asic concepts
of numpy are available under the ``doc`` sub-module::

  >>> from numpy import doc
  >>> help(doc)
  ... # doctest: +SKIP

Available subpackages
---------------------
lib
    Basic functions used by several sub-packages.
random
    Core Random Tools
linalg
    Core Linear Algebra Tools
fft
    Core FFT routines
polynomial
    Polynomial tools
testing
    NumPy testing tools
distutils
    Enhancements to distutils with support for
    Fortran compilers support and more.

Utilities
---------
test
    Run numpy unittests
show_config
    Show numpy build configuration
matlib
    Make everything matrices.
__version__
    NumPy version string

Viewing documentation using IPython
-----------------------------------

Start IPython and import `numpy` usually under the alias ``np``: `import
numpy as np`.  Then, directly past or use the ``%cpaste`` magic to paste
examples into the shell.  To see which functions are available in `numpy`,
type ``np.<TAB>`` (where ``<TAB>`` refers to the TAB key), or use
``np.*cos*?<ENTER>`` (where ``<ENTER>`` refers to the ENTER key) to narrow
down the list.  To view the docstring for a function, use
``np.cos?<ENTER>`` (to view the docstring) and ``np.cos??<ENTER>`` (to view
the source code).

Copies vs. in-place operation
-----------------------------
Most of the functions in `numpy` return a copy of the array argument
(e.g., `np.sort`).  In-place versions of these functions are often
available as array methods, i.e. ``x = np.array([1,2,3]); x.sort()``.
Exceptions to this rule are documented.

