1function trend = lineartrend(o) % --*-- Unitary tests --*-- 2 3% Returns a trend centered on zero. 4% 5% INPUTS 6% - o [dseries] time series with T observations. 7% 8% OUTPUTS 9% - trend [double] T*1 vector, linear trend with mean zero. 10% 11% REMARKS 12% the generic element of the returned argument is trend(i) = i - (n+1)/2. 13 14% Copyright (C) 2017 Dynare Team 15% 16% This file is part of Dynare. 17% 18% Dynare is free software: you can redistribute it and/or modify 19% it under the terms of the GNU General Public License as published by 20% the Free Software Foundation, either version 3 of the License, or 21% (at your option) any later version. 22% 23% Dynare is distributed in the hope that it will be useful, 24% but WITHOUT ANY WARRANTY; without even the implied warranty of 25% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 26% GNU General Public License for more details. 27% 28% You should have received a copy of the GNU General Public License 29% along with Dynare. If not, see <http://www.gnu.org/licenses/>. 30 31trend = transpose(1:o.nobs)-.5*(o.nobs+1); 32 33return 34 35%@test:1 36a = dseries(randn(100,3)); 37try 38 trend = a.lineartrend; 39 t(1) = 1; 40catch 41 t(1) = 0; 42end 43 44if t(1) 45 t(2) = abs(mean(trend))<1e-12; 46end 47T = all(t); 48%@eof:1