Source code for gamspy.math.probability

from __future__ import annotations

from typing import TYPE_CHECKING

import gamspy._algebra.expression as expression
from gamspy.math.misc import MathOp

if TYPE_CHECKING:
    from gamspy._algebra.expression import Expression
    from gamspy._symbols.symbol import Symbol




def binomial(n: int | float | Symbol, k: int | float | Symbol) -> Expression:
    """
    (Generalized) Binomial coefficient for n > -1, -1 < k < n + 1

    Parameters
    ----------
    n : int | float | Symbol
    k : int | float | Symbol

    Returns
    -------
    Expression
    """
    if isinstance(n, (int, float)) and isinstance(k, (int, float)):
        return expression.Expression(None, MathOp("binomial", (n, k)), None)

    return expression.Expression(None, MathOp("binomial", (n, k)), None)





def centropy(
    x: int | float | Symbol,
    y: int | float | Symbol,
    z: float = 1e-20,
) -> Expression:
    """
    Cross-entropy. x . ln((x + z) / (y + z)

    Parameters
    ----------
    x : float | Symbol
    y : float | Symbol
    z : float, optional

    Returns
    -------
    Expression

    Raises
    ------
    ValueError
        if z is smaller than 0
    """
    if z < 0:
        raise ValueError("z must be greater than or equal to 0")

    return expression.Expression(None, MathOp("centropy", (x, y, z)), None)





def uniform(
    lower_bound: float | Expression,
    upper_bound: float | Expression,
) -> Expression:
    """
    Generates a random number from the uniform distribution between
    lower_bound and higher_bound

    Parameters
    ----------
    lower_bound : float
    upper_bound : float

    Returns
    -------
    Expression
    """
    return expression.Expression(
        None, MathOp("uniform", (lower_bound, upper_bound)), None
    )





def uniformInt(
    lower_bound: int | float, upper_bound: int | float
) -> Expression:
    """
    Generates an integer random number from the discrete uniform distribution
    whose outcomes are the integers between lower_bound and higher_bound.

    Parameters
    ----------
    lower_bound : int | float
    upper_bound : int | float
    Returns
    -------
    Expression
    """
    return expression.Expression(
        None,
        MathOp("uniformInt", (lower_bound, upper_bound)),
        None,
    )





def normal(mean: int | float, dev: int | float) -> Expression:
    """
    Generate a random number from the normal distribution with mean `mean`
    and `standard deviation` dev.

    Parameters
    ----------
    mean : int | float
    dev : int | float

    Returns
    -------
    Expression
    """
    return expression.Expression(None, MathOp("normal", (mean, dev)), None)