Martingale.py

# -*- coding: utf-8 -*-
"""
Created on Mon Jan 25 15:08:53 2021

Simulates gambling with the "Martingale" strategy, where one doubles their bet after each loss to recover all previous losses and their original bet.
Free money right? Simulate to see.

Parameters:
n_sims = number of times you want to simulate the play function
start_chips = number of chips you have
start_bet = your initial bet (will be doubled after each loss)
odds = [p q] where p is the number of ways to lose and q is the number of ways to win. 5:1 odds are represented with odds = [5,1].
house edge = percentage that the house takes off of the probability of winning for each bet
"""

import numpy as np

def play(start_chips, start_bet, odds, house_edge):
    chips = start_chips
    bet = start_bet
    count = 0
    while chips > bet:
        p = ( odds[1] / (odds[0] + odds[1]) ) * (1 - house_edge)
        if np.random.binomial(1, p):
            chips += odds[0] * ( bet / odds[1] )
            bet = start_bet
        else:
            chips -= bet
            bet *= 2
        winnings = chips - start_chips
        count += 1
        if chips > start_chips:
            outcome = "success"
            break
        else:
            outcome = "catastrophic failure"
    return winnings, count, outcome

def simulate(n_sims, start_chips, start_bet, odds, house_edge):
    n_wins = 0
    total_winnings = 0
    for i in range(n_sims):
        winnings, count, outcome = play(start_chips, start_bet, odds, house_edge)
        if winnings > 0:
            n_wins += 1
        total_winnings += winnings
    percent_wins = n_wins/n_sims
    print(percent_wins, total_winnings)

simulate(n_sims=1000, start_chips=1000, start_bet=20, odds=[50,1], house_edge=0) #