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February 19, 2019 19:24
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averaging priors vs averaging posteriors
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from random import * | |
from math import * | |
def randomOpen(): | |
while True: | |
r = random() | |
if 0 < r: | |
return r | |
class Grid(object): | |
def __init__(self, EH=None, NEH=None, ENH=None, NENH=None): | |
if EH is None: | |
EH = randomOpen() | |
NEH = randomOpen() | |
ENH = randomOpen() | |
NENH = randomOpen() | |
s = EH+NEH+ENH+NENH | |
EH /= s | |
NEH /= s | |
ENH /= s | |
NENH /= s | |
self.EH = EH | |
self.NEH = NEH | |
self.ENH = ENH | |
self.NENH = NENH | |
def average(self, a): | |
EH=self.EH+a.EH | |
NEH=self.NEH+a.NEH | |
ENH=self.ENH+a.ENH | |
NENH=self.NENH+a.NENH | |
s = EH+NEH+ENH+NENH | |
return Grid(EH=EH/s,NEH=NEH/s,ENH=ENH/s,NENH=NENH/s) | |
def posteriorH(self): | |
return self.EH/(self.EH+self.ENH) | |
maxDelta = 0 | |
avgDelta = 0 | |
N = 100000 | |
for i in range(N): | |
g1 = Grid() | |
g2 = Grid() | |
p1 = g1.posteriorH() | |
p2 = g2.posteriorH() | |
p3 = g1.average(g2).posteriorH() | |
p4 = (p1+p2)/2 | |
delta = abs(p4-p3) | |
maxDelta = max(maxDelta,delta) | |
avgDelta += delta | |
avgDelta /= N | |
print(maxDelta,avgDelta) |
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