Help with Dependency question

[shreyas krishnan]

Hi, 
        For this simple loop, I get the following distance and direction vector 

Distance {1,-1) 
Direction  (2,0) 

for(J = 1; J <= N-1; J++)
    for(I = 1; I <= N-1; I++)
      {
        XX = X[I+1][J];
        XY = X[I][J+1];
    } 


Can some body explain why thats so ? 
thanks
Shreyas