# This code is part of the Biopython distribution and governed by its
# license.  Please see the LICENSE file that should have been included
# as part of this package.

"""Tests for lowess module."""

try:
    from numpy import array, median
except ImportError:
    from Bio import MissingExternalDependencyError

    raise MissingExternalDependencyError(
        "Install NumPy if you want to use Bio.Statistics.lowess."
    ) from None

from Bio.Statistics.lowess import lowess
import unittest


class test_lowess(unittest.TestCase):
    def test_Precomputed(self):
        x = array([0.0, 1.0, 2.0, 3.0, 5.0, 9.0, 11.0])
        y = x ** 2
        # Precalculated smooth output
        ys = array(
            [
                -2.96219015,
                1.72680044,
                6.58686813,
                11.62986671,
                28.18598762,
                86.85271581,
                116.83893423,
            ]
        )
        # Smooth output calculated by the lowess function
        output = lowess(x, y, f=2.0 / 3.0, iter=3)
        for precomputed, calculated in zip(ys, output):
            self.assertAlmostEqual(precomputed, calculated, places=4)


if __name__ == "__main__":
    runner = unittest.TextTestRunner(verbosity=2)
    unittest.main(testRunner=runner)