function D = sparse_hessian_times_B_kronecker_C(varargin)

%@info:
%! @deftypefn {Function File} {@var{D} =} sparse_hessian_times_B_kronecker_C (@var{A},@var{B},@var{C},@var{fake})
%! @anchor{kronecker/sparse_hessian_times_B_kronecker_C}
%! @sp 1
%! Computes A*kron(B,C) where A is Hessian matrix in sparse format.
%! @sp 2
%! @strong{Inputs}
%! @sp 1
%! @table @ @var
%! @item A
%! mA*nA matrix of doubles.
%! @item B
%! mB*nB matrix of doubles.
%! @item C
%! mC*nC matrix of doubles.
%! @item fake
%! Anything you want, just a fake parameter (because the mex version admits a last argument specifying the number of threads to be used in parallel mode).
%! @end table
%! @sp 2
%! @strong{Outputs}
%! @sp 1
%! @table @ @var
%! @item D
%! mA*(nC*nB) or mA*(nB*nB) matrix of doubles.
%! @end table
%! @sp 2
%! @strong{Remarks}
%! @sp 1
%! [1] This routine is called by Dynare if and only the mex version is not compiled (also used for testing purposes).
%! @sp 1
%! [2] This routine can be called with three or four arguments. In the first case A*kron(B,B) is computed.
%! @sp 2
%! @strong{This function is called by:}
%! @sp 1
%! @ref{dr1}
%! @sp 2
%! @strong{This function calls:}
%! @sp 1
%! @ref{kronecker/A_times_B_kronecker_C}
%!
%! @end deftypefn
%@eod:

% Copyright © 1996-2025 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/>.

% Original author: stephane DOT adjemian AT univ DASH lemans DOT fr

A = varargin{1};
B = varargin{2};
C = varargin{3};
fake = varargin{nargin};

switch nargin
  case 4
    D = A_times_B_kronecker_C(A,B,C,fake);
  case 3
    D = A_times_B_kronecker_C(A,B,C);
  otherwise
    error('Two or Three input arguments required!')
end
