Germen Tank Problem

tank.py

from collections import Counter


class Tank():
    def __init__(self, value):
        self.tab = dict(Counter(value))

    def mult(self, x, factor):
        self.tab[x] = self.tab[x] * factor

    def likelihood(self, observe, hypo):
        if hypo < observe:
            return 0
        else:
            return 1.0 / hypo

    def normalize(self, fraction=1.0):
        total = sum(self.tab.values())
        factor = float(fraction) / total
        for x in self.tab:
            self.tab[x] *= factor

        return sum(self.tab)

    def update(self, observe):
        for hypo in self.tab.keys():
            like = self.likelihood(observe, hypo)
            self.mult(hypo, like)
        return self.normalize()

    def print(self):
        for val, prob in sorted(self.tab.items()):
            print(val, prob)

    def confidence(self, target=99):
        target = 1 - 99 / 100.0
        sumup = 0
        for key in reversed(sorted(self.tab.keys())):
            sumup += self.tab[key]
            if sumup > target:
                print('confidence = %s' % key)
                break


def main():
    suite = Tank([500, 1000, 1500, 2000, 3000])
    for roll in [4, 180, 75, 1007, 1003, 1500]:
        suite.update(roll)
    print('After more obs')
    suite.print()
    # suite.confidence()


if __name__ == '__main__':
    main()