[Python-checkins] python/dist/src/Lib timeit.py,1.4,1.5

[gvanrossum@users.sourceforge.net]

Update of /cvsroot/python/python/dist/src/Lib
In directory sc8-pr-cvs1:/tmp/cvs-serv22880

Modified Files:
	timeit.py 
Log Message:
Add a note explaining why you shouldn't try to compute mean and
standard deviation.  Also add an XXX comment wondering if we should
refrain from using itertools.repeat().


Index: timeit.py
===================================================================
RCS file: /cvsroot/python/python/dist/src/Lib/timeit.py,v
retrieving revision 1.4
retrieving revision 1.5
diff -C2 -d -r1.4 -r1.5
*** timeit.py	6 Mar 2003 13:09:09 -0000	1.4
--- timeit.py	6 Mar 2003 16:11:17 -0000	1.5
***************
*** 52,55 ****
--- 52,58 ----
  # instructions.
  
+ # XXX Maybe for convenience of comparing with previous Python versions,
+ # itertools.repeat() should not be used at all?
+ 
  import sys
  import math
***************
*** 134,137 ****
--- 137,151 ----
          the second argument specifies the timer argument, defaulting
          to one million.
+ 
+         Note: it's tempting to calculate mean and standard deviation
+         from the result vector and report these.  However, this is not
+         very useful.  In a typical case, the lowest value gives a
+         lower bound for how fast your machine can run the given code
+         snippet; higher values in the result vector are typically not
+         caused by variability in Python's speed, but by other
+         processes interfering with your timing accuracy.  So the min()
+         of the result is probably the only number you should be
+         interested in.  After that, you should look at the entire
+         vector and apply common sense rather than statistics.
          """
          r = []