[Pybridge-commits] SF.net SVN: pybridge: [353] trunk/pybridge/pybridge/bridge/deck.py

[<umg...@us...>]

Revision: 353
          http://svn.sourceforge.net/pybridge/?rev=353&view=rev
Author:   umgangee
Date:     2007-02-21 11:09:09 -0800 (Wed, 21 Feb 2007)

Log Message:
-----------
In indexToDeal, make initial n = k-1 instead of 0, to eliminate a few unnecessary calls to comb.

Modified Paths:
--------------
    trunk/pybridge/pybridge/bridge/deck.py

Modified: trunk/pybridge/pybridge/bridge/deck.py
===================================================================
--- trunk/pybridge/pybridge/bridge/deck.py	2007-02-18 21:51:28 UTC (rev 352)
+++ trunk/pybridge/pybridge/bridge/deck.py	2007-02-21 19:09:09 UTC (rev 353)
@@ -141,9 +141,14 @@
             deal[seat] = []
             for k in range(13, 0, -1):
                 # Find the largest n such that comb(n, k) <= indexes[seat].
-                n = 0
+                n = k-1  # n < k implies comb(n, k) = 0
+
+                # comb(n+1, k) =
+                #   n-k = -1  => comb(n, k) * (n+1)
+                #   otherwise => (comb(n, k) * (n+1)) / (n+1 - k)
                 while comb(n+1, k) <= indexes[seat]:
                     n += 1
+
                 # Remove card index from indices, add card to hand.
                 indexes[seat] -= comb(n, k)
                 card = cardSeq[n]


This was sent by the SourceForge.net collaborative development platform, the world's largest Open Source development site.