# MetaBlender2

 Author Sean Submission date 2016-02-16 17:38:25.530278 Rating 6367 Matches played 334 Win rate 68.26

Use rpsrunner.py to play unranked matches on your computer.

## Source code:

``````if input == "":

import collections
import random

def random_index(ps):
t = sum(ps)
r = random.uniform(0, t)
x = 0
for i, p in enumerate(ps):
x += p
if r <= x:
break
return i

class MarkovTree:
def __init__(self):
self.counts = [0 for _ in xrange(3)]
self.children = None

def update(self, h, i):
stop = False
for d, k in enumerate(h):
try:
for j in xrange(3):
self.counts[j] += 2 * i[j]
except TypeError:
self.counts[i] += 2
if stop or d >= 16:
return
if self.children is None:
self.children = [None for _ in xrange(3)]
if self.children[k] is None:
self.children[k] = MarkovTree()
stop = True
self = self.children[k]

def predict(self, h):
n0 = [1, 1, 1]
for d, k in enumerate(h):
for i, x in enumerate(self.counts):
n0[i] += x
if self.children is None:
break
child = self.children[k]
if child is None:
break
self = child
return n0

R, P, S = 0, 1, 2
index = {"R": R, "P": P, "S": S}
beat = (P, S, R)
name = ("R", "P", "S")
strategies = [(R, P, S),
(P, S, R),
(S, R, P)]
tree = MarkovTree()
meta_tree = MarkovTree()

history = collections.deque([])

else:

i = index[input]
j = index[output]

tree.update(history, i)
probs = [0 for _ in xrange(3)]
f = 1.0 / sum(counts)
for k, x in enumerate(strategies):
for l, n in enumerate(counts):
if x[l] == i:
probs[k] = n * f
break
meta_tree.update(history, probs)
history.appendleft(i)
history.appendleft(j)

counts = tree.predict(history)
meta_counts = meta_tree.predict(history)
hypotheses = [None for _ in xrange(50)]
for i, _ in enumerate(hypotheses):
x = random_index(counts)
m = random_index(meta_counts)
hypotheses[i] = strategies[m][x]
scores = [0, 0, 0]
for i, _ in enumerate(scores):
for h in hypotheses:
if i == beat[h]:
scores[i] += 1
elif h == beat[i]:
scores[i] -= 1
best = max(scores)
prediction = random.choice([i for i in xrange(3) if scores[i] == best])
output = name[prediction]``````