Question

I correct the code with help of Stackfriends, see the bold parts, if anybody else has the similiar stack.
Arithmeticaly, I should take w=1 and why get I w=2? Thanks a lot,

X=linspace(0,10,6);
Y=linspace(0,20,5);
    Xstar=0;
    Ystar=0;
    **p=0;**
     for i=1:length(X)-1
         for j=1:length(Y)-1
              if (Ystar==Y(j)) && (Xstar==X(i))
                  w=1;
              else
                  w=2;
              end
              **p(i,j)=w**
         end
     end

Answer 1

Just a guess, but i think you want to loop through the arrays backwards. You should use the debugger and look at it step by step.

Try this:

...
    for i=length(X):-1:1
         for j=length(Y):-1:1
              if (Ystar==Y(j)) && (Xstar==X(i))
                  w=1;
              else
                  w=2;
              end
         end
     end

Here is what you should do to solve the problem.

• set a breakpoint at the beginning of the loop (klick in matlab editor window next to source code, a red point should appear)
• press F5 to start your script, it will stop at your breakpoint
• press F10 to step line by line trough your script, at the same time you can examine the values of your variables e.g. in your workspace window

(I hope these instructions are still valid, I have a rather old version of MATLAB)