Source code for gammapy.utils.distributions.utils

# Licensed under a 3-clause BSD style license - see LICENSE.rst
"""Helper functions to work with distributions."""
from scipy.integrate import quad
from ...utils.random import get_random_state
from ...utils.distributions import GeneralRandom

__all__ = ["normalize", "density", "draw", "pdf"]


[docs]def normalize(func, x_min, x_max): """Normalize a 1D function over a given range.""" def f(x): return func(x) / quad(func, x_min, x_max)[0] return f
[docs]def pdf(func): """One-dimensional PDF of a given radial surface density.""" def f(x): return x * func(x) return f
[docs]def density(func): """Radial surface density of a given one dimensional PDF.""" def f(x): return func(x) / x return f
[docs]def draw(low, high, size, dist, random_state="random-seed", *args, **kwargs): """Allows drawing of random numbers from any distribution.""" random_state = get_random_state(random_state) def f(x): return dist(x, *args, **kwargs) d = GeneralRandom(f, low, high) return d.draw(size, random_state=random_state)