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Diffstat (limited to 'Doc/whatsnew/3.2.rst')
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diff --git a/Doc/whatsnew/3.2.rst b/Doc/whatsnew/3.2.rst index 1693f7c..4cbb028 100644 --- a/Doc/whatsnew/3.2.rst +++ b/Doc/whatsnew/3.2.rst @@ -972,6 +972,45 @@ datetime and time (Contributed by Alexander Belopolsky and Victor Stinner.) +math +---- + +The :mod:`math` module has been updated with five new functions inspired by the +C99 standard. + +The :func:`~math.isfinite` function provides a reliable and fast way to detect +special values. It returns *True* for regular numbers and *False* for *Nan* or +*Infinity*: + +>>> [isfinite(x) for x in (123, 4.56, float('Nan'), float('Inf'))] +[True, True, False, False] + +The :func:`~math.expm1` function computes ``e**x-1`` for small values of *x* +without incuring the loss of precision that usually accompanies the subtraction +of nearly equal quantities: + +>>> expm1(0.013671875) # more accurate way to compute e**x-1 for a small x +0.013765762467652909 + +The :func:`~math.erf` function computes a probability integral of `Gaussian +error function <http://en.wikipedia.org/wiki/Error_function>`_: + +>>> erf(1.0/sqrt(2.0)) # portion of normal distribution within 1 standard deviation +0.682689492137086 + +:func:`~math.gamma` is a continuous extension of the factorial function. See +http://en.wikipedia.org/wiki/Gamma_function for details. Because the function +is related to factorials, it grows large even for small values of *x*, so there +is also a :func:`~math.lgamma` for computing the natural logarithm of the gamma +function: + +>>> gamma(7.0) # six factorial +720.0 +>>> lgamma(801.0) # log(800 factorial) +4551.950730698041 + +(Contributed by Mark Dickinson.) + abc --- |