Tinyarray
=========

Tinyarrays are similar to NumPy arrays, but optimized for small sizes.  Common
operations on very small arrays are up to 35 times faster than with NumPy, and 3
times less memory is used to store them.  Tinyarrays are useful if you need many
small arrays of numbers, and cannot combine them into a few large ones.  (The
resulting code is still much slower than C, but it may now be fast enough.)

Unlike Python's built-in tuples, Tinyarrays support mathematical operations like
element-wise addition and matrix multiplication.  Unlike Numpy arrays,
Tinyarrays can be used as dictionary keys because they are hashable and
immutable.

The module's interface is a subset of that of NumPy and thus should be familiar
to many.  Whenever an operation is missing from Tinyarray, NumPy functions can
be used directly with Tinyarrays.


Tinyarray is licensed under the "simplified BSD License".  See `<LICENSE>`_.

Website: http://git.kwant-project.org/tinyarray/about/


Source code
-----------

Source tarballs are available at http://downloads.kwant-project.org/tinyarray/

Clone the Git repository with ::

    git clone http://git.kwant-project.org/tinyarray


Installation
------------

You can build from source with the usual ``python setup.py install``.  ``pip
install tinyarray`` should also work.

Prepared packages also exist:

* Windows

  Use `Christoph Gohlke's installer
  <http://www.lfd.uci.edu/~gohlke/pythonlibs/#tinyarray>`_.

* Ubuntu and derivatives ::

      sudo apt-add-repository ppa:kwant-project/ppa
      sudo apt-get update
      sudo apt-get install python-tinyarray

* Debian and derivatives

  1. Add the following lines to ``/etc/apt/sources.list``::

         deb http://downloads.kwant-project.org/debian/ stable main
         deb-src http://downloads.kwant-project.org/debian/ stable main

  2. (Optional) Add the OpenPGP key used to sign the repositories by executing::

         sudo apt-key adv --keyserver pgp.mit.edu --recv-key C3F147F5980F3535

  3. Update the package data, and install::

         sudo apt-get update
         sudo apt-get install python-tinyarray

* Mac OS X

  Follow the `instructions for installing "Kwant"
  <http://kwant-project.org/install#mac-os-x>`_ but install
  ``py27-tinyarray`` instead of ``py27-kwant`` etc.


Usage example
-------------

The following example shows that in simple cases Tinyarray works just as
NumPy. ::

    from math import sin, cos, sqrt
    import tinyarray as ta

    # Make a vector.
    v = ta.array([1.0, 2.0, 3.0])

    # Make a rotation matrix.
    alpha = 0.77
    c, s = cos(alpha), sin(alpha)
    rot_z = ta.array([[c, -s, 0],
                      [s,  c, 0],
                      [0,  0, 1]])

    # Rotate the vector, normalize, and print it.
    v = ta.dot(rot_z, v)
    v /= sqrt(ta.dot(v, v))
    print v


Documentation
-------------

The module's interface is a basic subset of NumPy and hence should be familiar
to many Python programmers.  All functions are simplified versions of their
NumPy counterparts.  The module's docstring serves as main documentation.  To
see it, run in Python::

    import tinyarray as ta
    help(ta)

Or in the system shell::

    pydoc tinyarray


Authors
-------

The principal developer of Tinyarray is Christoph Groth (SPSMS-INAC-CEA
Grenoble).  His contributions are part of his work at `CEA <http://cea.fr/>`_,
the French Commissariat à l'énergie atomique et aux énergies alternatives.

The author can be reached at christoph.groth@cea.fr.

Other people that have contributed to Tinyarray include

* Michael Wimmer (Leiden University)
* Joseph Weston (SPSMS-INAC-CEA Grenoble)
