how can i make a general matrix?

i asked this question many times but still have a problem....someone help me please i need answer as soon as possible...

[John D'Errico]

I see you still have problem. However, the issue is you need to EXPLAIN clearly what you need. If you cannot explain what your goal is, how can you expect help?

Is this matrix symmetric? That is, is it true that x(i,j) == x(j,i) always? The rule for x12 that you show would seem to say that is true.

Would x(2,2) be the sum of 5 elements? Thus... sum(L([1 4 5 6 7],4))?

Finally, it really helps if you post actual code, rather than a PICTURE of code. For example, while I can look at the matrix L, I cannot paste it into MATLAB.

[arian hoseini]

thats on me and im sorry for my explanation

L =[1 2 0.1 0.2 0.02

1 4 0.05 0.2 0.02

1 5 0.08 0.3 0.03

2 3 0.05 0.25 0.03

2 4 0.05 0.1 0.01

2 5 0.1 0.3 0.02

2 6 0.07 0.2 0.025

3 5 0.12 0.26 0.025

3 6 0.02 0.1 0.01

4 5 0.2 0.4 0.04

5 6 0.1 0.3 0.03]

%-------------------------------Program strat her--------------------------

nl = L(:,1); nr = L(:,2); R = L(:,3);

X = L(:,4); Bc = j*L(:,5);

nbr=length(L(:,1)); nbus = max(max(nl), max(nr));

Answer 1

[Torsten]

function main
L = [1 2 0.1 0.2 0.02; ...
    1 4 0.05 0.2 0.02; ...
    1 5 0.08 0.3 0.03; ...
    2 3 0.05 0.25 0.03; ...
    2 4 0.05 0.1 0.01; ...
    2 5 0.1 0.3 0.02; ...
    2 6 0.07 0.2 0.025; ...
    3 5 0.12 0.26 0.025; ...
    3 6 0.02 0.1 0.01; ...
    4 5 0.2 0.4 0.04; ...
    5 6 0.1 0.3 0.03]; 
nl = L(:,1);
nr = L(:,2);
x  = L(:,4);
n  = numel(x);
Nb = 6;
mat = zeros(Nb,Nb);
n = numel(x);
for i = 1:Nb
  for j = 1:Nb
    logic = zeros(n,1);
    if i==j
      for k = 1:n
        logic(k) = nl(k)==i || nr(k)==i;
      end
    else
      for k = 1:n
        logic(k) = (nl(k)==i && nr(k) ==j) || (nl(k)==j && nr(k)==i);
      end  
    end   
    mat(i,j) = sum(x(logic==1));
  end
end  
mat
end

[arian hoseini]

thank u thats what i needed but what about the matrix diagonal....i explained that x11 is the sum of all x's whose nl=1 and nr=1 (for example x44=x45+x14+x24)

[Torsten]

Corrected.

[arian hoseini]

thank u so much.

Answer 2

[Cris LaPierre]

https://www.mathworks.com/learn/tutorials/matlab-onramp.html

[arian hoseini]

i dont have much time i need the code as soon as possible.

[Cris LaPierre]

That's not really how Answers works.

[arian hoseini]

x = zeros(Nb);
for i=1:Nb
    for j=1:Nb
        rowsToSum = L(:,1) == i & L(:,2) == j;
        x(i,j) = sum(L(rowsToSum, 4));
    end
end
disp(x)

i dont expect you to write the whole code for me so help me with this...i tried the top code but i get this

0 0.2000 0 0.2000 0.3000 0

0 0 0.2500 0.1000 0.3000 0.2000

0 0 0 0 0.2600 0.1000

0 0 0 0 0.4000 0

0 0 0 0 0 0.3000

0 0 0 0 0 0

for x11 i added this % x(i) = sum(L(rowsToSum, 4));

but still not working and as you see x21 should be like x12 but...the others are like this too