AAE-NA-Labs/01_Direct-Methods-for-Solving-Linear-Systems/Code/main.m
Sergiusz Warga a3fa9eb91d refac
2023-03-11 20:08:05 +01:00

78 lines
1.0 KiB
Matlab

%% Problem 1
clear all;
clc;
A = [2, -1, 0, 0;
-1, 2, -1, 0;
0, -1, 2, -1;
0, 0, -1, 2];
b = [0;0;0;5];
B = Alg5([A b])
%% Problem 2
clear all;
clc;
A = [1, 1, 1;
1, 1, 2;
1, 2, 2];
b = [1;2;1];
[P, Q, L, U] = Alg2(A);
b = P*b;
% Ly = b and Ux = y
y = Alg3(L, b); % Forward substitution
x = Q*Alg4(U, y) % Backward substitution
%% Problem 4
A = [0.835, 0.667;
0.333, 0.266];
b = [0.168; 0.067];
bp = [0.168; 0.066];
kappa = cond(A)
B = Alg5([A b])
Bp = Alg5([A bp])
%% Problem 5
clear all;
clc;
A = [2, 1, 2;
1, 2, 3;
4, 1, 2];
[P, Q, L, U] = Alg2(A)
I = P*eye(3);
% Ly = b and Ux = y
y = Alg3(L, I); % Forward substitution
x = Q*Alg4(U, y) % Backward substitution
inv(A) - x
%% Problem 6
clc;
A = [1 2 3 4;
-1 1 2 1;
0 2 1 3;
0 0 1 1];
[L, U, P] = Alg8(A)
det(A) - prod(diag(U))
%% Problem 10
% A = [1 2 2 3 1;
% 2 4 4 6 2;
% 3 6 6 9 6;
% 1 2 4 5 3]
A = [0.835, 0.667;
0.333, 0.266];
b = [0.168; 0.067];
Alg6_RREF([A b])