%DESCRIPTION may be bicausal

% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %% Version control history
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %% $Id$
% %% $Log$
% %% Revision 1.1  1996/11/01 12:18:38  peterg
% %% Initial revision
% %%
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


% Copyright (c) P.J. Gawthrop, 1996.

% Check that there is exactly one bonds.
if check_bonds(bonds,1,'SS')==0
  return
end

if (bonds(1)==0)|(bonds(2)==0) % Under causal
  status = -1;
else                          % causal
  status = 0;
end;

% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %% Version control history
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %% $Id$
% %% $Log$
% %% Revision 1.1  1996/11/01 12:05:54  peterg
% %% Initial revision
% %%
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


% Copyright (c) P.J. Gawthrop, 1996.

% Check that there are exactly two bonds.
if check_bonds(bonds,2,'TF')==0
  return
end


%Causality of TF is same as that of a junction
[bonds,status] = zero_cause(bonds);