/* * call-seq: * dvector.acos -> a_dvector * * Returns of copy of _dvector_ with entry x replaced by acos(x). * * a = Dvector[ 0.1, -0.2, -0.3, 0.4 ] * a.acos -> Dvector[ acos(0.1), acos(-0.2), acos(-0.3), acos(0.4) ] */ VALUE dvector_acos(VALUE ary) {