0.013765762467652909
The :func:`~math.erf` function computes a probability integral or `Gaussian
-error function <http://en.wikipedia.org/wiki/Error_function>`_:
+error function <http://en.wikipedia.org/wiki/Error_function>`_. The
+complementary error function, :func:`~math.erfc`, is ``1 - erf(x)``:
>>> erf(1.0/sqrt(2.0)) # portion of normal distribution within 1 standard deviation
0.682689492137086
+>>> erfc(1.0/sqrt(2.0)) # portion of normal distribution outside 1 standard deviation
+0.31731050786291404
+>>> erf(1.0/sqrt(2.0)) + erfc(1.0/sqrt(2.0))
+1.0
The :func:`~math.gamma` function is a continuous extension of the factorial
function. See http://en.wikipedia.org/wiki/Gamma_function for details. Because
(Work by Nick Coghlan, Dan Mahn, and Senthil Kumaran in :issue:`2987`,
:issue:`5468`, and :issue:`9873`.)
+turtledemo
+----------
+
+The demonstration code for the :mod:`turtle` module was moved from the *Demo*
+directory to main library. It includes over a dozen sample scripts with
+lively displays. Being on :attr:`sys.path`, it can now be run directly
+from the command-line::
+
+ $ python -m turtledemo
+
Multi-threading
===============
:pep:`385` for details.
To learn to use the new version control system, see the `tutorial by Joel
-Spolsky <http://hginit.com>`_ or the `guide to Mercurial workflows
+Spolsky <http://hginit.com>`_ or the `Guide to Mercurial Workflows
<http://mercurial.selenic.com/guide/>`_.