function structure = cbg2ese(system_name, system_type, system_cr, ...
    system_args, full_name, full_name_repetition, ...
    repetition,...
    structure, structure_file,infofilenum)
% Set up globals to count the component inputs and outputs. This relies on
% the named SS (the ports) being in the correct order. Using globals here
% avoids changing the common argument list for all _eqn files for something
% which is only used for named SS components.
  global local_u_index
  global local_y_index
  global at_top_level
% 
%     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
%     %%%%% 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 1.24  1998/07/27 10:26:02  peterg
% %% No change - but fixed bug in alias_args
% %%
% %% Revision 1.23  1998/07/08 12:33:51  peterg
% %% Reinstated the infofilenum parameter.
% %%
% %% Revision 1.22  1998/07/04 07:10:27  peterg
% %% Don't evaluate alias if no constitutive relationship or args and write
% %% message.
% %%

% %%
% %% Revision 1.2  1996/08/08 18:08:11  peter
% %% Sorted out file naming sceme
% %%
% %% Revision 1.1  1996/08/08 15:53:23  peter
% %% 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  ",
  "unknown_input"];

	
% 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,components] = ", cbg_name, ";"]);
  abg_name = [system_type, "_abg"];
  cmp_name = [system_type, "_cmp"];
  alias_name = [system_type, "_alias"];

% No longer needed - cbg now has components:  
%  eval(["[junk,components]=", abg_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);
  n_components = n_components
  
  % Set up the first dummy bond number - needed for repetative components

  for i = 1:n_components
    comp = nozeros(components(i,:));
    bond_list = abs(comp);
    direction = sign(comp)'*[1 1];
    % Convert from arrow orientated to component orientated causality
    comp_bonds = bonds(bond_list,:).*direction;

disp("---- Component ---");    
    % Get the component details
    eval([ "[comp_type,comp_name,cr,args,repetitions] = ", cmp_name, "(i)" ...
	  ]);
						   
    % Alias the args list -- if not at top level
    message = sprintf("\tfor component  %s (%s) within %s",\
                      comp_name,comp_type,full_name);    
    if (length(system_args)>0)
      args = alias_args(args,alias,";",message,infofilenum)
    end;
    if (length(system_cr)>0)
      cr = alias_args(cr,alias,";",message,infofilenum)
    end;

    % Substitute positional ($1 etc) arguments
    cr = subs_arg(cr,system_cr, ...
	"lin",full_name,comp_type,comp_name,infofilenum);
    args = subs_arg(args,system_args, ...
	"1",full_name,comp_type,comp_name,infofilenum);
    
    % 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;
    
    ports = length(bond_list);
    
    if repetitions>1
      port_pairs = ports/2;
      if round(port_pairs)~=port_pairs;
	mtt_info(["Repeated component ", comp_name, ...
	      " has an odd number of ports - ignoring repetitions"], infofilenum);
	repetitions = 1;
      end;
    end;
    
    if repetitions>1
      odd_bonds = bond_list(1:2:ports-1);
      even_bonds = bond_list(2:2:ports);

	  bond_list(2:2:ports) = new_bonds;
	end;
	
      end;
	
      % Invoke the appropriate equation-generating procedure
      name_r = full_name_repetition;
      eqn_name = [comp_type, "_eqn"]
      
      if exist(eqn_name)~=2 % Try a compound component
	disp("---PUSH---"); bond_list, comp_name, comp_type
	structure = cbg2ese(comp_name, comp_type, cr, args, ...
	    full_name, full_name_repetition, ...
	    k, structure,  structure_file, infofilenum);
	
	% 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);

printf("\n\t%s Equations linking up subsystem %s (%s)\n\n",\
	    pc, comp_name, comp_type);
bond_list

	u_index = 0; y_index = 0; % Count the inputs and outputs
	for port_number=1:length(bond_list)
	  % Effort
	  if comp_bonds(port_number,1)==1 % Source
	     u_index = u_index + 1;
	     fprintf(ese_file, "%s_MTTu%d := %s;\n", ...
		 name_comp_name, u_index, varname(name_r, ...
		 bond_list(port_number),1));
	   else % Sensor
	     y_index = y_index + 1;
	     fprintf(ese_file, "%s := %s_MTTy%d;\n", ...
		 varname(name_r, ...
		 bond_list(port_number),1), name_comp_name, y_index);
	  end;
	  % Flow
	  if comp_bonds(port_number,2)==-1 % Source
	     u_index = u_index + 1;
	     fprintf(ese_file, "%s_MTTu%d := %s;\n", ...
		 name_comp_name, u_index, varname(name_r, ...
		 bond_list(port_number),-1));
	   else % Sensor
	     y_index = y_index + 1;
	     fprintf(ese_file, "%s := %s_MTTy%d;\n", ...
		 varname(name_r, ...
		 bond_list(port_number),-1), name_comp_name, y_index);
	   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);
	
	 
	% Is it a named port? (Name begins with [)
        Named_Port = (comp_name(1)=="[");

       if Named_Port %Add [ to start of name
	 name_r = ["[" name_r];
       end;

#	% 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;
	
	% The following line is to avoid probs with multiport C or I
	% it needs changing to handle multi ports correctly
	structure_changes = sum(structure_change);
	
	structure_change = structure_change>zeros(size(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);
	    value_change=value-old_structure(which_index);
	    for k=1:value_change
	      fprintf(structure_file, ...
		  "%s\t%1.0f\t%s\t%s\t%1.0f\n", ...
		  structure_name(which_index,:), value-k+1, ...
		  comp_name, full_name, repetition);
	      end;
 	    end;
 	  end;
	
      end;