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

% 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 1.30  1998/07/27 20:29:49  peterg
% %% Had another go at causality ....
% %%   1. Impose external causality onto all port bonds
% %%   2. Set C_cause.m so that it DOESN'T set causality
% %%       -- I_cause is already ok !
% %%
% %% Revision 1.29  1998/07/10 09:01:42  peterg
% %% Added error + info file in new form
% %%
% %% Revision 1.28  1998/07/08 09:23:42  peterg
% %% Undid the previous change -- needs more thought.
% %%
% %% Revision 1.27  1998/07/03 19:03:31  peterg

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

% Evaluate the system function to get the bonds and number of ports
eval(['[bonds,components,n_ports,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,m_components] = 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 -- but not at top level
if (n_ports>0)&&(~at_top_level)
  port_bond_index = abs(components(1:n_ports,1:m_components))# relevant
							     # bond
							     # numbers
  port_bond_index = nozeros(reshape(\
                          port_bond_index',n_ports*m_components,1))'# vectorise

  for i=1:n_ports
    % Is the direction different?
    if (sign(components(i,1))~=port_bond_direction(i))
      mtt_info(sprintf("Flip port %i",i),infofile);
      % Flip direction at port
      components(i,1) = - components(i,1);
      % and at the other end

% 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_error(sprintf('%s: %1.0f port bonds incompatible with %1.0f ports', ...
               full_name, n_port_bonds, n_ports), errorfile);

  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

  ci_index
  old_done = inf;
  % Inner loop propagates causality
  while done~=old_done
   % disp(sprintf('Causality is %3.0f%s complete.', done, pc));
    old_done = done;
done,ci_index  
    for i = n_ports+1:n_components % Miss out the ports 
      if status(i) ~= 0 % only do this if causality not yet complete

	% Get the bonds on this component
	comp = nozeros(components(i,:));
	bond_list = abs(comp);
	direction = sign(comp)'*[1 1];
        n_bonds = length(bond_list);

	    status(i) = 1;
	  else           % no component is overcausal but some are undercausal
	    status(i) = -1;
	  end;
	end;

      else % its a simple component -- or explicit causality defined
	disp(['---', name, ' (', cause_name, ') ---']);
	comp_bonds_in = comp_bonds

	% Convert from arrow orientated to component orientated causality
	comp_bonds = comp_bonds.*direction;
	
        % Evaluate the built-in causality procedure
	eval([ '[comp_bonds,status(i)] = ', cause_name, '(comp_bonds);' ]);

        % and convert from component orientated to arrow orientated causality
        comp_bonds = comp_bonds.*direction; 
       
       comp_bonds_out = comp_bonds
      end;

      bonds,bond_list,comp_bonds
      % Update the full bonds list
      bonds(bond_list,:) = comp_bonds;
    end;
    end;
    
    done = sum(sum(abs(bonds)))/total*100;
    %disp(sprintf('Causality is %3.0f%s complete.', done, pc), infofile));

    ci_bond_index = abs(ci_bond_index);
    bonds(ci_bond_index,1:2) = prefered*ci_direction'*[1 1];
  end;
  
end;

% Print final causality
status
final_done =  (sum(status==zeros(n_components,1))/n_components)*100;

if at_top_level
  mtt_info(sprintf('Final causality of %s is %3.0f%s complete.', ...
      full_name, final_done, pc), infofile);

  if final_done<100

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

  port_bonds = bonds(port_bond_index,:) # Return port bonds
  status(1:n_ports) = zeros(1:n_ports); # Port status not relevant
end;

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