function structure = cbg2ese(system_name, system_type, full_name, infofile)
% 
%     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
%     %%%%% Model Transformation Tools %%%%%
%     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% 
% Matlab function  cbg2ese.m
% Acausal bond graph to causal bond graph: mfile format

% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %% Version control history
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %% $Id$
% %% $Log$
% %% Revision 1.3  1996/08/18 20:08:02  peter
% %% Included additional structure: structure(5) = zero_outputs.
% %%
% %% 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
% %%
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


pc = '%';
if nargin<3
  eqnfile = 'stdout';
end;
if nargin<4
  infofile = 'stdout';
end;

% Create the (full) system name
if length(full_name)==0
  full_name = system_name;
  system_type = system_name;
else
  full_name = [full_name, '_', system_name];
end;

full_name_type = [full_name, '_', system_type];
ese_name = [system_name, '_ese.r'];
cbg_name = [full_name_type, '_cbg'];
abg_name = [system_type, '_abg'];
cmp_name = [system_type, '_cmp'];
% Return if cbg file doesn't exist
if exist(cbg_name)~=2
  return
end;

% Setup file
filenum = fopen(ese_name, 'w');

% Evaluate the system function to get the bonds
  eval(['[junk,components]=', abg_name, ';']);
  eval(['bonds=', cbg_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);
  
  %Structure matrix [states,nonstates,inputs,outputs,zero_outputs]
  structure = zeros(1,5);


  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;
    eval([ '[comp_type,comp_name,cr,args,repetitions] = ', cmp_name, '(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;

    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']);
	repetitions = 1;
      end;
    end;
    
    if repetitions>1
      odd_bonds = bond_list(1:2:ports-1);
      even_bonds = bond_list(2:2:ports);
      next_bond = max(max(abs(components)))+1;
    end;
    
    for k = 1:repetitions
      if repetitions>1
	if k==1
	  bond_list(1:2:ports-1) = odd_bonds;
	else
	  bond_list(1:2:ports-1) = bond_list(2:2:ports);
	end;
	
	if k==repetitions
	  bond_list(2:2:ports) = even_bonds;
	else
	  new_bonds = [next_bond:next_bond+port_pairs-1];
	  next_bond = next_bond+port_pairs;
	  bond_list(2:2:ports) = new_bonds;
	end;
      end;
	
      % Invoke the appropriate equation-generating procedure
      eqn_name = [comp_type, '_eqn']
      if exist(eqn_name)~=2 % Try a compound component
	cbg2ese(comp_name, comp_type, full_name, infofile);
      else % its a simple component
	eval(['structure = ', ...
	      eqn_name, ...
	      '(bond_list,comp_bonds,direction,cr,args,structure,filenum);' ]);
      end;
    end;
  end;

fclose(filenum);