ADDED   mttroot/mtt/lib/comp/simple/AF_eqn.m
Index: mttroot/mtt/lib/comp/simple/AF_eqn.m
==================================================================
--- /dev/null
+++ mttroot/mtt/lib/comp/simple/AF_eqn.m
@@ -0,0 +1,60 @@
+function  structure = AF_eqn(name,bond_number,bonds,direction,cr,args, ...
+    structure,eqnfile);
+% AF_eqn - equations for flow amplifier
+% 
+%     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
+%     %%%%% Model Transformation Tools %%%%%
+%     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% 
+% Matlab function  AF_eqn
+% structure = AF_eqn(bond_number,bonds,direction,cr,args, ...
+%    structure,eqnfile);
+
+% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% %% Version control history
+% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% %% $Id$
+% %% $Log$
+% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+
+% Copyright (c) P.J. Gawthrop, 1996.
+
+if nargin<6
+  eqnfile = 'stdout';
+end;
+
+% Check that there are exactly two bonds.
+if check_bonds(bonds,2,'AF')==0
+  return
+end
+
+% There are 2 ports; extract the information
+e_1 = bonds(1,1);
+f_1 = bonds(1,2);
+e_2 = bonds(2,1);
+f_2 = bonds(2,2);
+
+% Effort on port 1 is always zero
+   fprintf(eqnfile, '%s := 0;\n', ...
+      varname(name,bond_number(1), 1));
+  
+LHS_cause = -1;
+RHS_cause = -1;
+
+if f_2 == 1 				% Unicausal: f_2 := f_1
+  LHS_number = bond_number(2);
+  RHS_number = bond_number(1);
+else 	                                % Bicausal: f_1 := f_2      
+  LHS_number = bond_number(1);
+  RHS_number = bond_number(2);
+end
+
+oneeqn(name,LHS_number,LHS_cause,RHS_number,RHS_cause,cr,args,eqnfile);
+
+
+
+
+
+
+