From 2606be9a5f2cb0d31ed78e187759988fa2592d41 Mon Sep 17 00:00:00 2001
From: Katharina Eggensperger <eggenspk@informatik.uni-freiburg.de>
Date: Fri, 24 Feb 2017 10:52:45 +0100
Subject: [PATCH] ADD helper methods to get/create RandomState - work on #2

---
 hpolib/util/rng_helper.py | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)
 create mode 100644 hpolib/util/rng_helper.py

diff --git a/hpolib/util/rng_helper.py b/hpolib/util/rng_helper.py
new file mode 100644
index 0000000..294454b
--- /dev/null
+++ b/hpolib/util/rng_helper.py
@@ -0,0 +1,36 @@
+import numpy as np
+
+
+def get_rng(rng=None, self_rng=None):
+    """ helper function to obtain RandomState.
+    returns RandomState created from rng
+    if rng is None returns self_rng if RandomState
+    if self_rng is None initializes RandomState at random
+
+    :param rng: int or RandomState
+    :param self_rng: RandomState
+    :return: RandomState
+    """
+
+    if rng is not None:
+        return create_rng(rng)
+    elif rng is None and self_rng is not None:
+        return create_rng(self_rng)
+    else:
+        return np.random.RandomState()
+
+
+def create_rng(rng):
+    """ helper to create rng from RandomState or int
+    :param rng: int or RandomState
+    :return: RandomState
+    """
+    if rng is None:
+        return np.random.RandomState()
+    elif type(rng) == np.random.RandomState:
+        return rng
+    elif int(rng) == rng:
+        return np.random.RandomState(rng)
+    else:
+        raise ValueError("%s is neither a number nor a RandomState. "
+                         "Initializing RandomState failed")
\ No newline at end of file