#!/usr/bin/env python
from unittest import TestCase, main

from cogent3.maths.stats.information_criteria import aic, bic


__author__ = "Gavin Huttley"
__copyright__ = "Copyright 2007-2020, The Cogent Project"
__credits__ = ["Gavin Huttley"]
__license__ = "BSD-3"
__version__ = "2020.12.21a"
__maintainer__ = "Gavin Huttley"
__email__ = "gavin.huttley@anu.edu.au"
__status__ = "Production"

from numpy.testing import assert_allclose


class InformationCriteria(TestCase):
    """Tests calculation of AIC and BIC measures."""

    def test_aic(self):
        """correctly compute AIC from Burnham & Anderson 2002, p102"""
        assert_allclose(aic(-9.7039, 4), 27.4078)

    def test_aic_corrected(self):
        """correctly compute AIC corrected for small sample size"""
        # from Burnham & Anderson 2002, p102
        assert_allclose(aic(-9.7039, 4, sample_size=13), 32.4078)

    def test_bic(self):
        """correctly compute BIC"""
        # against hand calculated
        assert_allclose(bic(-9.7039, 4, 13), 29.6675974298)


if __name__ == "__main__":
    main()
