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

% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %% Version control history
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %% $Id$
% %% $Log$
% %% Revision 1.3  1996/08/09 08:26:35  peter
% %% Cosmetic tidy up.
% %%
% %% Revision 1.2  1996/08/04 18:37:57  peter
% %% Fixed  no causal strokes bug.
% %%
% %% Revision 1.1  1996/08/04 18:30:14  peter
% %% Initial revision
% %%
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


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

% Xfig scaling factor
scale = 1200.0;

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

    arrow_end;
 
% Locate the bond end nearest to each port
for i = 1:n_ports
  near_bond = adjbond(rports(i,1:2),arrow_end,other_end);
  port_near_bond(i,:) = [near_bond, rports(i,3)];
end;
port_near_bond

% Locate the components at the ends of each bond
for i = 1:n_bonds
  comp_near_bond(i,:) = adjcomp(arrow_end(i,:),other_end(i,:),rcomponents);
end;
comp_near_bond

% Produce a list of bonds on each component - sorted if explicit port numbers
for i = 1:n_components
  [index,n] = getindex(comp_near_bond,i);

  if index(1,1) ~= 0 % Then its a genuine component 
    one = ones(n,1);
    bond_list = index(:,1);
    bond_list = index(:,1); % either end of bond at component
    
    % Default sort of bonds (ie no change)
    sort_index = [1:n]'; 
    
    if n_ports>0
      % Are the component ports numbered? (either they all are or none are)
      k=0;
      for j = 1:n
	[port_index,m] = getindex(port_near_bond(:,1),bond_list(j));
	[port_index,m] = getindex(port_near_bond(:,1:2),bond_list(j));
	if m==1 % exactly one number on this bond
	  if index(j,2)==port_near_bond(port_index,2) % same end
	    k=k+1;
	    port_number(k,1) = port_near_bond(port_index,3);
	  end;
	end;
      end;
      

      % Must have a lable for each port or non at all
      if k==n
	[junk,sort_index]=sort(port_number);
      elseif k~=0
	info = sprintf(... 
	    'Component at (%1.3f,%1.3f) has inconsistent port numbers', ...
	    rcomponents(i,1)/scale, rcomponents(i,2)/scale);
	mtt_info(info,infofile);
	mtt_info(info,fnum);
      end;
    end;
  end;

  % direction is 1 if arrow at component else -1
  direction = -sign(index(:,2)-1.5*one);
  signed_bond_list = bond_list.*direction;

      flow_side = stroke_direction*arrow_vector(j,:)'>0;
      causality(j,1+flow_side) = 2*which_end-1;
    end;
  end;
end;

bonds = causality;
fclose(fnum);