From: Raymond Hettinger <python@rcn.com>
Date: Tue, 22 Mar 2011 22:55:51 +0000 (-0700)
Subject: Issue 10787: Document the probability density function for random.gammavariate.
X-Git-Tag: v3.2.1b1~231^2
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=a8e4d6eb6e386dc12fa586bd4a920546b505f17b;p=thirdparty%2FPython%2Fcpython.git

Issue 10787: Document the probability density function for random.gammavariate.
---

diff --git a/Lib/random.py b/Lib/random.py
index 592e4b899a17..49f5859b2bae 100644
--- a/Lib/random.py
+++ b/Lib/random.py
@@ -470,6 +470,12 @@ class Random(_random.Random):
 
         Conditions on the parameters are alpha > 0 and beta > 0.
 
+        The probability distribution function is:
+
+                    x ** (alpha - 1) * math.exp(-x / beta)
+          pdf(x) =  --------------------------------------
+                      math.gamma(alpha) * beta ** alpha
+
         """
 
         # alpha > 0, beta > 0, mean is alpha*beta, variance is alpha*beta**2