function o = flip_(o)

% Flips the rows in the data member (without changing the
% periods order)
%
% INPUTS
% - o [dseries]
%
% OUTPUTS
% - o [dseries]

% Copyright © 2020-2023 Dynare Team
%
% This file is part of Dynare.
%
% Dynare is free software: you can redistribute it and/or modify
% it under the terms of the GNU General Public License as published by
% the Free Software Foundation, either version 3 of the License, or
% (at your option) any later version.
%
% Dynare is distributed in the hope that it will be useful,
% but WITHOUT ANY WARRANTY; without even the implied warranty of
% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
% GNU General Public License for more details.
%
% You should have received a copy of the GNU General Public License
% along with Dynare.  If not, see <https://www.gnu.org/licenses/>.

for i=1:vobs(o)
    if isempty(o.ops{i})
        o.ops(i) = {['flip(' o.name{i} ')']};
    else
        o.ops(i) = {['flip(' o.ops{i} ')']};
    end
end

o.data = flipud(o.data);

return % --*-- Unit tests --*--

%@test:1
% Define a dates object
data = [transpose(1:3) transpose(4:6)];
o = dseries(data);
q = o;
r = copy(o);

% Call the tested routine.
try
    o.flip_();
    t(1) = true;
catch
    t(1) = false;
end

if t(1)
     t(2) = dassert(o.data, [3 6; 2 5; 1 4]);
     t(3) = dassert(q.data, [3 6; 2 5; 1 4]);
     t(4) = dassert(r.data, data);
     t(5) = dassert(o.name{1}, 'Variable_1') && dassert(o.name{2}, 'Variable_2');
     t(6) = dassert(q.name{1}, 'Variable_1') && dassert(q.name{2}, 'Variable_2');
     t(7) = dassert(r.name{1}, 'Variable_1') && dassert(r.name{2}, 'Variable_2');
     t(8) = dassert(o.ops{1}, 'flip(Variable_1)') && dassert(o.ops{2}, 'flip(Variable_2)');
     t(9) = dassert(q.ops{1}, 'flip(Variable_1)') && dassert(q.ops{2}, 'flip(Variable_2)');
end

T = all(t);
%@eof:1

%@test:2
% Define a dates object
data = [ones(10,1), -ones(10,1)];
o = dseries(data);
q = o;
r = copy(o);

% Call the tested routine.
try
    o.abs_();
    t(1) = true;
catch
    t(1) = false;
end

if t(1)
     t(2) = dassert(length(o.name), 2);
     t(3) = dassert(o.name{1},'Variable_1');
     t(4) = dassert(o.name{2},'Variable_2');
     t(5) = dassert(q.name{1},'Variable_1');
     t(6) = dassert(q.name{2},'Variable_2');
     t(7) = dassert(r.name{1},'Variable_1');
     t(8) = dassert(r.name{2},'Variable_2');
     t(9) = dassert(o.ops{1},'abs(Variable_1)');
     t(10) = dassert(o.ops{2},'abs(Variable_2)');
     t(11) = dassert(q.ops{1},'abs(Variable_1)');
     t(12) = dassert(q.ops{2},'abs(Variable_2)');
     t(13) = isempty(r.ops{1});
     t(14) = isempty(r.ops{2});
end

T = all(t);
%@eof:2
