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what does this iteration do?

I'm working on an existing code and don't understand what the following iteration iterates over:

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  1. rows = dim[0];
  2. pagesize = dim[0]*dim[1];
  4.     for(ix=1;ix<dim[0]-1;ix++) 
  5.         for(iy=1;iy<dim[1]-1;iy++) 
  6.             for(iz=1;iz<dim[2]-1;iz++) 
  7.             {
  8.                 index   = ix + iy*rows + iz*pagesize;
  9.                                if(MASK[index]==0)
  10.                                      Gradient[index]=0;
  11.                                else
  12.                                   (...)
  13.                         }
I mean what is index exactly? MASK is an array of dimensions
dim[0] x dim[1] x dim[2] but index doesnt seem to me to iterate ovaer all elements of MASK (this can for example seen by the fact the first iteration gives index=1+rows+pagesize=1+rows*(1+dim[1]))

EDIT: to be precise MASK is imported from Matlab in the following way:
in the mexfunction there is
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  1. MASK = mxGetPr(prhs[1]);
hence, Mask is a pointer to the second input element from the calling matlab function. And this calling Matlab function has as second argument an array of ones and zeros of the dimensions dim[0] x dim[1] x dim[2].

I hope it is clear.
Feb 8 '08 #1
1 1397
Mo need to reply anymore, it took me an afternoon but I figured it out, thanks in case someone tried to understand
Feb 8 '08 #2

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