Index in position 2 exceeds array bounds (must not exceed 4).

data=[0   1   0   0.1j
   1   6   0 0.6j
   1   3   0 0.2j
   3   6   0 0.5j
   3   4   0 0.2j
   4   6   0 0.3j
   2   4   0 0.4j
   1   2   0 0.2j
   2   5   0 0.3j
   6   7   0 0.4j];  

[row,col]=size(data);
order=col

for m=1:row
    data(m,8)=1/(data(m,7)+data(m,8));
end

Z2adm=data;
Y=zeros(order,order);

for i=1:row
    for j=1:order
        if data(i,1)==0||data(i,2)==0    
           a=0;
        elseif data(i,1)~=0||data(i,2)~=0
            Y(data(i,1),data(i,2))=-data(i,8);
            Y(data(i,2),data(i,1))=-data(i,8);
        end
        
    end
end
%2-digonal values 
for a=1:order     %for k
    for b=1:row
        if data(b,1)==a ||data(b,2)==a
           
            Y(a,a)=(Y(a,a)+data(b,8));
        end
    end
   
end
Ybus=Y

Answer 1

[Guillaume]

I don't know what else you expect from your code. You purposefully create an array data with 4 columns and then write:

 .. = 1/(data(m,7)+data(m,8))

which sums columns 7 and 8 of an array with only 4 columns.

The error message is correct. Either create an array with enough columns or don't index inexistant columns.