График Модели Лотки-Вольтерры

import matplotlib.pyplot as plt
import numpy as np
 
def rk4(r, t, h):                    #edited; no need for input f
        """ Runge-Kutta 4 method """
        k1 = h*f(r, t)
        k2 = h*f(r+0.5*k1, t+0.5*h)
        k3 = h*f(r+0.5*k2, t+0.5*h)
        k4 = h*f(r+k3, t+h)
        return (k1 + 2*k2 + 2*k3 + k4)
 
def f(r, t):
        alpha = 1.0
        beta = 0.5
        gamma = 0.5
        sigma = 2.0
        x, y = r[0], r[1]
        fxd = x*(alpha - beta*y)
        fyd = -y*(gamma - sigma*x)
        return np.array([fxd, fyd], float)
 
h=0.001                               #edited
tpoints = np.arange(0, 30, h)         #edited
xpoints, ypoints  = [], []
r = np.array([2, 2], float)
for t in tpoints:
        xpoints.append(r[0])          #edited
        ypoints.append(r[1])          #edited
        r += rk4(r, t, h)             #edited; no need for input f
plt.plot(tpoints, xpoints)
plt.plot(tpoints, ypoints)
plt.xlabel("Time")
plt.ylabel("Population")
plt.title("Lotka-Volterra Model")
plt.savefig("Lotka_Volterra.png")
plt.show()

alpha = input()
        beta = input()
        gamma = input()
        sigma = input()

x = int(input())

x = float(input())

import matplotlib.pyplot as plt
import numpy as np
 
def rk4(r, t, h):                    #edited; no need for input f
        """ Runge-Kutta 4 method """
        k1 = h*f(r, t)
        k2 = h*f(r+0.5*k1, t+0.5*h)
        k3 = h*f(r+0.5*k2, t+0.5*h)
        k4 = h*f(r+k3, t+h)
        return (k1 + 2*k2 + 2*k3 + k4)
 
def f(r, t):
        alpha = float(input("Введите alpha"))
        beta = float(input("Введите beta "))
        gamma = float(input("Введите gamma"))
        sigma = float(input("Введите sigma"))
        x, y = r[0], r[1]
        fxd = x*(alpha - beta*y)
        fyd = -y*(gamma - sigma*x)
        return np.array([fxd, fyd], float)
 
h=0.001                               #edited
tpoints = np.arange(0, 30, h)         #edited
xpoints, ypoints  = [], []
r = np.array([2, 2], float)
for t in tpoints:
        xpoints.append(r[0])          #edited
        ypoints.append(r[1])          #edited
        r += rk4(r, t, h)             #edited; no need for input f
plt.plot(tpoints, xpoints)
plt.plot(tpoints, ypoints)
plt.xlabel("Time")
plt.ylabel("Population")
plt.title("Lotka-Volterra Model")
plt.savefig("Lotka_Volterra.png")
plt.show()

import matplotlib.pyplot as plt
import numpy as np
 
 
def rk4(r, t, h):  # edited; no need for input f
    """ Runge-Kutta 4 method """
    k1 = h * f(r, t)
    k2 = h * f(r + 0.5 * k1, t + 0.5 * h)
    k3 = h * f(r + 0.5 * k2, t + 0.5 * h)
    k4 = h * f(r + k3, t + h)
    return k1 + 2 * k2 + 2 * k3 + k4
 
 
def f(r, t):
    x, y = r[0], r[1]
    fxd = x * (alpha - beta * y)
    fyd = -y * (gamma - sigma * x)
    return np.array([fxd, fyd], float)
 
 
alpha = float(input('alpha: '))
beta = float(input('beata: '))
gamma = float(input('gamma: '))
sigma = float(input('sigma: '))
 
 
h = 0.001  # edited
tpoints = np.arange(0, 30, h)  # edited
xpoints, ypoints = [], []
r = np.array([2, 2], float)
for t in tpoints:
    xpoints.append(r[0])  # edited
    ypoints.append(r[1])  # edited
    r += rk4(r, t, h)  # edited; no need for input f
plt.plot(tpoints, xpoints)
plt.plot(tpoints, ypoints)
plt.xlabel("Time")
plt.ylabel("Population")
plt.title("Lotka-Volterra Model")
plt.savefig("Lotka_Volterra.png")
plt.show()