/* * call-seq: * dtable.sum -> number * * Returns the sum of the entries in _dtable_. Returns 0.0 if * _dtable_ is empty. * * a = Dtable.new(2,4) * a.set_column(0, Dvector[1,2,3,4]) * a.set_column(1, Dvector[0, 1, 0, 1]) * a.sum -> 12.0 * Dtable.new(2,2).sum -> 0.0 */ VALUE dtable_sum(VALUE tabl){