function [bonds,components] = rbg2abg(rbonds,rstrokes,rcomponents,rports,infofile)
function [bonds,components] = rbg2abg(name,rbonds,rstrokes,rcomponents,port_coord,port_name,infofile)

% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %% Version control history
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %% $Id$
% %% $Log$
% %% Revision 1.11  1997/04/29 09:12:37  peterg
% %% Added error message if port label near to >1 bond.
% %%
% %% Revision 1.10  1997/03/17  13:45:42  peterg
% %% Added more error info.
% %%
% %% Revision 1.9  1996/12/31  11:25:57  peterg
% %% Clearer error messages for incorrect ports.
% %%
% %% Revision 1.8  1996/12/04 21:52:39  peterg

if nargin<5
  infofile='stdout';
else
  fnum = fopen(infofile, 'w');
end;

%Default to no components
components = [0];

% Xfig scaling factor
scale = 1200.0/2.54546;

% Rotation matrix
rot = [0 -1; 1 0];

  error('Incorrect rbonds matrix: must have 6 columns');
end;

% Find number of components
[n_components,columns] = size(rcomponents);

% Find number of ports
[n_ports,columns] = size(rports);
[n_ports,columns] = size(port_coord);

% Determine coordinates of the arrow end of the bond and the other end
other_end_1 = rbonds(:,1:2);
arrow_end   = rbonds(:,3:4);
other_end_2 = rbonds(:,5:6);

distance_1   = length2d(other_end_1 - arrow_end);
distance_2   = length2d(other_end_2 - arrow_end);
which_end    = (distance_1>distance_2)*[1 1];
one          = ones(size(which_end));
other_end    = which_end.*other_end_1 + (one-which_end).*other_end_2;
arrow_vector = ( which_end.*other_end_2 + (one-which_end).*other_end_1 ) - ...
    arrow_end;
 
% Locate the bond end nearest to each port
% col 1 of port_near_bond contains a signed bond number (+ for arrow end)
% col 2  of port_near_bond contains the corresponding port number
for i = 1:n_ports
   [i rports(i,1:2)/scale rports(i,3)]
   near_bond = adjbond(rports(i,1:2),arrow_end,other_end)
   near_bond = adjbond(port_coord(i,1:2),arrow_end,other_end);
   [rows,cols]=size(near_bond);
   if rows>1
     error(sprintf ...
	 ("A port is near to more than one bond at coordinates %g,%g\n", ...
	 rports(i,1)/scale,  rports(i,2)/scale));
	 port_coord(i,1)/scale,  port_coord(i,2)/scale));
   end;
  %The (signed) bond corrsponding to the ith port label
  signed_bond = near_bond(1)*sign(1.5-near_bond(2));
  port_near_bond(i,:) = [signed_bond, rports(i,3)];
  signed_bonds(i) = signed_bond;
end;

% Locate the components at the ends of each bond
% col 1 of comp_near_bond contain the component nearest to the arrow end
% col 2 of comp_near_bond contain the component nearest to the other end
for i = 1:n_bonds
  comp_near_bond(i,:) = adjcomp(arrow_end(i,:),other_end(i,:),rcomponents);
end;

% Produce a list of bonds on each component - sorted if explicit port numbers
for i = 1:n_components    
  %Get component type
  eval(['[comp_type, comp_name] = ', name, '_cmp(i)']);
  

  if comp_type=='0'
    comp_type = 'zero';
  end

  if comp_type=='1'
    comp_type = 'one';
  end

  % and the port list (if its not an elementary component)
    if exist([comp_type, '_cause'])==0
      eval(['[junk1,junk2,junk3,junk4,junk5,port_list]=', comp_type, '_rbg;']);
    else
      port_list=comp_port(comp_type);
    end;

  port_list

  % There are n bonds on this component with corresponding index
  [index,n] = getindex(comp_near_bond,i);
  
  % Error message in case we need it!
  port_error = sprintf(... 
      'Component at (%1.3f,%1.3f) has inconsistent port numbers', ...
      rcomponents(i,1)/scale, rcomponents(i,2)/scale);

  if index(1,1) ~= 0 % Then its a genuine component 
    
    % Create the signed list of bonds on this component
    one = ones(n,1);
    bond_list = index(:,1); %  bond at component
    bond_end = index(:,2);  % which end of bond at component?
    direction = -sign(bond_end-1.5*one);
    signed_bond_list = bond_list.*direction;

    % Default sort of bonds (ie no change)
    sort_index = [1:n]'; 
    
    [n_ports,junk] = size(port_list);
    unsorted_port_list="";
    if n_ports>0 % then there are some numbered ports 
      % so find those associated with the bonds on this component.
      k=0; port_number=[];
      k=0; 
      for j = 1:n
	b = signed_bond_list(j); 
	% Find the port label on component end of bond (if any)
	[port_index,m] = getindex(port_near_bond(:,1),b);
	[port_index,m] = getindex(signed_bonds,b);
	if m==1
	  k=k+1;
	  port_number(k,1) = port_near_bond(port_index,2);
	  unsorted_port_list(k,:) = port_name(port_index,:);
	  end;
      end;

      [n_unsorted_ports,m_unsorted_ports] = size(unsorted_port_list);
      % Must have a lable for each port or non at all
      if k==n % Then a full set of port numbers
	[sorted,sort_index]=sort(port_number);
	
      if m_unsorted_ports<2
        n_unsorted_ports = 0;
      end;

	%Check that all the numbers (1..n) are there
	if sum(sorted==[1:n]')~=n % There is something wrong
	  mtt_info(port_error,fnum);
      unsorted_port_list
	  mtt_info(sprintf('\t it must have consecutive ports labels from 1:%1.0f\n', n), ...
	      fnum);
	  port_str = sprintf('\t the port labels are: ');
	  for kk=1:k
	    port_str=sprintf('%s %1.0f', port_str, port_number(kk));
	  end;

      % One port defaults:
      if n_ports==1
        if n_unsorted_ports==0
          unsorted_port_list(1,:) = port_list(1,:);
        end; 
	  mtt_info(port_str, fnum);
	end;
      else
	if k~=0
	  mtt_info(port_error,fnum);
      end;
      
      %Write out the signed bond list in the correct order
        for j = 1:n_ports
          name_k = unsorted_port_list(j,:);
          k = name_in_list(name_k, port_list)
          if k==0
            mtt_info(['Component ', comp_name, ' has an unrecognised port: ', name_k], infofile); 
	  mtt_info(sprintf('\t it must have 0 or %1.0f ports\n', n), fnum);
	  port_str = sprintf('\t the port labels are: ');
          else
	  for kk=1:k
	    port_str=sprintf('%s %1.0f', port_str, port_number(kk));
	  end;
          components(i,j) = signed_bond_list(k);     
          end;
	  mtt_info(port_str, fnum);
	end;
      end;
        end;
    end;
      
    end;
  end;
    
  end;
end;

  % Write out bond list sorted by port number (if any)
  for j = 1:length(sort_index)
    jj = sort_index(j);
    components(i,j) = signed_bond_list(jj);
  end;
end;

% Deduce causality from the strokes (if any).
causality = zeros(n_bonds,2);
if n_strokes>0
  % Find out location of centre and ends of stroke.
  stroke_end_1 = [rstrokes(:,1) rstrokes(:,2)];
  stroke_end_2 = [rstrokes(:,3) rstrokes(:,4)];

      causality(j,1+flow_side) = 2*which_end-1;
    end;
  end;
end;

bonds = causality;
fclose(fnum);