o re-order the input 
               array. The first element of iorder is the index of 
               the first item of the re-ordered array, and so on. 

               Note that the order imposed by <b>reordl_c</b> is not the 
               same order that would be imposed by a sorting 
               routine. In general, the order vector will have 
               been created (by one of the order routines) for 
               a related array, as illustrated in the example below. 

               The e