function oo_ = sim1_purely_forward(options_, M_, oo_)
% Performs deterministic simulation of a purely forward model

% Copyright (C) 2012-2015 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 <http://www.gnu.org/licenses/>.

    ny0 = nnz(M_.lead_lag_incidence(1,:)); % Number of variables at current period
    iyf = find(M_.lead_lag_incidence(2,:)>0); % Indices of variables at next period

    if ny0 ~= M_.endo_nbr
        error('SIMUL: all endogenous variables must appear at the current period')
    end
    
    model_dynamic = str2func([M_.fname,'_dynamic']);

    oo_.deterministic_simulation.status = 1;

    for it = options_.periods:-1:1
        yf = oo_.endo_simul(:,it+1); % Values at next period, also used as guess value for current period
        yf1 = yf(iyf);
       
        [tmp, info] = solve1(model_dynamic, [yf; yf1], 1:M_.endo_nbr, 1:M_.endo_nbr, ...
                             1, options_.gstep, options_.solve_tolf, ...
                             options_.solve_tolx, options_.simul.maxit, ...
                             options_.debug,oo_.exo_simul, M_.params, oo_.steady_state, ...
                             it+M_.maximum_lag);

        if info
            oo_.deterministic_simulation.status = 0;
        end

        oo_.endo_simul(:,it) = tmp(1:M_.endo_nbr);
    end
