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LiberPrayground/LP/Probability.py
2021-02-20 12:59:29 +01:00

63 lines
1.9 KiB
Python
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#!/usr/bin/env python3
# -*- coding: UTF-8 -*-
from NGrams import NGrams
from Alphabet import RUNES
def normalized_probability(int_prob):
total = sum(int_prob)
return [x / total for x in int_prob] # math.log(x / total, 10)
PROB_INT = [0] * 29
for k, v in NGrams.load(1, '').items(): # '-no-e', '-solved'
PROB_INT[RUNES.index(k)] = v
PROB_NORM = normalized_probability(PROB_INT)
# Target IoC. peace and war: 1.77368517 solved: 1.78021503, no e: 1.82715300
N_total = (sum(PROB_INT) * (sum(PROB_INT) - 1)) / 29
TARGET_IOC = sum(x * (x - 1) for x in PROB_INT) / N_total
# TARGET_IOC = 1.78
#########################################
# Probability : Count runes and do simple frequency analysis
#########################################
class Probability(object):
def __init__(self, numstream):
self.prob = [0] * 29
for r in numstream:
self.prob[r] += 1
self.N = sum(self.prob)
def IC(self):
X = sum(x * (x - 1) for x in self.prob)
return X / ((self.N * (self.N - 1)) / 29)
def IC_norm(self, target_ioc=TARGET_IOC):
return abs(self.IC() - target_ioc)
def similarity(self):
probs = normalized_probability(self.prob)
return sum((x - y) ** 2 for x, y in zip(PROB_NORM, probs))
@staticmethod
def IC_w_keylen(nums, keylen):
val = sum(Probability(nums[x::keylen]).IC() for x in range(keylen))
return val / keylen
@staticmethod
def target_diff(nums, keylen, target_ioc=TARGET_IOC):
val = sum(abs(Probability(nums[x::keylen]).IC() - target_ioc)
for x in range(keylen))
return 1 - (val / keylen)
@staticmethod
def parts_high(parts, keylen):
return sum(Probability(x).IC() for x in parts) / keylen
@staticmethod
def parts_norm(parts, keylen, target_ioc=TARGET_IOC):
val = sum(abs(Probability(x).IC() - target_ioc) for x in parts)
return 1 - (val / keylen)