Метод простых итераций для решения

A = [
[4,-1,2],
[1,-5,3],
[2,-6,-8]]
B = [2, 3, -8]

A = [
[4,-1,2],
[1,-5,3],
[2,-6,-8]]
B = [2, 3, -8]
 
# точность итераций
c = 12
eps = 1/10**c
x = []
n = len(A)
for j in range(n):
    k = A[j][j]
    for i in range(n):
        A[j][i] /= -k 
    A[j][j] = 0
    B[j] /= k 
 
# r - счетчик итераций
r = 0
x = B.copy()
tmp = sum(x) + 2*eps
while abs(sum(x)-tmp) > eps:
    tmp = sum(x)
    t = [0]*n
    for i in range(n):
        t[i] = sum(x[j]*A[i][j] for j in range(n)) + B[i]
    r += 1
    x = t.copy()
    
print(*(round(elem) for elem in x))
print(r)

import numpy as np
A = [
[4,-1,2],
[1,-5,3],
[2,-6,-8]]
B = [2, 3, -8]
 
# точность итераций
eps = 1e-4
 
a = np.array(A)
diag = (1/np.diag(a)).reshape(-1,1)
a[np.diag_indices_from(a)] = 0.
a = np.hstack((-a, np.array(B).reshape(-1, 1))) * diag
x = a[:,-1].ravel()
x = np.append(x, 1)
 
tmp = x.copy() + eps
cnt = 0
while abs(x-tmp).sum() > eps:
    tmp = x.copy()
    x = a.dot(x)
    x = np.append(x, 1)
    cnt += 1
 
print(x[:-1].round(), cnt)