DOC: Add documentation to main module

Add explanatio fo module intent to module init

Author: bashtage

randomstate/__init__.py

@@ -1,3 +1,62 @@
+"""
+randomstate contains implements NumPy-like RandomState objects with an
+enhanced feature set.
+
+This modules includes a number of alternative random number generators
+in addition to the MT19937 that is included in NumPy. The RNGs include:
+
+-  `MT19937 <https://github.com/numpy/numpy/blob/master/numpy/random/mtrand/>`__,
+   the NumPy rng
+-  `dSFMT <http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/SFMT/>`__ a
+   SSE2-aware version of the MT19937 generator that is especially fast
+   at generating doubles
+-  `SFMT <http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/SFMT/>`__ a
+   SSE2-aware version of the MT19937 generator that is optimized for
+   integer values
+-  `xorshift128+ <http://xorshift.di.unimi.it/>`__,
+   `xoroshiro128+ <http://xoroshiro.di.unimi.it/>`__ and
+   `xorshift1024\* <http://xorshift.di.unimi.it/>`__
+-  `PCG32 <http://www.pcg-random.org/>`__ and
+   `PCG64 <http:w//www.pcg-random.org/>`__
+-  `MRG32K3A <http://simul.iro.umontreal.ca/rng>`__
+-  A multiplicative lagged fibonacci generator (LFG(63, 1279, 861, \*))
+
+Help is available at `on github <https://bashtage.github.io/ng-numpy-randomstate>`_.
+
+New Features
+------------
+
+-  ``standard_normal``, ``normal``, ``randn`` and
+   ``multivariate_normal`` all support an additional ``method`` keyword
+   argument which can be ``bm`` or ``zig`` where ``bm`` corresponds to
+   the current method using the Box-Muller transformation and ``zig``
+   uses the much faster (100%+) Ziggurat method.
+-  ``standard_exponential`` and ``standard_gamma`` both support an
+   additional ``method`` keyword argument which can be ``inv`` or
+   ``zig`` where ``inv`` corresponds to the current method using the
+   inverse CDF and ``zig`` uses the much faster (100%+) Ziggurat method.
+-  Core random number generators can produce either single precision
+   (``np.float32``) or double precision (``np.float64``, the default)
+   using an the optional keyword argument ``dtype``
+-  Core random number generators can fill existing arrays using the
+   ``out`` keyword argument
+
+New Functions
+-------------
+
+-  ``random_entropy`` - Read from the system entropy provider, which is
+   commonly used in cryptographic applications
+-  ``random_raw`` - Direct access to the values produced by the
+   underlying PRNG. The range of the values returned depends on the
+   specifics of the PRNG implementation.
+-  ``random_uintegers`` - unsigned integers, either 32-
+   (``[0, 2**32-1]``) or 64-bit (``[0, 2**64-1]``)
+-  ``jump`` - Jumps RNGs that support it. ``jump`` moves the state a
+   great distance. *Only available if supported by the RNG.*
+-  ``advance`` - Advanced the core RNG 'as-if' a number of draws were
+   made, without actually drawing the numbers. *Only available if
+   supported by the RNG.*
+"""
 from __future__ import division, absolute_import, print_function
 
 from randomstate.prng.mt19937 import *