ginibets

import random

#intuitive reason is that 0.95*1.05 = 0.99749, so that's the odd, if you play always 5% on a fair coin,
#the best strategy then is to play less % as possible, and this happens for the rich,
#that match the % of the poor, that % beeing for him less (in %)
#https://www.scientificamerican.com/article/is-inequality-inevitable/

def generate_oligarchy(time):
    def choose_ppl():
        result = -1
        while result <= 0:
            pick = random.randint(0, len(ppl)-1)
            result = ppl[pick]
        return pick

    ppl = [100.]*1000 #at the beginning there are 1000 persons with 100 coins
    for t in range(time):
        a = choose_ppl()
        b = choose_ppl()
        bet = min(a, b)*.05 #the poorer bet 5% on a coin flip, the richer match the bet
        if random.random() >= 0.5:
            ppl[a] += bet
            ppl[b] -= bet
        else:
            ppl[a] -= bet
            ppl[b] += bet

    ppl.sort()
    ppl = ppl[::-1]
    print time
    return ppl

x = 0
for t in range(1,7):
    ppl = generate_oligarchy(10**t)
    open('gini_'+str(x), 'w').write('\n'.join(map(str, ppl)))

print '''gnuplot -p -e "set yrange [0:1000]; plot 'gini_1' w l; replot 'gini_2' w l; replot 'gini_3' w l; replot 'gini_4' w l; replot 'gini_5' w l; replot 'gini_6' w l; replot 'gini_7' w l; replot 'gini_8' w l; set term png size 900,700; set output 'gini.png'; replot; pause mouse close"'''