for loop only gives me one value

hello, i'm trying to write this code, however when I calculate xi it keep giving me one value, even though both alpha_g and ki_1 has 6 values. which then stops me from calculating yi with the following error

Index exceeds the number of array elements (1).

Error in Module_b (line 44)

yi(i)=xi(i).*ki_1(i);

this is the code:

for i=1:nc

if (min<alpha_g(i)&&alpha_g(i)<max)

for i=1:nc

xi(i)= z1./(1+alpha_g(i).*(ki_1(i)-1));

for i=1:nc

yi(i)=xi(i).*ki_1(i);

end

end

elseif alpha_g>=1

yi=z1;

else

xi=z1;

end

end

Answer 1

[David Hill]

Only one loop is needed.

for m=1:nc  %don't use the same indexing variable (you are already inside a loop)
  xi(m)= z1./(1+alpha_g(m).*(ki_1(m)-1));
  yi(m)=xi(m).*ki_1(m);
end

Answer 2

[Torsten]

You only set xi(1) in

for i=1:nc
   xi(i)= z1./(1+alpha_g(i).*(ki_1(i)-1)); 

but refer to xi(1) up to xi(6) in the following loop

   for i=1:nc
       yi(i)=xi(i).*ki_1(i);
   end   

Furthermore, since there are nested loops in your code fragment, you cannot use the same loop index "i" every time.

[Eyad Alkhotani]

I didn't understant, I thought by referring i to be from 1 to nc that means that I'm referring for xi from 1 to nc(6)

[Torsten]

For this, you have to close the first for-loop:

for i=1:nc
    xi(i)= z1./(1+alpha_g(i).*(ki_1(i)-1)); 
end
for i=1:nc
    yi(i)=xi(i).*ki_1(i);
end   

or simply

for i=1:nc
    xi(i)= z1./(1+alpha_g(i).*(ki_1(i)-1)); 
    yi(i)= xi(i).*ki_1(i);
end