zlatni rez

import numpy as np
import matplotlib.pyplot as plt
import scipy.optimize as opt

def A(r):
    V = 0.2
    return 2*r**2*np.pi + 2*V/r

def gs(f, xl, xd, eps):
    psi = (np.sqrt(5)+1)/2
    yl, yd = f(xl), f(xd)
    xul = xl + ratio*(xd-xl)
    xud = xd - ratio*(xd-xl)
    yul, yud = f(xul), f(xud)

    eps = 0.05
    err = 1
    maxit = 100
    it = 0
    while it < maxit and err > eps: #greska veca od prihvatljive greske
        it += 1
        if yul < yud:
            xl = xl
            xd = xud
        else:
            xd = xd
            xl = xul
        xul = xl + ratio*(xd-xl)
        xud = xd - ratio*(xd-xl)
        yul, yud = f(xul), f(xud)
        err = np.abs(xud - xul)

    return (xul + xud)/2

rmin, rmax = 0.05, 1.5
r = np.linspace(rmin, rmax, 200)
a = A(r)

plt.plot(r, a, color = 'salmon', lw = 2, ls = '-')
plt.xlabel('polumjer [m]')
plt.ylabel('povrsina lima')
plt.title('optimalni dizajn sic!')
plt.grid()
plt.savefig('zlatni_rez.png') #sejvanje
plt.show()