MATLAB: Index out of bounds because size(Z_wire)

indexing

Hi I'm trying to execute a program but i keep getting this error:
>> inductanceTest (1,2,4,4,1)
Attempted to access Z_wire(2,2,4); index out of bounds because size(Z_wire)=[1,0,1].
Error in inductanceTest (line 52)
    L0 = L0 + Z_wire (z(1,i),w,h);
I do not understand what does it mean. Is someone ready to help me?
here is the code
function [ inductance ] = inductance( N,w,h,d_in,s)
u = pi*4e-7;
r_in = d_in/2;
p = w+s;
k= w+h;
%THE LENGHTH AND THE DISTANCE OF THE TRACKS FROM CENTER:
     z(1:2,1)  = [r_in     r_in];
     z(1:2,2)  = [d_in   -r_in];
     z(1:2,3)  = [d_in   -r_in];
     z(1:2,4)  = [r_in+p   r_in];
if N==1
    z(1:2,5)  = [r_in     r_in+p];
else
      z(1:2,5)  = [d_in+p     r_in+p];
end
for i = 6:1:4*N+1
      z(1:2,i)  = [z(1,i-4)+2*p     z(2,i-4)+ sign z(2,i-4)] ;
      if i==4*N+1
       z(1:2,i)  = [z(2,i-1)         z(2,i-4)+  sign z(2,i-4)] ;
      end 
end
   Z_wire = (log(2)*z(1,i)/0.22/k)- 1.25 + ((k/3*z(1,i))+ (u/4));
L0 = 0;
for i = 1:1:4*N+1
    L0 = L0 + Z_wire (z(1,i),w,h);
end

Best Answer

You have
for i = 6:1:4*N+1
N is 1 in your test, so that is
for i = 6:1:4*1+1
which is
for i = 6:5
in which the end point is less than the start point. In this case, the body of the loop is not executed, and i is set to []
Then the next line of code after the loop is
   Z_wire = (log(2)*z(1,i)/0.22/k)- 1.25 + ((k/3*z(1,i))+ (u/4));
but i is empty, so z(1,i) is empty. When you combine an empty expression with other expressions using * or + the result is empty, so Z_wire ends up being empty.
Then you enter the for i = 1:1:4*N+1 loop, and have problems accessing Z_wire elements because Z_wire is empty.
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