ibg	= ${sys}_ibg;
cbg	= ${name}_cbg;

## get connections data: ${sys}_connections
## structure with two cell arrays: head and tail 
## the index of each array element is the bond index
## the value of each array element is a component name
load -ascii ${sys}_connections.dat;
load -text ${sys}_connections.dat;
con	= ${sys}_connections;

nibgbonds = length (fieldnames (ibg.bonds));
ncbgbonds = length (con.head);

## map cbg data to connection data
for [bond, bond_name] = ibg.bonds