Set default value for precision parameter.

src/@dseries/round.m

@@ -9,7 +9,7 @@ function o = round(o, n) % --*-- Unitary tests --*--
 % OUTPUTS
 % - o [dseries]
 
-% Copyright (C) 2020 Dynare Team
+% Copyright (C) 2020-2021 Dynare Team
 %
 % This file is part of Dynare.
 %
@@ -26,6 +26,10 @@ function o = round(o, n) % --*-- Unitary tests --*--
 % You should have received a copy of the GNU General Public License
 % along with Dynare.  If not, see <http://www.gnu.org/licenses/>.
 
+if nargin<2 || isempty(n)
+    n = 0;
+end
+
 o = copy(o);
 o.round_(n);