For loop not initiated

So, I have created a matrix called cent in another for loop, and then:

for

... creates "cent"

end

e = 5 ;

per = zeros(e,e)

for u = 1:e
  rsum = 0; 
    a = 0; 
 for p=1:e   
     u
     p

Xdiff = 0;

Ydiff = 0;

Zdiff = 0;

    Xdiff = (cent(u,1)-cent(:,1)).^2
    Ydiff = (cent(u,2)-cent(:,2)).^2
    Zdiff = (cent(u,3)-cent(:,3)).^2
      a = (Xdiff + Ydiff  + Zdiff).^0.5

 rsum = cent(u,6) + cent(:,6)  ; 

 if a == rsum(p) 

   per(p,u) = p ; 
 else
    per(p,u) = 0 ; 
 end 
  end 
 end

The script runs just fine, and I get no error messages. However, i get no display of u and p, and per is returned as a matrix with only zeros if i create it before the first for loop. If i create per as shown below, between the two loops, it is not created at all. I thus think that the code never enters the second loop and run it. Why?

Answer 1

[Thorsten]

I have created some sample values for cent and the program runs just fine, entering the second loop as expected. The reason that per is all zero is that the condition

a == rsum(p)

is never true.

[Jonathan Oekland Torstensen]

Are you sure? Because it never displays p or u in the promt, which it should if it runs the loop.

[Jonathan Oekland Torstensen]

Im pretty sur it doesnt run, because I get that per is undefined after running the code.

[Jonathan Oekland Torstensen]

Any other suggestions?

[Image Analyst]

Use the debugger to step through the code line by line and examine variables and see where it goes. That's what everyone does.