Index: mttroot/mtt/bin/trans/m/rbg2ibg.m
==================================================================
--- mttroot/mtt/bin/trans/m/rbg2ibg.m
+++ mttroot/mtt/bin/trans/m/rbg2ibg.m
@@ -73,12 +73,12 @@
     endif
     
     ## The (signed) bond corresponding to the ith port label
     port_bond(i) = near_bond(1) * sign(1.5 - near_bond(2));
   endfor
-  
   port_bond
+
   ## Now have (signed) bond (port_bond(i)) corresponding to the ith port
   ## Create inverse mapping
   for i = 1:n_bonds
     eval(sprintf('bond_port_head%i = "[]"', i))
     eval(sprintf('bond_port_tail%i = "[]"', i))
@@ -97,13 +97,12 @@
   ## col 1 of comp_near_bond contains component nearest to the arrow end
   ## col 2 of comp_near_bond contains component nearest other end
   for i = 1:n_bonds
     comp_near_bond(i,:) = adjcomp(arrow_end(i,:), other_end(i,:), \
 				  rcomponents);
-    [hc_type, hc_name] = eval([name, '_cmp(comp_near_bond(i,1))']);
-    [tc_type, tc_name] = eval([name, '_cmp(comp_near_bond(i,2))']);
   endfor
+  comp_near_bond
 
   ## Deduce causality from the strokes (if any)
   causality = zeros(n_bonds,2);
   if (n_strokes > 0)
     ## Find location of centre and ends of stroke
@@ -144,19 +143,41 @@
 	flow_side = stroke_direction * arrow_vector(j,:)' > 0;
 	causality(j,1+flow_side) = 2 * which_end - 1;
       endif
     endfor
   endif
+  causality
 
-  ## Return data
+  ## Write data
   for i = 1:n_bonds
+    [hc_type, hc_name] = eval([name, '_cmp(comp_near_bond(i,1))']);
+    [tc_type, tc_name] = eval([name, '_cmp(comp_near_bond(i,2))']);
+    ## components
     eval(sprintf("bonds.bond%i.head.component\t= '%s:%s'", i, hc_type, \
 		 hc_name));
     eval(sprintf("bonds.bond%i.tail.component\t= '%s:%s'", i, tc_type, \
 		 tc_name));
+    ## ports
     eval(sprintf("bonds.bond%i.head.ports\t= bond_port_head%i", i, i));
     eval(sprintf("bonds.bond%i.tail.ports\t= bond_port_tail%i", i, i));
+    ## causality
+    if (causality(i,1) == 1)
+      effort_causality = "head"
+    elseif (causality(i,1) == -1)
+      effort_causality = "tail"
+    else
+      effort_causality = "none"
+    endif
+
+    if (causality(i,2) == 1)
+      flow_causality = "tail"
+    elseif (causality(i,2) == -1)
+      flow_causality = "head"
+    else
+      flow_causality = "none"
+    endif
+    
+    eval(sprintf("bonds.bond%i.causality.effort\t= '%s'", i, effort_causality));
+    eval(sprintf("bonds.bond%i.causality.flow\t= '%s'", i, flow_causality));
   endfor
-  
-  
-  
+
 endfunction

Index: mttroot/mtt/bin/trans/m/write_ibg.m
==================================================================
--- mttroot/mtt/bin/trans/m/write_ibg.m
+++ mttroot/mtt/bin/trans/m/write_ibg.m
@@ -11,14 +11,17 @@
   format_ce = "  %s.bonds.b%i.causality.effort\t= \"%s\";\n";
   format_cf = "  %s.bonds.b%i.causality.flow\t= \"%s\";\n";
 
   fprintf(fid, "## -*-octave-*-\n\n");
   fprintf(fid, "function [%s] = %s_ibg\n\n", system_name, system_name);
-  fprintf(fid, "## Intermediate bond graph representation of %s\n", \
+  fprintf(fid, "  ## Intermediate bond graph representation of %s\n", \
 	  system_name);
 
-  fprintf(fid, "## Generated by MTT on %s\n", ctime(time));
+  fprintf(fid, "  ## Generated by MTT on %s\n", ctime(time));
+  fprintf(fid, "  ## head refers to the harpoon end of a bond\n");
+  fprintf(fid, "  ## tail refers to the other end of a bond\n");
+  fprintf(fid, "  ## causality.? is the end at which ? is imposed\n\n");
 
   for i=1:nbonds
     fprintf(fid, "\n  ## bond %i\n", i);
     fprintf(fid, format_hc, system_name, i, \
 	    eval(sprintf("bonds.bond%i.head.component", i)));
@@ -26,13 +29,15 @@
 	    eval(sprintf("bonds.bond%i.tail.component", i)));
     fprintf(fid, format_hp, system_name, i, \
 	    eval(sprintf("bonds.bond%i.head.ports", i)));
     fprintf(fid, format_tp, system_name, i, \
 	    eval(sprintf("bonds.bond%i.tail.ports", i)));
-    fprintf(fid, format_ce, system_name, i, "FIXME");
-    fprintf(fid, format_cf, system_name, i, "FIXME");
+    fprintf(fid, format_ce, system_name, i, \
+	    eval(sprintf("bonds.bond%i.causality.effort", i)));
+    fprintf(fid, format_cf, system_name, i, \
+	    eval(sprintf("bonds.bond%i.causality.flow", i)));
   endfor;
 
   fprintf(fid, "\nendfunction\n");
   fclose(fid);
 
 endfunction;