import numpy as np

z2i = 600
z1i = 500
z2f = 1000
Dt2 = 300
Dt1 = 350

z2 = np.linspace(z2i,z2f,11)
z1 = np.zeros(11)
for i in range(11):
    z1[i] = z1i-((Dt2/Dt1)**2)*(z2[i]-z2i)


#sampai sini nilai z1 dan z2 sudah diketahui semua

tol=1e-4
xold=200
D=4
rho=1
myu=0.01

Le=2e4
g=981

#Subroutine 1: F(x)
def fungsi(xi):
    v=xi
    Q=np.pi/4*D**2*v
    Hm=3718.5-2.3496*Q+7.8474e-4*Q**2-9.5812e-8*Q**3
    Re=rho*v*D/myu
    f=0.0596/(Re**0.215)
    F=600-500+f*Le*v**2/(2*g*D)-Hm  # ini masukin z2 z1 nya manual soalnya ak nga bisa nge loop nya
    return F

def dfungsi(xi):
    eps = 1e-5
    fplus = fungsi(xi+eps)
    fmin = fungsi(xi-eps)
    dfxi = (fplus-fmin)/(2*eps)
    return dfxi



tol = 0.01
iterasi = 1
xold = 200
fold = fungsi(xold)
dfold = dfungsi(xold)
x = np.array([xold])
fx = np.array([fold])
xnew = xold - fold/dfold
ea = abs((xnew-xold)/(xnew))*100



while ea >= tol:
    iterasi += 1
    xold = xnew
    fold = fungsi(xold)
    dfold = dfungsi(xold)
    x = np.append(x,xold)
    fx = np.append(fx,fold)
    xnew = xold-(fold/dfold)
    ea = abs((xnew-xold)/(xnew))*100
    fnew = fungsi(xnew)
    satuperv = 1/xnew




tabel=np.zeros([11,5])
tabel[:,0]= z2
tabel[:,1]= z1
tabel[:,2]= xnew
tabel[:,3]= fnew
tabel[:,4]= satuperv
header = ['z2 ', 'z1' , 'v' , 'f(v)' , '1/v']
garis = 55*('_')
print(garis)
print('{:^1s} {:^15s} {:^5s} {:^15s} {:^13s}'.format(*header))
print(garis)
for baris in tabel:
    print('{:>1.2f}{:>10.3f}{:>10.2f}{:>15e}{:>15e}'.format(*baris))