Cythonize random generators

A trivial cythonized version of the c++ random_generator class.
Useful to get the names of the generators from the python.

  new file:   pytriqs/random/*
  new file:   doc/reference/python/random/*

doc/reference/python/contents.rst

@@ -9,4 +9,5 @@ Python
    operators/operators
    lattice/lattice
    data_analysis/contents
+   random/random
 

doc/reference/python/operators/operators.rst

@@ -1,5 +1,6 @@
-.. _operators:
+.. module:: pytriqs.random 
 
+.. _operators:
 
 The Operator class
 ===================

doc/reference/python/random/random.py

@@ -0,0 +1,7 @@
+from pytriqs.random import *
+from pytriqs.plot.mpl_interface import *
+
+r = RandomGenerator("lagged_fibonacci607", 237489)
+l = []
+for i in range(10000): l += [r.rand(),]
+plt.hist(l, 30, normed=True);

doc/reference/python/random/random.rst

@@ -0,0 +1,48 @@
+.. index:: Random number generator
+
+.. module:: pytriqs.random
+
+.. _random_generator:
+
+Random generator class
+======================
+
+TRIQS has a simple random number generator class called ``RandomGenerator``. It is based on boost
+just like the C++ random generator provided by TRIQS.
+
+Usage
+-----
+
+The generator is constructed from a name and a seed::
+
+  from pytriqs.random import *
+  r = RandomGenerator("mt19937", 237849)
+
+A list of possible random generator names is obtained with::
+
+  print available_generator_names()
+
+Then you can either generate float number on the interval :math:`[0,1[` using
+the ``rand()`` method or integer numbers in the inverval :math:`[0,N-1]` using
+``int_rand(N)``::
+
+  print r.rand()
+  print r.int_rand(10)
+
+Example
+-------
+
+Here's a simple example showing how to use the generator.
+
+.. plot:: reference/python/random/random.py
+   :include-source:
+   :scale: 70
+
+
+Complete reference
+------------------
+
+.. autoclass:: pytriqs.random.RandomGenerator
+  :members:
+
+.. autofunction:: pytriqs.random.available_generator_names

pytriqs/random/CMakeLists.txt

@@ -0,0 +1,8 @@
+SET(PYTHON_SOURCES 
+  ${CMAKE_CURRENT_SOURCE_DIR}/__init__.py
+)
+
+install (FILES ${PYTHON_SOURCES} DESTINATION ${TRIQS_PYTHON_LIB_DEST}/random)
+
+# the c++ code
+cython_module(random random_generator random)

pytriqs/random/__init__.py

@@ -0,0 +1,5 @@
+
+from random_generator import RandomGenerator, available_generator_names
+
+__all__ = ['RandomGenerator','available_generator_names']
+

pytriqs/random/random_generator.pyx

@@ -0,0 +1,49 @@
+from dcomplex cimport * 
+from libcpp.string cimport string
+
+# The c++ random generator class
+# We wrap two members only
+cdef extern from "triqs/mc_tools/random_generator.hpp": 
+
+    cdef cppclass random_generator "triqs::mc_tools::random_generator":
+
+        random_generator(string, long) except +
+        double operator() () except +
+        int operator() (int) except +
+
+# This is the wrapping of the static member random_generator_names
+# It is a bit of a hack but there is no notion of ststic members in cython
+cdef extern from "triqs/mc_tools/random_generator.hpp" namespace "triqs::mc_tools::random_generator":
+
+    string random_generator_names(string) except +
+
+
+# The python RandomGenerator class
+cdef class RandomGenerator:
+
+  cdef random_generator * _c
+
+  def __init__(self, name, seed):
+    """This is a random number generator class based on boost.
+
+       :param name: (string) Name of the random number generator
+       :param seed: (int) Random number seed
+    """
+    self._c = new random_generator(name, seed)
+
+  def __dealloc__(self):
+    del self._c
+
+  def rand(self):
+    """Generate a float random number in [0,1["""
+    return self._c[0]()
+
+  def int_rand(self, N):
+    """Generate an integer random number in [0,N-1]"""
+    return self._c[0](N)
+
+# The list of generator names accessed through the static member
+def available_generator_names():
+  """Get a list of available random generator names"""
+  return random_generator_names(",").split(',')
+