如何让python计数器在有多个if语句的函数中工作？

Question

我有一个大的函数，用来模拟一个反应系统的时间。我在函数中添加了一个 leap_couner 来计算时间上的步数。

def gillespie_tau_leaping(propensity_calc, popul_num, LHS, stoch_rate, popul_num_all, tao_all, rxn_vector, delta_t, tao, epsi):
    t = simulation_timer()
    t.start()
    while tao < tmax:
        propensity = propensity_calc(LHS, popul_num, stoch_rate)    
        a0 = (sum(propensity))  
        if a0 == 0.0:  
            print("Propensity sum is zero end execution")   
            break   
        if popul_num.any() < 0:       
            print("Molecules numbers below zero end execution")
            break
        lam = (propensity_calc(LHS, popul_num, stoch_rate)*delta_t)    
        rxn_vector = np.random.poisson(lam) 
        if tao + delta_t > tmax:
            break    
        tao += delta_t 
        leap_counter = 0
        if delta_t >= 1 / a0:
            for j in range(len(rxn_vector)):  
                state_change_lambda = np.squeeze(np.asarray(state_change_array[j])*rxn_vector[j]) 
                popul_num = popul_num + state_change_lambda   
                leap_counter += 1    # Not working!
            popul_num_all.append(popul_num)
            tao_all.append(tao) 
            leap_counter += 1  
        else:   # else execute the ssa because it's faster
            next_t = np.random.exponential(1/a0)
            rxn_probability = propensity / a0   
            num_rxn = np.arange(rxn_probability.size)       
            if tao + next_t > tmax:      
                tao = tmax
                break
            j = stats.rv_discrete(values=(num_rxn, rxn_probability)).rvs() 
            tao = tao + next_t
            popul_num = popul_num + np.squeeze(np.asarray(state_change_array[j]))  
            popul_num_all.append(popul_num)   
            tao_all.append(tao)    
    print("Molecule numbers:\n", popul_num)
    print("Time of final simulation:\n", tao)
    print("leap counter:\n", leap_counter)
    t.stop()
    return popul_num_all.append(popul_num), tao_all.append(tao), popul_num

这就是完整的功能，下面是计数器的具体位。

if tao + delta_t > tmax:
    break    
tao += delta_t 
leap_counter = 0
if delta_t >= 1 / a0:
    for j in range(len(rxn_vector)):  
        state_change_lambda = np.squeeze(np.asarray(state_change_array[j])*rxn_vector[j]) 
        popul_num = popul_num + state_change_lambda   
        leap_counter += 1    # Not working!
    popul_num_all.append(popul_num)
    tao_all.append(tao) 

tao 是当前的时间。delta_t 是增加的价值和 tmax 是最大的模拟时间。如果 tao + delta_t 小于 tmax 那么当前时间就会以 delta_t.

然后我用 delta_t 来决定我使用哪种闰土法。如果我使用第一种闰土法 if delta_t >= 1/a0 然后，我想计算每次递增的时间（由 delta_t)，并返回增量的数量 leap_counter

只不过我现在的计数器有问题，它只是返回零，我不知道怎么改才能让它正常工作。

干杯

Answer 1

你需要移动这一行

leap_counter = 0

在while循环外。目前它被设置为 0 每次迭代