import numba
import numpy as np


@numba.njit
def identity(x):
    """A no-op link function."""
    return x
@numba.njit
def _identity_inverse(x):
    return x
identity.inverse = _identity_inverse

@numba.njit
def logit(x):
    """A logit link function useful for going from probability units to log-odds units."""
    return np.log(x/(1-x))
@numba.njit
def _logit_inverse(x):
    return 1/(1+np.exp(-x))
logit.inverse = _logit_inverse
