Simple LOS/Elo calculator

gistfile1.py

#!/usr/bin/python
import math

def los(n1, n0):
  pi = [1.0] * (n1 + 3)
  pi[0] = 0

  for j in xrange(n0 + 1, 0, -1):
    for i in xrange(0, n1 + 1):
      pi[i + 1] = (pi[i + 1] + pi[i]) * 0.5

  return pi[n1 + 1] * 100

def elo(win_ratio):
  return 400 * math.log10(win_ratio / (1 - win_ratio))

draws = 823
wins = 195
losses = 246
total = float(wins + draws + losses)
win_ratio = (wins + (draws / 2)) / total
loss_ratio = 1 - win_ratio
draw_ratio = draws / total
denom99 = 2.58 * math.sqrt((win_ratio * loss_ratio) / (total - 1))
denom95 = 1.96 * math.sqrt((win_ratio * loss_ratio) / (total - 1))
elo_win = elo(win_ratio)
print "ELO: %.2f +- 99%%: %.2f 95%%: %.2f" % ( elo_win, elo(win_ratio + denom99) - elo_win, elo(win_ratio + denom95) - elo_win )
print "LOS: %.2f%%" % ( los(wins, losses) )
print "Wins: %d Losses: %d Draws: %d Total: %d" % (wins, losses, draws, int(total))
#print "Win%%: %.2f +- 99%%: %.2f 95%%: %.2f" % ( win_ratio * 100, denom99 * 100, denom95 * 100 )