python 中的轻微舍入错误

Question

我正在根据自动评分器检查我的代码，我遇到了这个。

这是我所有的代码：

def zeros(n, m = 0):
    if m == 0:
        m = n
    """creates matrix[n][m] of zeros """ 
    mat = [[0 for col in range(m)] for row in range (n)];
    return mat

def get_binomial_factors(sigma, rf, div, h):
    '''binomial factors given sigma, rf, div, h'''
    u = math.exp((rf-div)*h+sigma*math.sqrt(h))
    d = math.exp((rf-div)*h-sigma*math.sqrt(h))
    ans = (u, d)
    return ans
    
def get_risk_neutral_probability(sigma, rf, div, h):
    '''risk neutral probability given sigma, rf, div, h'''
    tuple = get_binomial_factors(sigma, rf, div, h)
    u = tuple[0]
    d = tuple[1]
    p = (math.exp((rf - div)*h)-d)/(u-d)
    return p 

def build_euro_call_value_tree(s, x, sigma, rf, div, T, n):
    '''Builds a binomial call option pricing tree using the underlying stock tree'''
    h = T/n
    tuple = get_binomial_factors(sigma, rf, div, h)
    p = get_risk_neutral_probability(sigma, rf, div, h)
    u = tuple[0]
    d = tuple[1]
    stock_tree = build_binomial_stock_price_tree(s, sigma, rf, div, T, n)
    option_tree = zeros(n+1)
    for i in range(n, -1, -1):
        for j in range(i + 1):
            if i == n:
                option_tree[j][i] = max(0, stock_tree[j][i] - x)
            else:
                option_tree[j][i] = (1 / (1 + rf*h)) * (p * option_tree[j][i+1] + (1 - p) * option_tree[j+1][i+1])
    
    return option_tree

我尝试包括 Decimal 并在那里做一些事情，但它并没有真正解决它