function structure = cbg2ese(system_name, system_type, system_cr, ...
    system_args, full_name, full_name_repetition, ...
    repetition,...
    structure, structure_file, infofile)
% 
%     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
%     %%%%% Model Transformation Tools %%%%%
%     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% 
% Matlab function  cbg2ese.m
% Acausal bond graph to causal bond graph: mfile format
% Structure matrix [states,nonstates,inputs,outputs,zero_outputs]

% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %% Version control history
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %% $Id$
% %% $Log$
% %% Revision 1.11  1996/12/07 18:20:11  peterg
% %% Replaces null argument by a default and tells user.
% %%
% %% Revision 1.10  1996/12/07 17:37:07  peterg
% %% Now handles numbered SS ports appearing at top level.
% %%
% %% Revision 1.9  1996/12/04 21:49:47  peterg
% %% Compares full-name with empty string (instead of testing for zero
% %% length)
% %%

% %% Initial revision
% %%
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

system_name, system_type, full_name,

pc = '%';

% Set up the names corresponding to the structure matrix.
structure_name = [
  'state       ',
  'nonstate    ',
  'input       ',
  'output      ',
  'zero_output '];

	
% Are we at the top level of the heirarchy?
at_top_level = strcmp(full_name, '');

% Create the (full) system name
if at_top_level
  full_name = system_name;
  full_name_repetition = system_name;
  system_type = system_name;
else
  full_name = [full_name, '_', system_name];
  full_name_repetition = [full_name_repetition, ...
	'_', system_name, '_', num2str(repetition)];
end;


% $$$ full_name_type = [full_name, '_', system_type];
% $$$ cbg_name = [full_name_type, '_cbg'];
cbg_name = [full_name, '_cbg'];
% Return if cbg file doesn't exist
if exist(cbg_name)~=2
  disp([cbg_name, ' does not exist']);
  return
end;

% Setup files
ese_name = [full_name_repetition, '_ese.r'];
ese_file = fopen(ese_name, 'w');

fprintf(ese_file, '\n%s%s Equation file for system %s (file %s)\n', ...
    pc, pc, full_name_repetition, ese_name);
fprintf(ese_file, '%s%s Generated by MTT\n\n', pc, pc);

% Evaluate the system function to get the bonds
  eval(['[bonds,status,system_type] = ', cbg_name, ';']);
  abg_name = [system_type, '_abg'];
  cmp_name = [system_type, '_cmp'];
  eval(['[junk,components]=', abg_name, ';']);

      name_r = full_name_repetition;
      eqn_name = [comp_type, '_eqn']
      
      if exist(eqn_name)~=2 % Try a compound component
	disp('---PUSH---');
	structure = cbg2ese(comp_name, comp_type, cr, args, ...
	    full_name, full_name_repetition, ...
	    k, structure,  structure_file, infofile);
	
	% Link up the bonds
	fprintf(ese_file, ...
	    '\n\t%s Equations linking up subsystem %s (%s)\n\n', ...
	    pc, comp_name, comp_type);
	name_comp_name = sprintf('%s_%s_%d', ...
	    full_name_repetition, comp_name, k);
	
	for port_number=1:length(bond_list)
	  % Effort
	  if comp_bonds(port_number,1)==1 % Source
	     fprintf(ese_file, '%s_MTTu%d := %s;\n', ...
		 name_comp_name, port_number, varname(name_r, ...
		 bond_list(port_number),1));
	   else % sensor
	     	 fprintf(ese_file, '%s := %s_MTTy%d;\n', ...
		 varname(name_r, ...
		 bond_list(port_number),1), name_comp_name, port_number);
	  end;
	  % flow
	  if comp_bonds(port_number,2)==-1 % Source
	     fprintf(ese_file, '%s_MTTu%d := %s;\n', ...
		 name_comp_name, port_number, varname(name_r, ...
		 bond_list(port_number),-1));
	   else % sensor
	     	 fprintf(ese_file, '%s := %s_MTTy%d;\n', ...
		 varname(name_r, ...
		 bond_list(port_number),-1), name_comp_name, port_number);
	   end;	
	 end;
	
	disp('---POP---');
      else % its a simple component
	fprintf(ese_file, '\n\t%s Equations for component %s (%s), repetition %d\n\n', ...
	    pc, comp_name, comp_type,k);
	
	% Take port SS to be ordinary SS at top level
	if at_top_level & strcmp(comp_type, 'SS') 
	  effort_attribute = cr;
	  flow_attribute = args;
	  if strcmp(effort_attribute, 'MTT_port') % Its a numbered port
	    effort_attribute = 'external';
	    flow_attribute = 'external';
	    cr = effort_attribute;
	    args = flow_attribute;
	  end;
	end;

	% Save the current structure
	old_structure = structure;
	
	% Generate the simple component equations
	eval(['structure = ', ...
	      eqn_name, ...
	      '(name_r,bond_list,comp_bonds, ...
	      direction,cr,args,structure,ese_file);' ]);
      
	% If structure has changed, write info to structure file.
	structure_change = structure-old_structure;
	structure_changes = sum(structure_change);
	
	if structure_changes>0
	  which_indices = getindex(structure_change,1);
	  which_indices = which_indices(:,2)';
	  for which_index=which_indices
	    value = structure(which_index);
	    fprintf(structure_file, ...
		'%s\t%1.0f\t%s\t%s\t%1.0f\n', ...
		structure_name(which_index,:), value, ...
		comp_name, full_name, repetition);
	    end;
	  end;
	
      end;
    end;
  end;

  % Close the files
  fclose(ese_file);