import ODESolver
import matplotlib.pyplot as plt
import numpy as np



class Region:
    def __init__(self,region,S0,I0,R0,D0):
        self.S0 = S0
        self.I0 = I0
        self.R0 = R0
        self.D0 = D0
        self.region = region



    def set_SIRD_values(self,u,t):

        self.S = u[:,0]
        self.I = u[:,1]
        self.R = u[:,2]
        self.D = u[:,3]
        self.t = t

    def plot(self,x_label):
        plt.plot(self.t,self.S,label="Susceptible",color="blue")
        plt.plot(self.t,self.I,color="yellow")
        plt.plot(self.t,self.R,color="red")
        plt.plot(self.t,self.D,color="green")

class ProblemSIRD:
    def __init__(self,alpha,beta,gamma):
        self.region = region
        if isinstance(alpha,(float,int)):
            self.alpha = lambda t: alpha 
        elif callable(alpha):
            self.alpha = alpha
        self.beta = beta
        self.gamma = gamma

    def set_initial_condition(self):
        self.initial_condition = [self.region.S0,self.region.I0,self.region.R0,self.region.D0]
    def get_population(self):
        return self.region.S0 + self.region.I0 + self.region.R0 + self.region.D0
    def solution(self,t):
        return self.region.set_SIRD_values() 
    def __call__(self,t):
        S,I,R,D = u
        return [-self.alpha * S * I,self.alpha * S * I - self.beta * I - self.gamma * I,self.beta * I,self.gamma * I]

class SolverSIRD:
    def __init__(self,problem,T,dt):
        self.problem = problem
        self.T = T
        self.dt = dt
        self.total_population = ProblemSIRD.get_population(problem)

    def terminate(self,U,t,time_step):
        tol = 1e-10
        msg = 'Error in numerical method'
        assert abs(sum(U[time_step]) - self.total_population()) < tol,msg

    def solve(self,method=RungeKutta4):
        solver = method(self.problem)
        problem.set_initial_condition()
        t = np.linspace(0,self.T,self.dt)
        u,t = solver.solve(t,self.terminate)
        self.problem.solution(u,t)

U0 = [7000.0,30.0,0.0,0.0]
initialP = 63

alpha = 6.5e-5
beta = 0.1/4
gamma = 0.9/4

bjorgvin = Region('Bjorgvin',U0[0],U0[1],U0[2],U0[3])
problem = ProblemSIRD(alpha,gamma,bjorgvin)

solver = SolverSIRD(problem,63,64)
solver.solve(method = ODESolver.RungeKutta4)
Region.plot(x_label = bjorgvin)
plt.legend()
plt.show()

错误：

第50行，在get_population中  返回self.region.S0 + self.region.I0 + self.region.R0 + self.region.D0

AttributeError：“浮动”对象没有属性“ S0”

这里可能有多个错误，但是如果您能帮助我解决这个问题，我将不胜感激。我在“ set_initial_condition”功能中遇到了同样的问题。为什么我不能使用Region类中的属性？