function [port_bonds, status] = abg2cbg(system_name, ...
    system_type, full_name, ...
    port_bonds, port_bond_direction, port_status, typefile, infofile)

% abg2cbg - acausal to causal bg conversion
%
%     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
%     %%%%% Model Transformation Tools %%%%%
%     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% 
% Matlab function  abg2cbg.m
% Acausal bond graph to causal bond graph: mfile format
% [bonds,status] = abg2cbg(system_name, system_type, full_name, port_bonds, infofile)

% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %% Version control history
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %% $Id$
% %% $Log$
% %% Revision 1.22  1997/08/19 10:21:09  peterg
% %% Only copy port cuaslity info if not already set within the
% %% subsystem. I thought I'd done this already ....
% %%
% %% Revision 1.21  1997/08/18 16:25:25  peterg
% %% Minor bug fixes
% %%
% %% Revision 1.20  1997/08/18 12:45:24  peterg
% %% Replaced: comp_bonds = bonds(bond_list,:)
% %% by: 	for kk = 1:n_comp
% %% 	  comp_bonds(kk,:) = bonds(comp(kk),:);

  mtt_info(['m-file ', fun_name, ' does not exist'], infofile);
  bonds = [];
  status = [];
  return
end;

% Evaluate the system function to get the bonds and number of ports
eval(['[bonds,components,n_ports]=', fun_name, ',']);


% Find number of bonds
[n_bonds,columns] = size(bonds);
if (columns ~= 2)&(n_bonds>0)
  error('Incorrect bonds matrix: must have 2 columns');
end;

 
% Find number of components
[n_components,columns] = size(components);
if n_components==0 % there is nothing to be done
  return
end;

port_bond_direction

% Coerce the port (SS:[]) component bonds to have the same direction as
% of the bonds in the encapsulating system 
if n_ports>0
  port_bond_index = abs(components(1:n_ports,1)) % relevant bond numbers
  for i=1:n_ports
    % Is the direction different?
    if (sign(components(i,1))~=port_bond_direction(i))
      disp(sprintf("Flip port %i",i));
      % Flip direction at port
      components(i,1) = - components(i,1);
      % and at the other end
      for j=n_ports+1:n_components
	for k=1:columns
	  if (abs(components(j,k))==port_bond_index(i))
	    components(j,k) = - components(j,k);
	  end
	end
      end;
      % Flip the bond causalities (these are arrow-orientated)
      bonds(port_bond_index(i),:) = -bonds(port_bond_index(i),:);
    end
  end
end



% Set initial status
status = -ones(n_components,1);

% If not at top level, then copy the port bonds.
if ~at_top_level 
  % Find number of port bonds
  [n_port_bonds,columns] = size(port_bonds);

  % Check compatibility - if ok copy port bonds to the internal bonds list.
  if n_port_bonds~=n_ports
  mtt_info(sprintf('%s: %1.0f port bonds incompatible with %1.0f ports', ...
               full_name, n_port_bonds, n_ports), infofile);

  else % Copy the port bonds & status

    for j = 1:n_port_bonds
      jj = port_bond_index(j);
      for k = 1:2
	if bonds(jj,k)==0 % only copy if not already set
	bonds(jj,k) = port_bonds(j,k);
	end;
      end;
      status(1:n_ports) = port_status;
    end
  end
else
  n_port_bonds=0;
end;
% bonds,port_bonds

% Causality indicator
total = 2*n_bonds;
done = sum(sum(abs(bonds)))/total*100;

% Outer while loop sets preferred causality
ci_index=1; 

      % Invoke  the appropriate causality procedure
      if exist(cause_name)~=2 % Try a compound component
        % Port status depends on whether the corresponding bonds are
        %  fully causal at this stage.
        one = ones(n_bonds,1);
        port_status = (sum(abs(comp_bonds'))'==2*one) - one;
	% Direction of bonds on the ports (0 if next to port)
	port_bond_direction = -sign(components(i,1:n_bonds))';
	[comp_bonds,s] = abg2cbg(name, comp_type, full_name, 
            comp_bonds, port_bond_direction, port_status, ...
	    typefile, infofile);
	
	% Create a single status from the status vector s
	if max(abs(s)) == 0 % Causal
	  status(i) = 0;
	else
	  if max(s) == 1 % At least one component is overcausal

  end;
end;

% $$$ file_name = [full_name, '_', system_type]
file_name = [full_name, '_cbg.m'];
disp(['Writing ', file_name]);
cbgfilenum = fopen(file_name,'w');
write_cbg(cbgfilenum,full_name,system_type,bonds,status,components);
fclose(cbgfilenum);

% Return the port bonds - arrow orientated causality - and the direction 
if ~at_top_level % Not at top level
  j = abs(components(1:n_ports,1)) %relevant bond numbers
  port_bonds = bonds(j,:)
end;

disp('====================================');
disp(['END: ', full_name, ' (', fun_name, ')']);
disp('====================================');