# CRANK_01.py
# Calculation of Dynamic Heat Flow
# Example 1 in Bagda, Dlabal, Öztürk
# Calculation of temperature change in a wall  of cellular concrete
# at 20 °C,  if one side is cooled down to 0 °C.
# System design by Engin Bagda, Python programming by Erkam Talha Öztürk
# Version 2020_07_03
import numpy as arr  # to set up arrays


# Crank Nicolson function
def CrankNicolson():
    e[0] = 0
    f[0] = Temp[0]
    for i in range(1, n - 1, 1):  # n-1 because string has to run until i=19
        r = Lambda[i] * dTime / (Wkap[i] * Rho[i] * x[i] * x[i])
        K1 = Lambda[i - 1] * x[i] / (Lambda[i] * x[i - 1])
        K2 = Lambda[i] * x[i + 1] / (Lambda[i + 1] * x[i])
        a = r
        b = 2 + (2 * r)
        c = r
        d = (a * Temp[i - 1]) + (2 - (2 * r)) * Temp[i] + (c * Temp[i + 1])
        e[i] = c / (b - (a * e[i - 1]))
        f[i] = (d + a * f[i - 1]) / (b - a * e[i - 1])


# Thomas algorithm
def ThomasAlgorithm():
    for i in range(n - 2, 0, -1):  # n-1 because string has to start i=18
        Temp[i] = (e[i] * Temp[i + 1]) + f[i]


# Definitions
global e, f, r, K1, K2, a, b, c, d  # in Ctank Nicolsen function
global dTemp  # in Thomas algorithm
global n, x, Temp, Lambda, Rho, Wkap, dTime  # in main run

n = 20  # index for layers from i=0 to i=20

x = arr.empty(n)
e = arr.empty(n)
f = arr.empty(n)
Temp = arr.empty(n)
Lambda = arr.empty(n)
Rho = arr.empty(n)
Wkap = arr.empty(n)

# Setup of conditions and  material properties

dTime = 60.00  # s, duration of the time steps

for i in range(0, n, 1):  # string stops at i=n-1
    x[i] = 0.010  # thickness of each element
    Lambda[i] = 0.160  # thermal conductivity (W/m/K)
    Rho[i] = 550  # density (kg/m3)
    Wkap[i] = 1000  # heat capacity (oule/m3)
    Temp[i] = 20  # °C, primary definition

# Main run
for Time in range(0, 1440, 1):  # ammount of time steps  24 hours x 60 minutes
    Temp[n - 1] = (
        0  # °C new temperature after 1 minute (boundary condition in elemnt i=n-1
    )
    CrankNicolson()
    ThomasAlgorithm()

    print(
        "%4.0f, %6.1f, %8.1f, %8.1f, %8.1f, %8.1f, %8.1f, %8.1f, %6.1f "
        % (
            Time,
            Temp[0],
            Temp[1],
            Temp[2],
            Temp[3],
            Temp[n - 4],
            Temp[n - 3],
            Temp[n - 2],
            Temp[n - 1],
        )
    )

# End of run