Source code for negmas.preferences.prob.locscale

from __future__ import annotations
from negmas.helpers.prob import ScipyDistribution
from negmas.outcomes import Outcome

from ..crisp_ufun import UtilityFunction
from ..mixins import StationaryMixin
from ..prob_ufun import ProbUtilityFunction

__all__ = ["ILSUtilityFunction", "UniformUtilityFunction"]




class ILSUtilityFunction(StationaryMixin, ProbUtilityFunction):
    """
    A utility function which represents the loc and scale deviations as any crisp ufun
    """

    def __init__(
        self, type: str, loc: UtilityFunction, scale: UtilityFunction, *args, **kwargs
    ):
        super().__init__(*args, **kwargs)
        self._type = type
        self.loc = loc
        self.scale = scale



    def eval(self, offer: Outcome) -> ScipyDistribution:
        loc, scale = self.loc(offer), self.scale(offer)
        if loc is None or scale is None:
            raise ValueError(
                f"Cannot calculate loc ({loc}) or scale ({scale}) for offer {offer}"
            )
        return ScipyDistribution(self._type, loc=loc, scale=scale)






class UniformUtilityFunction(ILSUtilityFunction):
    """
    A utility function which represents the loc and scale deviations as any crisp ufun
    """

    def __init__(self, loc: UtilityFunction, scale: UtilityFunction, *args, **kwargs):
        super().__init__("uniform", loc, scale, *args, *kwargs)



class GaussianUtilityFunction(ILSUtilityFunction):
    """
    A utility function which represents the mean and std deviations as any crisp ufun
    """

    def __init__(self, loc: UtilityFunction, scale: UtilityFunction, *args, **kwargs):
        super().__init__("norm", loc, scale, *args, *kwargs)


NormalUtilityFunction = GaussianUtilityFunction
"""
An alias for `GaussianUtilityFunction`
"""