function [a,b] = ffill(x,ixc,y)

% function [a,b] = ffill(x,ixc,y)
% Makes the horizontale concatenation if x exists
% and fills the matrix with 0 if x and y are not the same size.
%
% INPUTS
%    x:         matrix
%    ixc:       vector of indices
%    y:         matrix
%        
% OUTPUTS
%    a:         concatenation results
%    b:         vector
%        
% SPECIAL REQUIREMENTS
%    none
%  
% part of DYNARE, copyright Dynare Team (2001-2008)
% Gnu Public License.


xc = size(x,1) ;

if isempty(y)
  b = [ixc; 0];
  a = [x zeros(size(x,1),1)];
else
  yc = size(y,1) ;
  b = [ixc;yc] ;

  if xc > yc
    a = [x [y;zeros(xc-yc,size(y,2))]] ;
  elseif yc > xc
    a = [[x;zeros(yc-xc,size(x,2))] y] ;
  else
    a = [x y] ;
  end

end

% 2001/09/1 MJ corrected for absent lags