Add Doc about MRG31k3p

doc/library/sandbox/index.txt

@@ -16,6 +16,4 @@
     cuda/index
     linalg
     neighbours
-
-
-
+    rng_mrg

doc/library/sandbox/rng_mrg.txt

+.. _libdoc_rng_mrg:
+
+===================================================================
+:mod:`sandbox.rng_mrg` --  MRG random number generator
+===================================================================
+
+.. module:: sandbox.rng_mrg
+   :platform: Unix, Windows
+   :synopsis: MRG random number generator
+.. moduleauthor:: LISA
+
+API
+===
+
+.. automodule:: theano.sandbox.rng_mrg
+    :members:

doc/tutorial/examples.txt

@@ -450,6 +450,10 @@ Other Random Distributions
 
 There are :ref:`other distributions implemented <libdoc_tensor_raw_random>`. 
 
+Other Implementation
+--------------------
+
+Their is 2 other implementation based on :class:`CURAND <theano.sandbox.cuda.rng_curand>` and :ref:`MRG31k3p <libdoc_rng_mrg>`
 
 .. _logistic_regression: