import numpy as np
import matplotlib.pyplot as plt

T = 100
h = 0.01

a=1.5 #a ma być >0!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!11
y_max=70
temp=22
y_min=10
M=3

#schemat Eulera: x = x + h * (f)

t = np.arange(0,T,h)
x = np.ones(t.size)
e = np.ones(t.size)
u = np.zeros(t.size)

x[0]=1
e[0]=temp-x[0]
for i in range(t.size - 1):
    e[i+1] = temp-x[i]
    print(e[i])

    if e[i+1]>M:
        u[i+1]=y_max
    elif e[i+1]<-M:
        u[i+1]=y_min
    elif e[i+1]>=-M or e[i+1]<M:
        u[i+1]=temp

    #x[i + 1] = x[i] + h * (a* x[i] + u[i])
    x[i + 1] = x[i] + h * ((u[i]-x[i])/a)

plt.subplot(311)
plt.plot(t, x, label='x')
plt.hlines(temp,0, T,'r', 'dashed') # temp, rysuj od 0, do T, red, dashed
plt.legend(loc='upper right')
plt.xlabel('t')
plt.ylabel('x')
#plt.axis([40, 47, y_min, y_max])
plt.axis([0, 10, temp-2, temp+2])

#plt.ylim([0, 7])
plt.subplot(312)
plt.plot(t, e, label='e')
plt.legend(loc='upper right')
plt.xlabel('t')
plt.ylabel('e')
plt.hlines(0,0, T,'r', 'dashed')
plt.axis([0, 100, -10, 5])

plt.subplot(313)
plt.plot(t, u, label='u')
plt.legend(loc='upper right')
plt.xlabel('t')
plt.ylabel('u')
plt.axis([0, 100, y_min-5, y_max+5])

plt.show()

#histereza, wytłumaczenie jak działa