/*
 *  call-seq:
 *     dvector.floor   ->  a_dvector
 *  
 *  Returns of copy of _dvector_ with each entry x replaced by largest integer not greater than x.
 *     
 *     a = Dvector[ 1.1, -2.2, 5.3 ]
 *     a.floor   -> Dvector[ 1, -3, 5 ]
 */ 
VALUE dvector_floor(VALUE ary) {