/*
 *  call-seq:
 *     dvector.ceil   ->  a_dvector
 *  
 *  Returns of copy of _dvector_ with entry x replaced by smallest integer not less than x.
 *     
 *     a = Dvector[ 1.1, -2.2, 5.3 ]
 *     a.ceil   -> Dvector[ 2, -2, 6 ]
 */ 
VALUE dvector_ceil(VALUE ary) {