function [port_bonds, status] = abg2cbg(system_name, ...
    system_type, full_name, ...
    port_bonds, port_bond_direction, port_status, typefile, infofile)
    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 1.28  1998/07/08 09:23:42  peterg
% %% Undid the previous change -- needs more thought.
% %%
% %% Revision 1.27  1998/07/03 19:03:31  peterg
% %% Always override the causality of port bonds!
% %%
% %% Revision 1.26  1998/06/27 13:24:04  peterg
% %% Causality now set correctly for:
% %% 	multi-port C and I
% %% 	C and I with arrows pointing in

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

% If no such function - then there is nothing to be done.
if exist(fun_name)~=2
  mtt_info(['m-file ', fun_name, ' does not exist'], infofile);
  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]=', fun_name, ',']);
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
% 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)) % relevant bond numbers
  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));
      mtt_info(sprintf("Flip port %i",i),infofile);
      % 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);

% 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);
  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);

% 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; 
ci_index=1;

while( ci_index>0)
  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;
  
    for i = n_port_bonds+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,:))
	comp = nozeros(components(i,:));
	bond_list = abs(comp);
	direction = sign(comp)'*[1 1];
        n_bonds = length(bond_list);

	% Get the component details
	eval([ '[comp_type,name,cr,arg] = ', system_type, '_cmp(i);' ]);

         % and convert from component orientated to arrow orientated causality
         comp_bonds = comp_bonds.*(port_bond_direction*[1 1]); 
        end;

	[comp_bonds,s] = abg2cbg(name, comp_type, full_name, 
            comp_bonds, port_bond_direction, port_status, ...
	    typefile, infofile);
	    typefile, infofile, errorfile);
	
	% 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
	    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
	% 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
       % comp_bonds_out = comp_bonds;
      end;
      
      % Update the full bonds list
      bonds(bond_list,:) = comp_bonds
      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));
    
  end;
  
  % Set causality of a C or I which is not already set
  [ci_index,prefered] = getdynamic(status,system_type);
  if ci_index>0
    disp('Set causality of a C or I which is not already set')
    ci_bond_index = nozeros(components(ci_index,:)); # Get all bonds
    ci_direction = sign(ci_bond_index);
    ci_bond_index = abs(ci_bond_index);
    bonds(ci_bond_index,1:2) = prefered*ci_direction'*[1 1];
  end;
  
end;

% Print final causality
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
	  mtt_error(sprintf("Unable to complete causality"),errorfile);
  end;
 
  % List overcausal bonds
  [over_causal_bonds,n] = getindex(status,1);
  if n>0
    for i=over_causal_bonds'
      eval([ '[comp_type,name] = ', system_type, '_cmp(i);' ]);
      mtt_info(sprintf('Component %s (%s) is overcausal', name, comp_type), ...
	  infofile);

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,:)
  j = abs(components(1:n_ports,1)); %relevant bond numbers
  port_bonds = bonds(j,:);
end;

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