function o = center_(o, geometric)

% Centers dseries object o around its mean (arithmetic or geometric).
%
% INPUTS
%  - o             dseries object [mandatory].
%  - geometric     logical [default is false], if true returns the geometric mean.
%
% OUTPUTS
%  - o             dseries object.

% Copyright © 2016-2023 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/>.

if nargin<2
    geometric = false;
end

m = mean(o.data);

if geometric
    o.data = bsxfun(@rdivide, o.data, m);
else
    o.data = bsxfun(@minus, o.data, m);
end

for i=1:o.vobs
    if isempty(o.ops{i})
        o.ops(i) = {sprintf('center(%s, %s)', o.name{i}, num2str(geometric))};
    else
        o.ops(i) = {sprintf('center(%s, %s)', o.ops{i}, num2str(geometric))};
    end
end

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

%@test:1
% Define a dataset.
A = repmat([1.005, 1.05], 10, 1);

% Instantiate a time series object and compute the mean.
try
   ts = dseries(A);
   ts.center_(true);
   t(1) = 1;
catch
   t = 0;
end

if t(1)
   t(2) = all(all(abs(ts.data-ones(10,2))<1e-12));
   t(3) = dassert(ts.ops{1}, 'center(Variable_1, 1)');
   t(4) = dassert(ts.name{1}, 'Variable_1');
end
T = all(t);
%@eof:1
