Merge pull request #13837 from mattip/seedsequence2

MAINT, BUG: fixes from seedsequence

1 files changed, 23 insertions, 2 deletions

diff --git a/doc/source/reference/random/bit_generators/index.rst b/doc/source/reference/random/bit_generators/index.rst
index 9907988fa..4540f60d9 100644
--- a/doc/source/reference/random/bit_generators/index.rst
+++ b/doc/source/reference/random/bit_generators/index.rst
@@ -12,6 +12,27 @@ setting the state, jumping or advancing the state, and for accessing
 low-level wrappers for consumption by code that can efficiently
 access the functions provided, e.g., `numba <https://numba.pydata.org>`_.
 
+Supported BitGenerators
+=======================
+
+The included BitGenerators are:
+
+* MT19937 - The standard Python BitGenerator. Adds a `~mt19937.MT19937.jumped`
+  function that returns a new generator with state as-if ``2**128`` draws have
+  been made.
+* PCG-64 - Fast generator that support many parallel streams and
+  can be advanced by an arbitrary amount. See the documentation for
+  :meth:`~.PCG64.advance`. PCG-64 has a period of
+  :math:`2^{128}`. See the `PCG author's page`_ for more details about
+  this class of PRNG.
+* Philox - a counter-based generator capable of being advanced an
+  arbitrary number of steps or generating independent streams. See the
+  `Random123`_ page for more details about this class of bit generators.
+
+.. _`PCG author's page`: http://www.pcg-random.org/
+.. _`Random123`: https://www.deshawresearch.com/resources_random123.html
+
+
 .. toctree::
    :maxdepth: 1
 
@@ -33,8 +54,8 @@ generate BitGenerators that are correlated or overlap within a few samples.
 
 NumPy uses a `SeedSequence` class to mix the seed in a reproducible way that
 introduces the necessary entropy to produce independent and largely non-
-overlapping streams. Small seeds may still be unable to reach all possible
-initialization states, which can cause biases among an ensemble of small-seed
+overlapping streams. Small seeds are unable to fill the complete range of
+initializaiton states, and lead to biases among an ensemble of small-seed
 runs. For many cases, that doesn't matter. If you just want to hold things in
 place while you debug something, biases aren't a concern.  For actual
 simulations whose results you care about, let ``SeedSequence(None)`` do its