n=7;

A=5*eye(n) -diag(ones(1,n-1),1)- diag(ones(1,n-1),-1);

b = [4,3* ones(1,n-2),4]';


x0 = zeros(size(b));

[x, nit] = jacobi(A,b, x0,10^(-5), 1000);

[x, nit] = gaussseidel(A,b, x0,10^(-5), 1000);

A = [10 7 8 7; 7 5 6 5; 8 6 10 9; 7 5 9 10];
b=[32;23;33;31];

x = A^-1*b
trueB = b;
trueX = x;
trueA = A;

A = [10 7 8 7; 7 5 6 5; 8 6 10 9; 7 5 9 10];



b=[32.1;22.9;33.1;30.9];

x = A^-1*b
norm(trueX-x,inf)/norm(trueX,inf)
norm(trueB-b,inf)/norm(trueB,inf)
cond(A)

A = [10 7 8.1 7.2; 7.8 5.04 6 5; 8 5.98 9.89 9; 6.99 4.99 9 9.98];
b=[32;23;33;31];
x = A^-1*b

cond(A)

norm(trueX-x,inf)/norm(trueX,inf)
norm(trueA-A,inf)/norm(trueA,inf)