MAINT: move rv_discrete and rv_continuous into the distribution infra…

…structure module and prune redundant imports

runtests.py

@@ -170,8 +170,8 @@ def main(argv):
         try:
             __import__(modname)
             test = sys.modules[modname].test
-        except (ImportError, KeyError, AttributeError):
-            print("Cannot run tests for %s" % modname)
+        except (ImportError, KeyError, AttributeError) as e:
+            print("Cannot run tests for %s (%s)" % (modname, e))
             sys.exit(2)
     elif args.tests:
         def fix_test_path(x):

scipy/stats/_constants.py

@@ -0,0 +1,24 @@
+"""
+Statistics-related constants.
+
+"""
+from __future__ import division, print_function, absolute_import
+
+import numpy as np
+
+
+# The smallest representable positive number such that 1.0 + _EPS != 1.0.
+_EPS = np.finfo(float).eps
+
+# The largest [in magnitude] usable floating value.
+_XMAX = np.finfo(float).machar.xmax
+
+# The smallest [in magnitude] usable floating value.
+_XMIN = np.finfo(float).machar.xmin
+
+# -special.psi(1)
+_EULER = 0.577215664901532860606512090082402431042
+
+# special.zeta(3, 1)  Apery's constant
+_ZETA3 = 1.202056903159594285399738161511449990765
+