function [port_bonds, status] = abg2cbg(system_name, ...
    system_type, full_name, ...
    port_bonds, 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 1.16  1997/08/04 13:11:19  peterg
% %% Only change to component-orientated causality for simple components
% %% NOT for compound components.
% %%
% %% Revision 1.15  1997/01/05 12:25:59  peterg
% %% More informative message about port bonds incompatible with  ports
% %%
% %% Revision 1.14  1996/12/31 16:20:42  peterg
% %% Just write causality information at top level -- it gets a bit
% %% voluminous if written at deeper levels.
% %%

% %% Now recursively does causality on subsystems.
% %%
% %% Revision 1.1  1996/08/04 17:55:55  peter
% %% Initial revision
% %%
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

mtt_info(system_name, infofile);
pc = '%';
if nargin<1
  system_name = 'no_name';
end;

if nargin<4
  port_bonds = [];

% onto components
if at_top_level % Then at top level
  fprintf(typefile, '# Commands to map types onto subsystems\n');
  fprintf(typefile, '# File %s_type.sh\n', system_name);
  fprintf(typefile, '# Generated by MTT on %s\n\n', date);
end;




% Create the (full) system name
if at_top_level
  full_name = system_name;
  system_type = system_name;
else
  full_name = [full_name, '_', system_name];
end;


% Add to file to contain shell commands which map subsystem types 
% onto components
fprintf(typefile, '$1%s$2%s$3\n', system_type, full_name);

fun_name = [system_type, '_abg'];

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);
  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;

% 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

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


    bonds(j,:) = port_bonds;
    status(1:n_ports) = port_status;
  end
end;




% Causality indicator


total = 2*n_bonds;

done = sum(sum(abs(bonds)))/total*100;

% Outer while loop sets preferred causality
ci_index=1; 

while( ci_index>0)
  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 = 1:n_components
      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);

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

	% Change name of 0 and 1 components -- matlab doesn't like numbers here
	if strcmp(comp_type,'0')
	  comp_type = 'zero';
	end;
	if strcmp(comp_type,'1')
	  comp_type = 'one';
	end;
      
	% Component causality procedure name
	cause_name = [comp_type, '_cause'];
	
        % Bonds on this component (arrow-orientated)
      	port_bonds = bonds(bond_list,:);

      % 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(port_bonds'))'==2*one) - one;
	[port_bonds,s] = abg2cbg(name, comp_type, full_name, 
            port_bonds, 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
	    status(i) = 1;
	  else           % no component is overcausal but some are undercausal
	    status(i) = -1;
	  end;
	end;

      else % its a simple component
	port_bonds_in = port_bonds

	% Convert from arrow orientated to component orientated causality
	port_bonds = port_bonds.*direction;
	
	disp(['---', name, ' (', cause_name, ') ---']);

        % Evaluate the built-in causality procedure
	eval([ '[port_bonds,status(i)] = ', cause_name, '(port_bonds);' ]);

       % and convert from component orientated to arrow orientated causality
       port_bonds = port_bonds.*direction; 
       
       port_bonds_out = port_bonds

      end;
      
      % Update the full bonds list
      bonds(bond_list,:) = port_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
    bond_index = components(ci_index,1) % its a one port

      mtt_info(sprintf('Component %s (%s) is undercausal', name, comp_type), ...
	  infofile);
    end;
  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);
fclose(cbgfilenum);

% Return the port bonds - arrow orientated causality
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('====================================');