functions in slice3.i - t

    to_corners(list, ni, nj)  


convert a LIST of cell indices in an (NI-1)-by-(NJ-1)-by-(nk-1)  
logically rectangular grid of cells into the list of  
2-by-2-by-2-by-numberof(LIST) cell corner indices in the  
corresponding NI-by-NJ-by-nk list of vertices.  
Interpreted function, defined at i/slice3.i   line 488