# [bonds,status] = abg2cbg(system_name, system_type, full_name, port_bonds, infofile)

# ###############################################################
# ## Version control history
# ###############################################################
# ## $Id$
# ## $Log$



# ## Revision 1.35  1998/08/24 10:16:32  peterg
# ## Coverted to new structure - still needs status sorting.
# ##
# ## Revision 1.34  1998/08/24 07:35:03  peterg
# ## About to go to new abg format.
# ##
# ## Revision 1.33  1998/07/29 13:36:37  peterg

  else
    [n_subsystems,junk] = size(struct_elements(ABG.subsystems));
  endif
  
  if struct_contains(ABG,"ports")# Are there any ports?
    [n_ports,junk] = size(struct_elements(ABG.ports));
    port_bond_index=zeros(n_ports,1);
    for port = ABG.ports		# Find indices of the internal port bonds

       port_bond_index(port.index) = port.connections;
    endfor
    port_bond_index=abs(port_bond_index);
  else
    n_ports = 0;
  endif				   

# bonds,port_bonds

# Causality indicator
  total = 2*n_bonds;
  done = sum(sum(abs(ABG.bonds)))/total*100;


field=["ports";"subsystems"];	# Do for both ports and subsystems -
#				# ports first
  for i=1:2

    if struct_contains(ABG,field(i,:));
      eval(["ABG_field = ABG.",field(i,:), ";"]);
      
# Outer while loop sets preferred causality
      ci_index=1;

      for [subsystem,name] = ABG_field# Set new status field to -1
    	eval(["ABG_field.",name,".status=-1;"]);
      endfor;
      
      while( ci_index>0)
    	old_done = inf;
	
    	while done!=old_done	# Inner loop propagates causality
	  old_done = done;
	  for [subsystem,name] = ABG_field
      	    if subsystem.status != 0 # only do this if causality not yet complete
	      
				# Get the bonds on this component
	      comp = subsystem.connections;
	      bond_list = abs(comp);
	      direction = sign(comp)'*[1 1];
              n_bonds = length(bond_list);
	      
				# Get the component details
				#eval([ "[comp_type,name,cr,arg] = ", system_type, "_cmp(i);" ]);
	      
				# Change name of 0 and 1 components -- matlab doesn't like numbers here
	      if strcmp(subsystem.type,"0")
	    	subsystem.type = "zero";
	      end;
	      if strcmp(subsystem.type,"1")
	    	subsystem.type = "one";
	      end;
	      
				# Component causality procedure name
	      cause_name = [subsystem.type, "_cause"];
	      
				#Component equation procedure name
	      eqn_name = [subsystem.type, "_eqn"];
	      
				# Bonds on this component (arrow-orientated) -- these become the
				# port bonds on the ith component of this subsystem.
	      
	      comp_bonds=[];
	      for kk = 1:n_bonds
	    	comp_bonds(kk,:) = ABG.bonds(bond_list(kk),:);
	      end;
	      
	      
				# Invoke  the appropriate causality procedure
	      if exist(eqn_name)!=2 # Try a compound component
				# Port status depends on whether the corresponding bonds are
				#  fully causal at this stage.
            	one = ones(n_bonds,1);
            	port_status = (sum(abs(comp_bonds'))'==2*one) - one;
		
				# Direction of bonds on the ports (0 if next to port)
				#port_bond_direction = -sign(components(i,1:n_bonds))';
	    	port_bond_direction = -sign(subsystem.connections)';
				# If there is a predefined causality function; use it
            	if exist(cause_name)==2
    				# Convert from arrow orientated to component orientated causality
		  comp_bonds = comp_bonds.*(port_bond_direction*[1 1]);
		  
				# Evaluate the built-in causality procedure
		  eval([ "[comp_bonds] = ", cause_name, "(comp_bonds);" ]);
		  
				# and convert from component orientated to arrow orientated causality
		  comp_bonds = comp_bonds.*(port_bond_direction*[1 1]); 
            	end;
		
	    	[comp_bonds,subsystem.status] = abg2cbg(name, subsystem.type, full_name, 
							comp_bonds, port_bond_direction, port_status, ...
						    	typefile, infofile, errorfile);
				#	# Create a single status from the status vector s
				#	    if max(abs(s)) == 0 # Causal

  if at_top_level
    mtt_info(sprintf("Final causality of %s is %3.0f%s complete.", ...
		     full_name, done, pc), infofile);
    
    if done<100
      mtt_error(sprintf("Unable to complete causality"),errorfile);
    end;
    
    
				# List overcausal bonds
				#  [over_causal_bonds,n] = getindex(status,1);
				#  if n>0
				#    for i=over_causal_bonds'
				#      eval([ "[comp_type,name] = ", system_type, "_cmp(i);" ]);
				#      mtt_info(sprintf("Component #s (#s) is overcausal", name, subsystem.type), ...
				#	  infofile);
				#    end;
				#  end;
    
				# List undercausal bonds
				#  [under_causal_bonds,n] = getindex(status,-1);
				#  if n>0
				#    for i=under_causal_bonds'
				#      eval([ "[comp_type,name] = ", system_type, "_cmp(i);" ]);
				#      mtt_info(sprintf("Component #s (#s) is undercausal", name, subsystem.type), ...
				#	  infofile);
				#    end;
				#  end;
    
				#  List over and undercausal bonds and set status
    
  endif
  

  disp(["Writing ", full_name]);
  write_cbg(full_name,system_type,ABG);
  
				# Return the port bonds - arrow orientated causality - and the direction 
  status=0;