Python c4 Examples

Example #1

def test_cv_unbiased_std():
    for i in range(10):
        values = [random.normalvariate(0, 1) for i in range(10)]
        cv = ContinuousValue()
        cv.update_batch(values)
        assert (cv.unbiased_std() -
                ((len(values) * utils.std(values) /
                  (len(values) - 1)) / utils.c4(len(values))) < 0.00000000001)

Example #2

File: test_utils.py Project: cmaclell/concept_formation

def test_cv_unbiased_std():
    for i in range(10):
        values = [random.normalvariate(0, 1) for i in range(10)]
        cv = ContinuousValue()
        cv.update_batch(values)
        assert (cv.unbiased_std() -
                ((len(values) * utils.std(values) / (len(values) - 1)) /
                 utils.c4(len(values))) < 0.00000000001)

Example #3

File: cobweb3.py Project: Krysia/concept_formation

    def unbiased_std(self):
        """Returns an unbiased estimate of the std 

        This implementation uses Bessel's correction and Cochran's theorem: 
        `<https://en.wikipedia.org/wiki/Unbiased_estimation_of_standard_deviation#Bias_correction>`_

        :return: an unbiased estimate of the std
        :rtype: float

        .. seealso:: :meth:`concept_formation.utils.c4`
        """
        if self.num < 2:
            return 0.0
        return sqrt(self.meanSq / (self.num - 1)) / c4(self.num)

Example #4

File: continuous_value.py Project: anybass/HONto

    def unbiased_std(self):
        """
        Returns an unbiased estimate of the std, but for n < 2 the std is
        estimated to be 0.0.

        This implementation uses Bessel's correction and Cochran's theorem: 
        `<https://en.wikipedia.org/wiki/Unbiased_estimation_of_standard_deviation#Bias_correction>`_

        :return: an unbiased estimate of the std
        :rtype: float

        .. seealso:: :meth:`concept_formation.utils.c4`
        """
        if self.num < 2:
            return 0.0
        return sqrt(self.meanSq / (self.num - 1)) / c4(self.num)

Example #5

def test_c4():
    with pytest.raises(ValueError):
        utils.c4(1)

Example #6

File: test_utils.py Project: cmaclell/concept_formation

def test_c4():
    with pytest.raises(ValueError):
        utils.c4(1)