MODEL_CLASS = gamma
def _fit_constant(self, X):
self._params = {
'a': 0.0,
'loc': np.unique(X)[0],
'scale': 0.0,
}
def _fit(self, X):
a, loc, scale = gamma.fit(X)
self._params = {
'a': a,
'loc': loc,
'scale': scale,
}
def _is_constant(self):
return self._params['scale'] == 0
def _extract_constant(self):
return self._params['loc']