/*
 *  call-seq:
 *     dvector.floor!   ->  dvector
 *  
 *  Replace each entry x of _dvector_ with the largest integer not greater than x.
 *     
 *     a = Dvector[ 1.1, -2.2, 5.3 ]
 *     a.floor!   -> Dvector[ 1, -3, 5 ]
 *     a          -> Dvector[ 1, -3, 5 ]
 */ 
VALUE dvector_floor_bang(VALUE ary) {