I need assistance in writing a code to solve iteratively this non-linear problem that I have broken down in the example below;

Q1 = [ 25, 10, 15, 20; 10, 12, 18, 23; 12, 15, 17,19; 15 20, 16, 28 ];
F1 = [ 6;7;12;7];
F2 = [ 48;64;72;75];

iter = 0;
N = 100; % maximum number of iterations
uold = u0;
QA         = Q1;
F1         = RF1;
F2         = RFM; % max load capacity
u0         = u1;
dF         = 0.2;
[row,col]  = size(u);
tol = 0.0001;
syms 'u'
R1 = F2 - F1;
u2 = inv(Q1)*R1;
u3 = u0 + u2;
F3 = F1 + dF;
R2 = F2 - F3; % unbalanced force must be equal to 0 in order to converge
Q2 = F3\u3;
u4 = inv(Q2)*R2;
u5 = u3 + u4;
F4 = F3 + dF;
R3 = F2 - F4;
Q3 = F4\u5;
u6 = inv(Q3)*R3;
u7 = u5 + u6;
F5 = F4 + dF;
R4 = F2 - F5;
Q4 = F5\u7;
u8 = inv(Q4)*R4;
u9 = u7 + u8;
F6 = F5 + dF;
R5 = F3 - F6;

[John D'Errico]

Was it really nevessary to completely repost your question when all you had to do was fix an error in the first line of the code? Please don't keep reposting your question. I closed the last one.

Anyway, what assistance do you think you need? It seems like there is no iteration. You wrote a finite piece of code. It appears like it will run. What is iterative?

[George Adomako Kumi]

I just want to create a code using the steps above to solve a much complex problem but I just used random numbers in this example. Iterative means step-by-step procedure.

[Steven Lord]

Let's take a step back. You've posted a bunch of code but no explanation of the problem you're trying to solve. Start at the beginning and explain in words (no code) the problem you're trying to solve. Assume we don't know much about your field of study (because for at least some of us, that's probably a valid assumption.) Once we know that we'll have the context that may allow us to help you write / improve the code.

[George Adomako Kumi]

This is the first part of the code i am trying to solve. It works by first finding the residual which is the difference in the initial force F1 and F2. Based on that, I will find u2 which happens to be the inverse of Q1 and the residual R1. u3 is also defined as the summation of u0 and u2. I have to further increase the F1 by dF to obtain F3. The last step is to find if the residual force is zero. A solution is obtained once this equals 0 if not the cycle continues until I obtain a value as the difference between the residual F and F2 (MAXIMUM VALUE).

Thanks

Q1 = [ 25, 10, 15, 20; 10, 12, 18, 23; 12, 15, 17,19; 15 20, 16, 28 ];

F1 = [ 6;7;12;7];

F2 = [ 48;64;72;75];

u1 = [ 2;2;3;4];

iter = 0;

N = 100; % maximum number of iterations

uold = u0;

QA = Q1;

F1 = RF1;

F2 = RFM; % max load capacity

u0 = u1;

dF = 0.2;

[row,col] = size(u);

tol = 0.0001;

syms 'u'

R1 = F2 - F1;

u2 = inv(Q1)*R1;

u3 = u0 + u2;

F3 = F1 + dF;

R2 = F2 - F3; % residual force must be equal to 0 in order to converge