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matlab-at-home/LU.m
2023-03-19 23:09:45 +02:00

33 lines
790 B
Matlab

# upper matrix ballocks.
clear,clc
#U2 = -A(2,1)/A(1,1) * A(1, :) + A(2, :)
#U3 = -A(3,1)/A(1,1) * A(1, :) + A(3, :)
#U_temp = [A(1,:); U2; U3]
#U3 = -A(3,2)/U_temp(2,2) * U_temp(2, :) + U_temp(3, :)
#U = [A(1,:); U2; U3]
#L = [1, 0, 0; A(2,1)/A(1,1),1,0;(A(3,1)/A(1,1)),(A(3,2)/U_temp(2,2)),1]
# U_temp var = A (matrix)
# for i < n
# j = i + 1
# for j <= n
# U_temp(j, :) = -U_temp(j,i)/U_temp(j,i) * U_temp(i, :) + U_temp(j, :)
A = [5,2,4;2,1,1;1,-5,-3];
b = [17;0;13;];
U_temp = A
L_temp = eye(3);
for i = [1:length(A)-1]
for j = [i+1: length(A)]
L_temp(j,i) = U_temp(j,i)/U_temp(i,i);
U_temp(j, :) = -U_temp(j,i)/U_temp(i,i) * U_temp(i, :) + U_temp(j, :);
endfor
endfor
U_temp
L_temp
#another for loop that's like we create another matrix for Z
L_temp*U_temp\b